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1 | @node Using GNUnet | ||
2 | @chapter Using GNUnet | ||
3 | |||
4 | |||
5 | This tutorial is supposed to give a first introduction for users | ||
6 | trying to do something real with GNUnet. Installation and | ||
7 | configuration are specifically outside of the scope of this tutorial. | ||
8 | Instead, we start by briefly checking that the installation works, and | ||
9 | then dive into uncomplicated, concrete practical things that can be done | ||
10 | with the framework provided by GNUnet. | ||
11 | |||
12 | In short, this chapter of the ``GNUnet Reference Documentation'' will | ||
13 | show you how to use the various peer-to-peer applications of the | ||
14 | GNUnet system. | ||
15 | As GNUnet evolves, we will add new sections for the various | ||
16 | applications that are being created. | ||
17 | |||
18 | Comments on the content of this chapter, and extensions of it are | ||
19 | always welcome. | ||
20 | |||
21 | |||
22 | @menu | ||
23 | * Start and stop GNUnet:: | ||
24 | * First steps - Using the GNU Name System:: | ||
25 | * First steps - Using GNUnet Conversation:: | ||
26 | * First steps - Using the GNUnet VPN:: | ||
27 | * File-sharing:: | ||
28 | * The GNU Name System:: | ||
29 | * reclaimID Identity Provider:: | ||
30 | * Using the Virtual Public Network:: | ||
31 | * Using the GNUnet Messenger:: | ||
32 | @end menu | ||
33 | |||
34 | @node Start and stop GNUnet | ||
35 | @section Start and stop GNUnet | ||
36 | |||
37 | Prior to using any GNUnet-based application, one has to start a node: | ||
38 | |||
39 | @example | ||
40 | $ gnunet-arm -s -l gnunet.log | ||
41 | @end example | ||
42 | |||
43 | To stop GNUnet: | ||
44 | |||
45 | @example | ||
46 | $ gnunet-arm -e | ||
47 | @end example | ||
48 | |||
49 | @node First steps - Using the GNU Name System | ||
50 | @section First steps - Using the GNU Name System | ||
51 | |||
52 | |||
53 | @menu | ||
54 | * Preliminaries:: | ||
55 | * Managing Egos:: | ||
56 | * The GNS Tab:: | ||
57 | * Creating a Record:: | ||
58 | * Resolving GNS records:: | ||
59 | * Integration with Browsers:: | ||
60 | * Creating a Business Card:: | ||
61 | * Be Social:: | ||
62 | * Backup of Identities and Egos:: | ||
63 | * Revocation:: | ||
64 | * What's Next?:: | ||
65 | @end menu | ||
66 | |||
67 | @node Preliminaries | ||
68 | @subsection Preliminaries | ||
69 | |||
70 | |||
71 | ``.pin'' is a default zone which points to a zone managed by gnunet.org. | ||
72 | Use @code{gnunet-config -s gns} to view the GNS configuration, including | ||
73 | all configured zones that are operated by other users. The respective | ||
74 | configuration entry names start with a ``.'', e.g. ``.pin''. | ||
75 | |||
76 | You can configure any number of top-level domains, and point them to | ||
77 | the respective zones of your friends! For this, simply obtain the | ||
78 | respective public key (you will learn how below) and extend the | ||
79 | configuration: | ||
80 | |||
81 | @example | ||
82 | $ gnunet-config -s gns -o .myfriend -V PUBLIC_KEY | ||
83 | @end example | ||
84 | |||
85 | @node Managing Egos | ||
86 | @subsection Managing Egos | ||
87 | |||
88 | In GNUnet, identity management is about managing egos. Egos can | ||
89 | correspond to pseudonyms or real-world identities. If you value your | ||
90 | privacy, you are encouraged to use separate egos for separate | ||
91 | activities. | ||
92 | |||
93 | Technically, an ego is first of all a public-private key pair, and | ||
94 | thus egos also always correspond to a GNS zone. Egos are managed by | ||
95 | the IDENTITY service. Note that this service has nothing to do with | ||
96 | the peer identity. The IDENTITY service essentially stores the | ||
97 | private keys under human-readable names, and keeps a mapping of which | ||
98 | private key should be used for particular important system functions. | ||
99 | The existing identities can be listed using the command | ||
100 | @command{gnunet-identity --display} | ||
101 | |||
102 | @example | ||
103 | gnu - JTDVJC69NHU6GQS4B5721MV8VM7J6G2DVRGJV0ONIT6QH7OI6D50 | ||
104 | rules - GO0T87F9BPMF8NKD5A54L2AH1T0GRML539TPFSRMCEA98182QD30 | ||
105 | @end example | ||
106 | |||
107 | |||
108 | @node The GNS Tab | ||
109 | @subsection The GNS Tab | ||
110 | |||
111 | |||
112 | Maintaining your zones is through the NAMESTORE service and is discussed | ||
113 | here. You can manage your zone using @command{gnunet-identity} and | ||
114 | @command{gnunet-namestore}, or most conveniently using | ||
115 | @command{gnunet-namestore-gtk}. | ||
116 | |||
117 | We will use the GTK+ interface in this introduction. Please start | ||
118 | @command{gnunet-gkt} and switch to the GNS tab, which is the tab in | ||
119 | the middle with the letters "GNS" connected by a graph. | ||
120 | |||
121 | Next to the ``Add'' button there is a field where you can enter the | ||
122 | label (pseudonym in IDENTITY subsystem speak) of a zone you would like | ||
123 | to create. Pushing the ``Add'' button will create the zone. | ||
124 | Afterwards, you can change the label in the combo box below at any | ||
125 | time. The label will be the top-level domain that the GNU Name System | ||
126 | will resolve using your zone. For the label, you should pick | ||
127 | a name by which you would like to | ||
128 | be known by your friends (or colleagues). You should pick a label that | ||
129 | is reasonably unique within your social group. Be aware that | ||
130 | the label will be published together with every record in that zone. | ||
131 | |||
132 | Once you have created a first zone, you should see a QR code for the | ||
133 | zone on the right. Next to it is a "Copy" button to copy the public | ||
134 | key string to the clipboard. You can also save the QR code image to | ||
135 | disk. | ||
136 | |||
137 | Furthermore, you now can see the bottom part of the dialog. The | ||
138 | bottom of the window contains the existing entries in the selected zone. | ||
139 | |||
140 | @node Creating a Record | ||
141 | @subsection Creating a Record | ||
142 | |||
143 | |||
144 | We will begin by creating a simple record in your master zone. | ||
145 | To do this, click on the text "<new name>" in the table. The field is | ||
146 | editable, allowing you to enter a fresh label. Labels are restricted | ||
147 | to 63 characters and must not contain dots. For now, simply enter | ||
148 | "test", then press ENTER to confirm. This will create a new (empty) | ||
149 | record group under the label "test". Now click on "<new record>" next | ||
150 | to the new label "test". In the drop-down menu, select "A" and push | ||
151 | ENTER to confirm. Afterwards, a new dialog will pop up, asking to enter | ||
152 | details for the "A" record. | ||
153 | |||
154 | "A" records are used in the @dfn{Domain Name System} (DNS) to specify | ||
155 | IPv4 addresses. An IPv4 address is a number that is used to identify | ||
156 | and address a computer on the Internet (version 4). Please enter | ||
157 | "217.92.15.146" in the dialog below "Destination IPv4 Address" and | ||
158 | select "Record is public". Do not change any of the other options. | ||
159 | Note that as you enter a (well-formed) IPv4 address, the "Save" | ||
160 | button in the bottom right corner becomes sensitive. In general, buttons | ||
161 | in dialogs are often insensitive as long as the contents of the dialog | ||
162 | are incorrect. | ||
163 | |||
164 | Once finished, press the "Save" button. Back in the main dialog, select | ||
165 | the tiny triangle left of the "test" label. By doing so, you get to see | ||
166 | all of the records under "test". Note that you can right-click a record | ||
167 | to edit it later. | ||
168 | |||
169 | |||
170 | @node Resolving GNS records | ||
171 | @subsection Resolving GNS records | ||
172 | |||
173 | |||
174 | Next, you should try resolving your own GNS records. The method we | ||
175 | found to be the most uncomplicated is to do this by explicitly | ||
176 | resolving using @code{gnunet-gns}. For this exercise, we will assume | ||
177 | that you used the string ``gnu'' for the pseudonym (or label) of your | ||
178 | GNS zone. If you used something else, replace ``.gnu'' with your real | ||
179 | pseudonym in the examples below. | ||
180 | |||
181 | In the shell, type: | ||
182 | |||
183 | @example | ||
184 | $ gnunet-gns -u test.gnu # what follows is the reply | ||
185 | test.gnu: | ||
186 | Got `A' record: 217.92.15.146 | ||
187 | @end example | ||
188 | |||
189 | @noindent | ||
190 | That shows that resolution works, once GNS is integrated with | ||
191 | the application. | ||
192 | |||
193 | @node Integration with Browsers | ||
194 | @subsection Integration with Browsers | ||
195 | |||
196 | |||
197 | While we recommend integrating GNS using the NSS module in the | ||
198 | GNU libc Name Service Switch, you can also integrate GNS | ||
199 | directly with your browser via the @code{gnunet-gns-proxy}. | ||
200 | This method can have the advantage that the proxy can validate | ||
201 | TLS/X.509 records and thus strengthen web security; however, the proxy | ||
202 | is still a bit brittle, so expect subtle failures. We have had reasonable | ||
203 | success with Chromium, and various frustrations with Firefox in this area | ||
204 | recently. | ||
205 | |||
206 | The first step is to start the proxy. As the proxy is (usually) | ||
207 | not started by default, this is done as a unprivileged user | ||
208 | using @command{gnunet-arm -i gns-proxy}. Use @command{gnunet-arm -I} | ||
209 | as a unprivileged user to check that the proxy was actually | ||
210 | started. (The most common error for why the proxy may fail to start | ||
211 | is that you did not run @command{gnunet-gns-proxy-setup-ca} during | ||
212 | installation.) The proxy is a SOCKS5 proxy running (by default) | ||
213 | on port 7777. Thus, you need to now configure your browser to use | ||
214 | this proxy. With Chromium, you can do this by starting the browser | ||
215 | as a unprivileged user using | ||
216 | @command{chromium --proxy-server="socks5://localhost:7777"} | ||
217 | For @command{Firefox} (or @command{Icecat}), select "Edit-Preferences" | ||
218 | in the menu, and then select the "Advanced" tab in the dialog | ||
219 | and then "Network": | ||
220 | |||
221 | Here, select "Settings..." to open the proxy settings dialog. | ||
222 | Select "Manual proxy configuration" and enter @code{localhost} | ||
223 | with port 7777 under SOCKS Host. Furthermore, set the | ||
224 | checkbox ``Proxy DNS when using SOCKS v5'' at the bottom of | ||
225 | the dialog. Finally, push "OK". | ||
226 | |||
227 | You must also go to about:config and change the | ||
228 | @code{browser.fixup.alternate.enabled} option to @code{false}, | ||
229 | otherwise the browser will autoblunder an address like | ||
230 | @code{@uref{http://www.gnu/, www.gnu}} to | ||
231 | @code{@uref{http://www.gnu.com/, www.gnu.com}}. If you want | ||
232 | to resolve @@ in your own TLDs, you must additionally | ||
233 | set @code{browser.fixup.dns_first_use_for_single_words} to @code{true}. | ||
234 | |||
235 | After configuring your browser, you might want to first confirm that it | ||
236 | continues to work as before. (The proxy is still experimental and if you | ||
237 | experience "odd" failures with some webpages, you might want to disable | ||
238 | it again temporarily.) Next, test if things work by typing | ||
239 | "@uref{http://test.gnu/}" into the URL bar of your browser. | ||
240 | This currently fails with (my version of) Firefox as Firefox is | ||
241 | super-smart and tries to resolve "@uref{http://www.test.gnu/}" instead of | ||
242 | "@uref{test.gnu}". Chromium can be convinced to comply if you explicitly | ||
243 | include the "http://" prefix --- otherwise a Google search might be | ||
244 | attempted, which is not what you want. If successful, you should | ||
245 | see a simple website. | ||
246 | |||
247 | Note that while you can use GNS to access ordinary websites, this is | ||
248 | more an experimental feature and not really our primary goal at this | ||
249 | time. Still, it is a possible use-case and we welcome help with testing | ||
250 | and development. | ||
251 | |||
252 | @pindex gnunet-bcd | ||
253 | @node Creating a Business Card | ||
254 | @subsection Creating a Business Card | ||
255 | @c FIXME: Which parts of texlive are needed? Some systems offer a modular | ||
256 | @c texlive (smaller size). | ||
257 | Before we can really use GNS, you should create a business card. | ||
258 | Note that this requires having @command{LaTeX} installed on your system. | ||
259 | If you are using a Debian GNU/Linux based operating system, the | ||
260 | following command should install the required components. | ||
261 | Keep in mind that this @b{requires 3GB} of downloaded data and possibly | ||
262 | @b{even more} when unpacked. On a GNU Guix based system texlive 2017 has | ||
263 | returns a DAG size of 5032.4 MiB. | ||
264 | The packages which are confirmed to be required are: | ||
265 | |||
266 | @itemize @bullet | ||
267 | @item texlive-units | ||
268 | @item texlive-labels | ||
269 | @item texlive-pst-barcode | ||
270 | @item texlive-luatex85 | ||
271 | @item texlive-preview | ||
272 | @item texlive-pdfcrop | ||
273 | @item texlive-koma-script | ||
274 | @end itemize | ||
275 | |||
276 | |||
277 | @b{We welcome any help in identifying the required components of the | ||
278 | TexLive Distribution. This way we could just state the required components | ||
279 | without pulling in the full distribution of TexLive.} | ||
280 | |||
281 | @example | ||
282 | apt-get install texlive-full | ||
283 | @end example | ||
284 | |||
285 | @noindent | ||
286 | Start creating a business card by clicking the "Copy" button | ||
287 | in @command{gnunet-namestore-gtk}. Next, you should start | ||
288 | the @command{gnunet-bcd} program (in the terminal, on the command-line). | ||
289 | You do not need to pass any options, and please be not surprised if | ||
290 | there is no output: | ||
291 | |||
292 | @example | ||
293 | $ gnunet-bcd # seems to hang... | ||
294 | @end example | ||
295 | |||
296 | @noindent | ||
297 | Then, start a browser and point it to @uref{http://localhost:8888/} | ||
298 | where @code{gnunet-bcd} is running a Web server! | ||
299 | |||
300 | First, you might want to fill in the "GNS Public Key" field by | ||
301 | right-clicking and selecting "Paste", filling in the public key | ||
302 | from the copy you made in @command{gnunet-namestore-gtk}. | ||
303 | Then, fill in all of the other fields, including your @b{GNS NICKname}. | ||
304 | Adding a GPG fingerprint is optional. | ||
305 | Once finished, click "Submit Query". | ||
306 | If your @code{LaTeX} installation is incomplete, the result will be | ||
307 | disappointing. | ||
308 | Otherwise, you should get a PDF containing fancy 5x2 double-sided | ||
309 | translated business cards with a QR code containing your public key | ||
310 | and a GNUnet logo. | ||
311 | We'll explain how to use those a bit later. | ||
312 | You can now go back to the shell running @code{gnunet-bcd} and press | ||
313 | @b{CTRL-C} to shut down the Web server. | ||
314 | |||
315 | |||
316 | @node Be Social | ||
317 | @subsection Be Social | ||
318 | |||
319 | |||
320 | Next, you should print out your business card and be social. | ||
321 | Find a friend, help them install GNUnet and exchange business cards with | ||
322 | them. Or, if you're a desperate loner, you might try the next step with | ||
323 | your own card. Still, it'll be hard to have a conversation with | ||
324 | yourself later, so it would be better if you could find a friend. | ||
325 | You might also want a camera attached to your computer, so | ||
326 | you might need a trip to the store together. | ||
327 | |||
328 | Before we get started, we need to tell @code{gnunet-qr} which zone | ||
329 | it should import new records into. For this, run: | ||
330 | |||
331 | @pindex gnunet-identity | ||
332 | @example | ||
333 | $ gnunet-identity -s namestore -e NAME | ||
334 | @end example | ||
335 | where NAME is the name of the zone you want to import records | ||
336 | into. In our running example, this would be ``gnu''. | ||
337 | |||
338 | @pindex gnunet-qr | ||
339 | Henceforth, for every business card you collect, simply run: | ||
340 | @example | ||
341 | $ gnunet-qr | ||
342 | @end example | ||
343 | |||
344 | @noindent | ||
345 | to open a window showing whatever your camera points at. | ||
346 | Hold up your friend's business card and tilt it until | ||
347 | the QR code is recognized. At that point, the window should | ||
348 | automatically close. At that point, your friend's NICKname and their | ||
349 | public key should have been automatically imported into your zone. | ||
350 | |||
351 | Assuming both of your peers are properly integrated in the | ||
352 | GNUnet network at this time, you should thus be able to | ||
353 | resolve your friends names. Suppose your friend's nickname | ||
354 | is "Bob". Then, type | ||
355 | |||
356 | @pindex gnunet-gns | ||
357 | @example | ||
358 | $ gnunet-gns -u test.bob.gnu | ||
359 | @end example | ||
360 | |||
361 | @noindent | ||
362 | to check if your friend was as good at following instructions | ||
363 | as you were. | ||
364 | |||
365 | |||
366 | @node Backup of Identities and Egos | ||
367 | @subsection Backup of Identities and Egos | ||
368 | |||
369 | |||
370 | One should always backup their files, especially in these SSD days (our | ||
371 | team has suffered 3 SSD crashes over a span of 2 weeks). Backing up peer | ||
372 | identity and zones is achieved by copying the following files: | ||
373 | |||
374 | The peer identity file can be found | ||
375 | in @file{~/.local/share/gnunet/private_key.ecc} | ||
376 | |||
377 | The private keys of your egos are stored in the | ||
378 | directory @file{~/.local/share/gnunet/identity/egos/}. | ||
379 | They are stored in files whose filenames correspond to the zones' | ||
380 | ego names. These are probably the most important files you want | ||
381 | to backup from a GNUnet installation. | ||
382 | |||
383 | Note: All these files contain cryptographic keys and they are | ||
384 | stored without any encryption. So it is advisable to backup | ||
385 | encrypted copies of them. | ||
386 | |||
387 | |||
388 | @node Revocation | ||
389 | @subsection Revocation | ||
390 | |||
391 | Now, in the situation of an attacker gaining access to the private key of | ||
392 | one of your egos, the attacker can create records in the respective | ||
393 | GNS zone | ||
394 | and publish them as if you published them. Anyone resolving your | ||
395 | domain will get these new records and when they verify they seem | ||
396 | authentic because the attacker has signed them with your key. | ||
397 | |||
398 | To address this potential security issue, you can pre-compute | ||
399 | a revocation certificate corresponding to your ego. This certificate, | ||
400 | when published on the P2P network, flags your private key as invalid, | ||
401 | and all further resolutions or other checks involving the key will fail. | ||
402 | |||
403 | @pindex gnunet-revocation | ||
404 | A revocation certificate is thus a useful tool when things go out of | ||
405 | control, but at the same time it should be stored securely. | ||
406 | Generation of the revocation certificate for a zone can be done through | ||
407 | @command{gnunet-revocation}. For example, the following command (as | ||
408 | unprivileged user) generates a revocation file | ||
409 | @file{revocation.dat} for the zone @code{zone1}: | ||
410 | @command{gnunet-revocation -f revocation.dat -R zone1} | ||
411 | |||
412 | The above command only pre-computes a revocation certificate. It does | ||
413 | not revoke the given zone. Pre-computing a revocation certificate | ||
414 | involves computing a proof-of-work and hence may take up to 4 to 5 days | ||
415 | on a modern processor. Note that you can abort and resume the | ||
416 | calculation at any time. Also, even if you did not finish the | ||
417 | calculation, the resulting file will contain the signature, which is | ||
418 | sufficient to complete the revocation process even without access to | ||
419 | the private key. So instead of waiting for a few days, you can just | ||
420 | abort with CTRL-C, backup the revocation certificate and run the | ||
421 | calculation only if your key actually was compromised. This has the | ||
422 | disadvantage of revocation taking longer after the incident, but | ||
423 | the advantage of saving a significant amount of energy. So unless | ||
424 | you believe that a key compromise will need a rapid response, we | ||
425 | urge you to wait with generating the revocation certificate. | ||
426 | Also, the calculation is deliberately expensive, to deter people from | ||
427 | doing this just for fun (as the actual revocation operation is expensive | ||
428 | for the network, not for the peer performing the revocation). | ||
429 | |||
430 | |||
431 | @c FIXME: The Manual should give away the command using an example that is | ||
432 | @c very likely to never exist. | ||
433 | To avoid TL;DR ones from accidentally revocating their zones, we are not | ||
434 | giving away the command, but it is uncomplicated: the actual revocation is | ||
435 | performed by using the @command{-p} option of @command{gnunet-revocation}. | ||
436 | |||
437 | |||
438 | @node What's Next? | ||
439 | @subsection What's Next? | ||
440 | |||
441 | |||
442 | This may seem not like much of an application yet, but you have | ||
443 | just been one of the first to perform a decentralized secure name | ||
444 | lookup (where nobody could have altered the value supplied by your | ||
445 | friend) in a privacy-preserving manner (your query on the network | ||
446 | and the corresponding response were always encrypted). So what | ||
447 | can you really do with this? Well, to start with, you can publish your | ||
448 | GnuPG fingerprint in GNS as a "CERT" record and replace the public | ||
449 | web-of-trust with its complicated trust model with explicit names | ||
450 | and privacy-preserving resolution. Also, you should read the next | ||
451 | chapter of the tutorial and learn how to use GNS to have a | ||
452 | private conversation with your friend. Finally, help us | ||
453 | with the next GNUnet release for even more applications | ||
454 | using this new public key infrastructure. | ||
455 | |||
456 | @pindex gnunet-conservation-gtk | ||
457 | @node First steps - Using GNUnet Conversation | ||
458 | @section First steps - Using GNUnet Conversation | ||
459 | |||
460 | |||
461 | First, you should launch the graphical user interface. You can do | ||
462 | this from the command-line by typing | ||
463 | |||
464 | @example | ||
465 | $ gnunet-conversation-gtk | ||
466 | @end example | ||
467 | |||
468 | @menu | ||
469 | * Testing your Audio Equipment:: | ||
470 | * GNS Zones:: | ||
471 | @end menu | ||
472 | |||
473 | @node Testing your Audio Equipment | ||
474 | @subsection Testing your Audio Equipment | ||
475 | |||
476 | |||
477 | First, you should use @code{gnunet-conversation-test} to check that your | ||
478 | microphone and speaker are working correctly. You will be prompted to | ||
479 | speak for 5 seconds, and then those 5 seconds will be replayed to you. | ||
480 | The network is not involved in this test. If it fails, you should run | ||
481 | your pulse audio configuration tool to check that microphone and | ||
482 | speaker are not muted and, if you have multiple input/output devices, | ||
483 | that the correct device is being associated with GNUnet's audio tools. | ||
484 | |||
485 | @node GNS Zones | ||
486 | @subsection GNS Zones | ||
487 | |||
488 | |||
489 | @code{gnunet-conversation} uses GNS for addressing. This means that | ||
490 | you need to have a GNS zone created before using it. Information | ||
491 | about how to create GNS zones can be found here. | ||
492 | |||
493 | |||
494 | @menu | ||
495 | * Picking an Identity:: | ||
496 | * Calling somebody:: | ||
497 | @end menu | ||
498 | |||
499 | @node Picking an Identity | ||
500 | @subsubsection Picking an Identity | ||
501 | |||
502 | |||
503 | To make a call with @code{gnunet-conversation}, you first | ||
504 | need to choose an identity. This identity is both the caller ID | ||
505 | that will show up when you call somebody else, as well as the | ||
506 | GNS zone that will be used to resolve names of users that you | ||
507 | are calling. Run | ||
508 | |||
509 | @pindex gnunet-conversation | ||
510 | @example | ||
511 | gnunet-conversation -e zone-name | ||
512 | @end example | ||
513 | |||
514 | @noindent | ||
515 | to start the command-line tool. You will see a message saying | ||
516 | that your phone is now "active on line 0". You can connect | ||
517 | multiple phones on different lines at the same peer. For the | ||
518 | first phone, the line zero is of course a fine choice. | ||
519 | |||
520 | Next, you should type in @command{/help} for a list of | ||
521 | available commands. We will explain the important ones | ||
522 | during this tutorial. First, you will need to type in | ||
523 | @command{/address} to determine the address of your | ||
524 | phone. The result should look something like this: | ||
525 | |||
526 | @example | ||
527 | /address | ||
528 | 0-PD67SGHF3E0447TU9HADIVU9OM7V4QHTOG0EBU69TFRI2LG63DR0 | ||
529 | @end example | ||
530 | |||
531 | @noindent | ||
532 | Here, the "0" is your phone line, and what follows | ||
533 | after the hyphen is your peer's identity. This information will | ||
534 | need to be placed in a PHONE record of | ||
535 | your GNS master-zone so that other users can call you. | ||
536 | |||
537 | Start @code{gnunet-namestore-gtk} now (possibly from another | ||
538 | shell) and create an entry home-phone in your master zone. | ||
539 | For the record type, select PHONE. You should then see the | ||
540 | PHONE dialog: | ||
541 | |||
542 | @image{images/gnunet-namestore-gtk-phone,5in,,Dialog to publish a PHONE record} | ||
543 | |||
544 | Note: Do not choose the expiry time to be 'Never'. If you | ||
545 | do that, you assert that this record will never change and | ||
546 | can be cached indefinitely by the DHT and the peers which | ||
547 | resolve this record. A reasonable period is 1 year. | ||
548 | |||
549 | Enter your peer identity under Peer and leave the line | ||
550 | at zero. Select the first option to make the record public. | ||
551 | If you entered your peer identity incorrectly, | ||
552 | the "Save" button will not work; you might want to use | ||
553 | copy-and-paste instead of typing in the peer identity | ||
554 | manually. Save the record. | ||
555 | |||
556 | @node Calling somebody | ||
557 | @subsubsection Calling somebody | ||
558 | |||
559 | |||
560 | Now you can call a buddy. Obviously, your buddy will have to have GNUnet | ||
561 | installed and must have performed the same steps. Also, you must have | ||
562 | your buddy in your GNS master zone, for example by having imported | ||
563 | your buddy's public key using @code{gnunet-qr}. Suppose your buddy | ||
564 | is in your zone as @code{buddy.mytld} and they also created their | ||
565 | phone using a label "home-phone". Then you can initiate a call using: | ||
566 | |||
567 | @example | ||
568 | /call home-phone.buddy.mytld | ||
569 | @end example | ||
570 | |||
571 | It may take some time for GNUnet to resolve the name and to establish | ||
572 | a link. If your buddy has your public key in their master zone, they | ||
573 | should see an incoming call with your name. If your public key is not | ||
574 | in their master zone, they will just see the public key as the caller ID. | ||
575 | |||
576 | Your buddy then can answer the call using the "/accept" command. After | ||
577 | that, (encrypted) voice data should be relayed between your two peers. | ||
578 | Either of you can end the call using @command{/cancel}. You can exit | ||
579 | @code{gnunet-conversation} using @command{/quit}. | ||
580 | |||
581 | |||
582 | @node First steps - Using the GNUnet VPN | ||
583 | @section First steps - Using the GNUnet VPN | ||
584 | |||
585 | |||
586 | |||
587 | @menu | ||
588 | * VPN Preliminaries:: | ||
589 | * GNUnet-Exit configuration:: | ||
590 | * GNS configuration:: | ||
591 | * Accessing the service:: | ||
592 | * Using a Browser:: | ||
593 | @end menu | ||
594 | |||
595 | @node VPN Preliminaries | ||
596 | @subsection VPN Preliminaries | ||
597 | |||
598 | |||
599 | To test the GNUnet VPN, we should first run a web server. | ||
600 | The easiest way to do this is to just start @code{gnunet-bcd}, | ||
601 | which will run a webserver on port @code{8888} by default. | ||
602 | Naturally, you can run some other HTTP server for our little tutorial. | ||
603 | |||
604 | If you have not done this, you should also configure your | ||
605 | Name System Service switch to use GNS. In your @code{/etc/nsswitch.conf} | ||
606 | you should fine a line like this: | ||
607 | |||
608 | @example | ||
609 | hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 | ||
610 | @end example | ||
611 | |||
612 | @noindent | ||
613 | The exact details may differ a bit, which is fine. Add the text | ||
614 | @code{gns [NOTFOUND=return]} after @code{files}: | ||
615 | |||
616 | @example | ||
617 | hosts: files gns [NOTFOUND=return] mdns4_minimal [NOTFOUND=return] dns mdns4 | ||
618 | @end example | ||
619 | |||
620 | @c TODO: outdated section, we no longer install this as part of the | ||
621 | @c TODO: standard installation procedure and should point out the manual | ||
622 | @c TODO: steps required to make it useful. | ||
623 | @noindent | ||
624 | You might want to make sure that @code{/lib/libnss_gns.so.2} exists on | ||
625 | your system, it should have been created during the installation. | ||
626 | If not, re-run | ||
627 | |||
628 | @example | ||
629 | $ configure --with-nssdir=/lib | ||
630 | $ cd src/gns/nss; sudo make install | ||
631 | @end example | ||
632 | |||
633 | @noindent | ||
634 | to install the NSS plugins in the proper location. | ||
635 | |||
636 | @node GNUnet-Exit configuration | ||
637 | @subsection GNUnet-Exit configuration | ||
638 | |||
639 | |||
640 | Stop your peer (as user @code{gnunet}, run @command{gnunet-arm -e}) and | ||
641 | run @command{gnunet-setup}. In @command{gnunet-setup}, make sure to | ||
642 | activate the @strong{EXIT} and @strong{GNS} services in the General tab. | ||
643 | Then select the Exit tab. Most of the defaults should be fine (but | ||
644 | you should check against the screenshot that they have not been modified). | ||
645 | In the bottom area, enter @code{bcd} under Identifier and change the | ||
646 | Destination to @code{169.254.86.1:8888} (if your server runs on a port | ||
647 | other than 8888, change the 8888 port accordingly). | ||
648 | |||
649 | Now exit @command{gnunet-setup} and restart your peer | ||
650 | (@command{gnunet-arm -s}). | ||
651 | |||
652 | @node GNS configuration | ||
653 | @subsection GNS configuration | ||
654 | |||
655 | |||
656 | Now, using your normal user (not the @code{gnunet} system user), run | ||
657 | @command{gnunet-namestore-gtk}. Add a new label www in your | ||
658 | master zone. For the record type, select @code{VPN}. You should then | ||
659 | see the VPN dialog: | ||
660 | |||
661 | @image{images/gnunet-namestore-gtk-vpn,5in,,Dialog to publish a VPN record} | ||
662 | |||
663 | Under peer, you need to supply the peer identity of your own peer. You can | ||
664 | obtain the respective string by running @command{gnunet-peerinfo -sq} | ||
665 | as the @code{gnunet} user. For the Identifier, you need to supply the same | ||
666 | identifier that we used in the Exit setup earlier, so here supply "bcd". | ||
667 | If you want others to be able to use the service, you should probably make | ||
668 | the record public. For non-public services, you should use a passphrase | ||
669 | instead of the string "bcd". Save the record and | ||
670 | exit @command{gnunet-namestore-gtk}. | ||
671 | |||
672 | @node Accessing the service | ||
673 | @subsection Accessing the service | ||
674 | |||
675 | |||
676 | You should now be able to access your webserver. Type in: | ||
677 | |||
678 | @example | ||
679 | $ wget http://www.gnu/ | ||
680 | @end example | ||
681 | |||
682 | @noindent | ||
683 | The request will resolve to the VPN record, telling the GNS resolver | ||
684 | to route it via the GNUnet VPN. The GNS resolver will ask the | ||
685 | GNUnet VPN for an IPv4 address to return to the application. The | ||
686 | VPN service will use the VPN information supplied by GNS to create | ||
687 | a tunnel (via GNUnet's MESH service) to the EXIT peer. | ||
688 | At the EXIT, the name "bcd" and destination port (80) will be mapped | ||
689 | to the specified destination IP and port. While all this is currently | ||
690 | happening on just the local machine, it should also work with other | ||
691 | peers --- naturally, they will need a way to access your GNS zone | ||
692 | first, for example by learning your public key from a QR code on | ||
693 | your business card. | ||
694 | |||
695 | @node Using a Browser | ||
696 | @subsection Using a Browser | ||
697 | |||
698 | |||
699 | Sadly, modern browsers tend to bypass the Name Services Switch and | ||
700 | attempt DNS resolution directly. You can either run | ||
701 | a @code{gnunet-dns2gns} DNS proxy, or point the browsers to an | ||
702 | HTTP proxy. When we tried it, Iceweasel did not like to connect to | ||
703 | the socks proxy for @code{.gnu} TLDs, even if we disabled its | ||
704 | autoblunder of changing @code{.gnu} to ".gnu.com". Still, | ||
705 | using the HTTP proxy with Chrome does work. | ||
706 | |||
707 | @node File-sharing | ||
708 | @section File-sharing | ||
709 | |||
710 | |||
711 | This chapter documents the GNUnet file-sharing application. The original | ||
712 | file-sharing implementation for GNUnet was designed to provide | ||
713 | @strong{anonymous} file-sharing. However, over time, we have also added | ||
714 | support for non-anonymous file-sharing (which can provide better | ||
715 | performance). Anonymous and non-anonymous file-sharing are quite | ||
716 | integrated in GNUnet and, except for routing, share most of the concepts | ||
717 | and implementation. There are three primary file-sharing operations: | ||
718 | publishing, searching and downloading. For each of these operations, | ||
719 | the user specifies an @strong{anonymity level}. If both the publisher and | ||
720 | the searcher/downloader specify "no anonymity", non-anonymous | ||
721 | file-sharing is used. If either user specifies some desired degree | ||
722 | of anonymity, anonymous file-sharing will be used. | ||
723 | |||
724 | After a short introduction, we will first look at the various concepts | ||
725 | in GNUnet's file-sharing implementation. Then, we will discuss | ||
726 | specifics as to how they impact users that publish, search or download | ||
727 | files. | ||
728 | |||
729 | |||
730 | @menu | ||
731 | * fs-Searching:: | ||
732 | * fs-Downloading:: | ||
733 | * fs-Publishing:: | ||
734 | * fs-Concepts:: | ||
735 | * Namespace Management:: | ||
736 | * File-Sharing URIs:: | ||
737 | * GTK User Interface:: | ||
738 | @end menu | ||
739 | |||
740 | @node fs-Searching | ||
741 | @subsection Searching | ||
742 | |||
743 | |||
744 | The command @command{gnunet-search} can be used to search | ||
745 | for content on GNUnet. The format is: | ||
746 | |||
747 | @example | ||
748 | $ gnunet-search [-t TIMEOUT] KEYWORD | ||
749 | @end example | ||
750 | |||
751 | @noindent | ||
752 | The @command{-t} option specifies that the query should timeout after | ||
753 | approximately TIMEOUT seconds. A value of zero (``0'') is interpreted | ||
754 | as @emph{no timeout}, which is the default. In this case, | ||
755 | @command{gnunet-search} will never terminate (unless you press | ||
756 | @command{CTRL-C}). | ||
757 | |||
758 | If multiple words are passed as keywords, they will all be | ||
759 | considered optional. Prefix keywords with a "+" to make them mandatory. | ||
760 | |||
761 | Note that searching using | ||
762 | |||
763 | @example | ||
764 | $ gnunet-search Das Kapital | ||
765 | @end example | ||
766 | |||
767 | @noindent | ||
768 | is not the same as searching for | ||
769 | |||
770 | @example | ||
771 | $ gnunet-search "Das Kapital" | ||
772 | @end example | ||
773 | |||
774 | @noindent | ||
775 | as the first will match files shared under the keywords | ||
776 | "Das" or "Kapital" whereas the second will match files | ||
777 | shared under the keyword "Das Kapital". | ||
778 | |||
779 | Search results are printed by @command{gnunet-search} like this: | ||
780 | |||
781 | @c it will be better the avoid the ellipsis altogether because I don't | ||
782 | @c understand the explanation below that | ||
783 | @c ng0: who is ``I'' and what was the complete sentence? | ||
784 | @example | ||
785 | #15: | ||
786 | gnunet-download -o "COPYING" gnunet://fs/chk/PGK8M...3EK130.75446 | ||
787 | |||
788 | @end example | ||
789 | |||
790 | @noindent | ||
791 | The whole line is the command you would have to enter to download | ||
792 | the file. The first argument passed to @code{-o} is the suggested | ||
793 | filename (you may change it to whatever you like). | ||
794 | It is followed by the key for decrypting the file, the query for | ||
795 | searching the file, a checksum (in hexadecimal) finally the size of | ||
796 | the file in bytes. | ||
797 | |||
798 | @node fs-Downloading | ||
799 | @subsection Downloading | ||
800 | |||
801 | |||
802 | In order to download a file, you need the whole line returned by | ||
803 | @command{gnunet-search}. | ||
804 | You can then use the tool @command{gnunet-download} to obtain the file: | ||
805 | |||
806 | @example | ||
807 | $ gnunet-download -o <FILENAME> <GNUNET-URL> | ||
808 | @end example | ||
809 | |||
810 | @noindent | ||
811 | FILENAME specifies the name of the file where GNUnet is supposed | ||
812 | to write the result. Existing files are overwritten. If the | ||
813 | existing file contains blocks that are identical to the | ||
814 | desired download, those blocks will not be downloaded again | ||
815 | (automatic resume). | ||
816 | |||
817 | If you want to download the GPL from the previous example, | ||
818 | you do the following: | ||
819 | |||
820 | @example | ||
821 | $ gnunet-download -o "COPYING" gnunet://fs/chk/PGK8M...3EK130.75446 | ||
822 | @end example | ||
823 | |||
824 | @noindent | ||
825 | If you ever have to abort a download, you can continue it at any time by | ||
826 | re-issuing @command{gnunet-download} with the same filename. | ||
827 | In that case, GNUnet will @strong{not} download blocks again that are | ||
828 | already present. | ||
829 | |||
830 | GNUnet's file-encoding mechanism will ensure file integrity, even if the | ||
831 | existing file was not downloaded from GNUnet in the first place. | ||
832 | |||
833 | You may want to use the @command{-V} switch to turn on verbose | ||
834 | reporting. In this case, @command{gnunet-download} will print the | ||
835 | current number of bytes downloaded whenever new data was received. | ||
836 | |||
837 | @node fs-Publishing | ||
838 | @subsection Publishing | ||
839 | |||
840 | |||
841 | The command @command{gnunet-publish} can be used to add content | ||
842 | to the network. The basic format of the command is | ||
843 | |||
844 | @example | ||
845 | $ gnunet-publish [-n] [-k KEYWORDS]* [-m TYPE:VALUE] FILENAME | ||
846 | @end example | ||
847 | |||
848 | For example | ||
849 | @example | ||
850 | $ gnunet-publish -m "description:GNU License" -k gpl -k test -m "mimetype:text/plain" COPYING | ||
851 | @end example | ||
852 | |||
853 | @menu | ||
854 | * Important command-line options:: | ||
855 | * Indexing vs. Inserting:: | ||
856 | @end menu | ||
857 | |||
858 | @node Important command-line options | ||
859 | @subsubsection Important command-line options | ||
860 | |||
861 | |||
862 | The option @code{-k} is used to specify keywords for the file that | ||
863 | should be inserted. You can supply any number of keywords, | ||
864 | and each of the keywords will be sufficient to locate and | ||
865 | retrieve the file. Please note that you must use the @code{-k} option | ||
866 | more than once -- one for each expression you use as a keyword for | ||
867 | the filename. | ||
868 | |||
869 | The -m option is used to specify meta-data, such as descriptions. | ||
870 | You can use -m multiple times. The TYPE passed must be from the | ||
871 | list of meta-data types known to libextractor. You can obtain this | ||
872 | list by running @command{extract -L}. Use quotes around the entire | ||
873 | meta-data argument if the value contains spaces. The meta-data | ||
874 | is displayed to other users when they select which files to | ||
875 | download. The meta-data and the keywords are optional and | ||
876 | may be inferred using @code{GNU libextractor}. | ||
877 | |||
878 | @command{gnunet-publish} has a few additional options to handle | ||
879 | namespaces and directories. Refer to the man-page for details: | ||
880 | |||
881 | @example | ||
882 | man gnunet-publish | ||
883 | @end example | ||
884 | |||
885 | @node Indexing vs. Inserting | ||
886 | @subsubsection Indexing vs Inserting | ||
887 | |||
888 | |||
889 | By default, GNUnet indexes a file instead of making a full copy. | ||
890 | This is much more efficient, but requires the file to stay unaltered | ||
891 | at the location where it was when it was indexed. If you intend to move, | ||
892 | delete or alter a file, consider using the option @code{-n} which will | ||
893 | force GNUnet to make a copy of the file in the database. | ||
894 | |||
895 | Since it is much less efficient, this is strongly discouraged for large | ||
896 | files. When GNUnet indexes a file (default), GNUnet does @strong{not} | ||
897 | create an additional encrypted copy of the file but just computes a | ||
898 | summary (or index) of the file. That summary is approximately two percent | ||
899 | of the size of the original file and is stored in GNUnet's database. | ||
900 | Whenever a request for a part of an indexed file reaches GNUnet, | ||
901 | this part is encrypted on-demand and send out. This way, there is no | ||
902 | need for an additional encrypted copy of the file to stay anywhere | ||
903 | on the drive. This is different from other systems, such as Freenet, | ||
904 | where each file that is put online must be in Freenet's database in | ||
905 | encrypted format, doubling the space requirements if the user wants | ||
906 | to preserve a directly accessible copy in plaintext. | ||
907 | |||
908 | Thus indexing should be used for all files where the user will keep | ||
909 | using this file (at the location given to gnunet-publish) and does | ||
910 | not want to retrieve it back from GNUnet each time. If you want to | ||
911 | remove a file that you have indexed from the local peer, use the tool | ||
912 | @command{gnunet-unindex} to un-index the file. | ||
913 | |||
914 | The option @code{-n} may be used if the user fears that the file might | ||
915 | be found on their drive (assuming the computer comes under the control | ||
916 | of an adversary). When used with the @code{-n} flag, the user has a | ||
917 | much better chance of denying knowledge of the existence of the file, | ||
918 | even if it is still (encrypted) on the drive and the adversary is | ||
919 | able to crack the encryption (e.g. by guessing the keyword. | ||
920 | |||
921 | @node fs-Concepts | ||
922 | @subsection Concepts | ||
923 | |||
924 | |||
925 | For better results with filesharing it is useful to understand the | ||
926 | following concepts. | ||
927 | In addition to anonymous routing GNUnet attempts to give users a better | ||
928 | experience in searching for content. GNUnet uses cryptography to safely | ||
929 | break content into smaller pieces that can be obtained from different | ||
930 | sources without allowing participants to corrupt files. GNUnet makes it | ||
931 | difficult for an adversary to send back bogus search results. GNUnet | ||
932 | enables content providers to group related content and to establish a | ||
933 | reputation. Furthermore, GNUnet allows updates to certain content to be | ||
934 | made available. This section is supposed to introduce users to the | ||
935 | concepts that are used to achieve these goals. | ||
936 | |||
937 | |||
938 | @menu | ||
939 | * Files:: | ||
940 | * Keywords:: | ||
941 | * Directories:: | ||
942 | * Egos and File-Sharing:: | ||
943 | * Namespaces:: | ||
944 | * Advertisements:: | ||
945 | * Anonymity level:: | ||
946 | * Content Priority:: | ||
947 | * Replication:: | ||
948 | @end menu | ||
949 | |||
950 | @node Files | ||
951 | @subsubsection Files | ||
952 | |||
953 | |||
954 | A file in GNUnet is just a sequence of bytes. Any file-format is allowed | ||
955 | and the maximum file size is theoretically @math{2^64 - 1} bytes, except | ||
956 | that it would take an impractical amount of time to share such a file. | ||
957 | GNUnet itself never interprets the contents of shared files, except when | ||
958 | using GNU libextractor to obtain keywords. | ||
959 | |||
960 | @node Keywords | ||
961 | @subsubsection Keywords | ||
962 | |||
963 | |||
964 | Keywords are the most simple mechanism to find files on GNUnet. | ||
965 | Keywords are @strong{case-sensitive} and the search string | ||
966 | must always match @strong{exactly} the keyword used by the | ||
967 | person providing the file. Keywords are never transmitted in | ||
968 | plaintext. The only way for an adversary to determine the keyword | ||
969 | that you used to search is to guess it (which then allows the | ||
970 | adversary to produce the same search request). Since providing | ||
971 | keywords by hand for each shared file is tedious, GNUnet uses | ||
972 | GNU libextractor to help automate this process. Starting a | ||
973 | keyword search on a slow machine can take a little while since | ||
974 | the keyword search involves computing a fresh RSA key to formulate the | ||
975 | request. | ||
976 | |||
977 | @node Directories | ||
978 | @subsubsection Directories | ||
979 | |||
980 | |||
981 | A directory in GNUnet is a list of file identifiers with meta data. | ||
982 | The file identifiers provide sufficient information about the files | ||
983 | to allow downloading the contents. Once a directory has been created, | ||
984 | it cannot be changed since it is treated just like an ordinary file | ||
985 | by the network. Small files (of a few kilobytes) can be inlined in | ||
986 | the directory, so that a separate download becomes unnecessary. | ||
987 | |||
988 | Directories are shared just like ordinary files. If you download a | ||
989 | directory with @command{gnunet-download}, you can use | ||
990 | @command{gnunet-directory} to list its contents. The canonical | ||
991 | extension for GNUnet directories when stored as files in your | ||
992 | local file-system is ".gnd". The contents of a directory are URIs and | ||
993 | meta data. | ||
994 | The URIs contain all the information required by | ||
995 | @command{gnunet-download} to retrieve the file. The meta data | ||
996 | typically includes the mime-type, description, a filename and | ||
997 | other meta information, and possibly even the full original file | ||
998 | (if it was small). | ||
999 | |||
1000 | @node Egos and File-Sharing | ||
1001 | @subsubsection Egos and File-Sharing | ||
1002 | |||
1003 | When sharing files, it is sometimes desirable to build a reputation as | ||
1004 | a source for quality information. With egos, publishers can | ||
1005 | (cryptographically) sign files, thereby demonstrating that various | ||
1006 | files were published by the same entity. An ego thus allows users to | ||
1007 | link different publication events, thereby deliberately reducing | ||
1008 | anonymity to pseudonymity. | ||
1009 | |||
1010 | Egos used in GNUnet's file-sharing for such pseudonymous publishing | ||
1011 | also correspond to the egos used to identify and sign zones in the | ||
1012 | GNU Name System. However, if the same ego is used for file-sharing | ||
1013 | and for a GNS zone, this will weaken the privacy assurances provided | ||
1014 | by the anonymous file-sharing protocol. | ||
1015 | |||
1016 | Note that an ego is NOT bound to a GNUnet peer. There can be multiple | ||
1017 | egos for a single user, and users could (theoretically) share | ||
1018 | the private keys of an ego by copying the respective private keys. | ||
1019 | |||
1020 | |||
1021 | @node Namespaces | ||
1022 | @subsubsection Namespaces | ||
1023 | |||
1024 | A namespace is a set of files that were signed by the same ego. | ||
1025 | Today, namespaces are implemented independently of GNS zones, but | ||
1026 | in the future we plan to merge the two such that a GNS zone can | ||
1027 | basically contain files using a file-sharing specific record type. | ||
1028 | |||
1029 | Files (or directories) that have been signed and placed into a | ||
1030 | namespace can be updated. Updates are identified as authentic if the | ||
1031 | same secret key was used to sign the update. | ||
1032 | |||
1033 | @node Advertisements | ||
1034 | @subsubsection Advertisements | ||
1035 | |||
1036 | Advertisements are used to notify other users about the existence of a | ||
1037 | namespace. Advertisements are propagated using the normal keyword | ||
1038 | search. When an advertisement is received (in response to a search), | ||
1039 | the namespace is added to the list of namespaces available in the | ||
1040 | namespace-search dialogs of gnunet-fs-gtk and printed by | ||
1041 | @code{gnunet-identity}. Whenever a namespace is created, an | ||
1042 | appropriate advertisement can be generated. The default keyword for | ||
1043 | the advertising of namespaces is "namespace". | ||
1044 | |||
1045 | |||
1046 | @node Anonymity level | ||
1047 | @subsubsection Anonymity level | ||
1048 | |||
1049 | The anonymity level determines how hard it should be for an adversary to | ||
1050 | determine the identity of the publisher or the searcher/downloader. An | ||
1051 | anonymity level of zero means that anonymity is not required. The default | ||
1052 | anonymity level of "1" means that anonymous routing is desired, but no | ||
1053 | particular amount of cover traffic is necessary. A powerful adversary | ||
1054 | might thus still be able to deduce the origin of the traffic using | ||
1055 | traffic analysis. Specifying higher anonymity levels increases the | ||
1056 | amount of cover traffic required. | ||
1057 | |||
1058 | The specific numeric value (for anonymity levels above 1) is simple: | ||
1059 | Given an anonymity level L (above 1), each request FS makes on your | ||
1060 | behalf must be hidden in L-1 equivalent requests of cover traffic | ||
1061 | (traffic your peer routes for others) in the same time-period. The | ||
1062 | time-period is twice the average delay by which GNUnet artificially | ||
1063 | delays traffic. | ||
1064 | |||
1065 | While higher anonymity levels may offer better privacy, they can also | ||
1066 | significantly hurt performance. | ||
1067 | |||
1068 | |||
1069 | @node Content Priority | ||
1070 | @subsubsection Content Priority | ||
1071 | |||
1072 | Depending on the peer's configuration, GNUnet peers migrate content | ||
1073 | between peers. Content in this sense are individual blocks of a file, | ||
1074 | not necessarily entire files. When peers run out of space (due to | ||
1075 | local publishing operations or due to migration of content from other | ||
1076 | peers), blocks sometimes need to be discarded. GNUnet first always | ||
1077 | discards expired blocks (typically, blocks are published with an | ||
1078 | expiration of about two years in the future; this is another option). | ||
1079 | If there is still not enough space, GNUnet discards the blocks with the | ||
1080 | lowest priority. The priority of a block is decided by its popularity | ||
1081 | (in terms of requests from peers we trust) and, in case of blocks | ||
1082 | published locally, the base-priority that was specified by the user | ||
1083 | when the block was published initially. | ||
1084 | |||
1085 | |||
1086 | @node Replication | ||
1087 | @subsubsection Replication | ||
1088 | |||
1089 | When peers migrate content to other systems, the replication level | ||
1090 | of a block is used to decide which blocks need to be migrated most | ||
1091 | urgently. GNUnet will always push the block with the highest | ||
1092 | replication level into the network, and then decrement the replication | ||
1093 | level by one. If all blocks reach replication level zero, the | ||
1094 | selection is simply random. | ||
1095 | |||
1096 | |||
1097 | @node Namespace Management | ||
1098 | @subsection Namespace Management | ||
1099 | |||
1100 | The @code{gnunet-identity} tool can be used to create egos. | ||
1101 | By default, @code{gnunet-identity --display} simply | ||
1102 | lists all locally available egos. | ||
1103 | |||
1104 | |||
1105 | @menu | ||
1106 | * Creating Egos:: | ||
1107 | * Deleting Egos:: | ||
1108 | @end menu | ||
1109 | |||
1110 | @node Creating Egos | ||
1111 | @subsubsection Creating Egos | ||
1112 | |||
1113 | With the @command{--create=NICK} option it can also be used to create a new | ||
1114 | ego. An ego is the virtual identity of the entity in control of a | ||
1115 | namespace or GNS zone. Anyone can create any number of egos. The | ||
1116 | provided NICK name automatically corresponds to a GNU Name System | ||
1117 | domain name. Thus, henceforth name resolution for any name ending in | ||
1118 | ``.NICK'' will use the NICK's zone. You should avoid using NICKs that | ||
1119 | collide with well-known DNS names. | ||
1120 | |||
1121 | Currently, the IDENTITY subsystem supports two types of identity keys: | ||
1122 | ECDSA and EdDSA. By default, ECDSA identities are creates with ECDSA keys. | ||
1123 | In order to create an identity with EdDSA keys, you can use the | ||
1124 | @command{--eddsa} flag. | ||
1125 | |||
1126 | @node Deleting Egos | ||
1127 | @subsubsection Deleting Egos | ||
1128 | |||
1129 | With the @command{-D NICK} option egos can be deleted. Once the ego | ||
1130 | has been deleted it is impossible to add content to the corresponding | ||
1131 | namespace or zone. However, the existing GNS zone data is currently | ||
1132 | not dropped. This may change in the future. | ||
1133 | |||
1134 | Deleting the pseudonym does not make the namespace or any content in | ||
1135 | it unavailable. | ||
1136 | |||
1137 | @node File-Sharing URIs | ||
1138 | @subsection File-Sharing URIs | ||
1139 | |||
1140 | |||
1141 | GNUnet (currently) uses four different types of URIs for | ||
1142 | file-sharing. They all begin with "gnunet://fs/". | ||
1143 | This section describes the four different URI types in detail. | ||
1144 | |||
1145 | For FS URIs empty KEYWORDs are not allowed. Quotes are allowed to | ||
1146 | denote whitespace between words. Keywords must contain a balanced | ||
1147 | number of double quotes. Doubles quotes can not be used in the actual | ||
1148 | keywords. This means that the string '""foo bar""' will be turned | ||
1149 | into two OR-ed keywords 'foo' and 'bar', not into '"foo bar"'. | ||
1150 | |||
1151 | @menu | ||
1152 | * Encoding of hash values in URIs:: | ||
1153 | * Content Hash Key (chk):: | ||
1154 | * Location identifiers (loc):: | ||
1155 | * Keyword queries (ksk):: | ||
1156 | * Namespace content (sks):: | ||
1157 | @end menu | ||
1158 | |||
1159 | @node Encoding of hash values in URIs | ||
1160 | @subsubsection Encoding of hash values in URIs | ||
1161 | |||
1162 | |||
1163 | Most URIs include some hash values. Hashes are encoded using | ||
1164 | base32hex (RFC 2938). | ||
1165 | |||
1166 | @cindex chk-uri | ||
1167 | @node Content Hash Key (chk) | ||
1168 | @subsubsection Content Hash Key (chk) | ||
1169 | |||
1170 | |||
1171 | A chk-URI is used to (uniquely) identify a file or directory | ||
1172 | and to allow peers to download the file. Files are stored in | ||
1173 | GNUnet as a tree of encrypted blocks. | ||
1174 | The chk-URI thus contains the information to download and decrypt | ||
1175 | those blocks. A chk-URI has the format | ||
1176 | "gnunet://fs/chk/KEYHASH.QUERYHASH.SIZE". Here, "SIZE" | ||
1177 | is the size of the file (which allows a peer to determine the | ||
1178 | shape of the tree), KEYHASH is the key used to decrypt the file | ||
1179 | (also the hash of the plaintext of the top block) and QUERYHASH | ||
1180 | is the query used to request the top-level block (also the hash | ||
1181 | of the encrypted block). | ||
1182 | |||
1183 | @cindex loc-uri | ||
1184 | @node Location identifiers (loc) | ||
1185 | @subsubsection Location identifiers (loc) | ||
1186 | |||
1187 | |||
1188 | For non-anonymous file-sharing, loc-URIs are used to specify which | ||
1189 | peer is offering the data (in addition to specifying all of the | ||
1190 | data from a chk-URI). Location identifiers include a digital | ||
1191 | signature of the peer to affirm that the peer is truly the | ||
1192 | origin of the data. The format is | ||
1193 | "gnunet://fs/loc/KEYHASH.QUERYHASH.SIZE.PEER.SIG.EXPTIME". | ||
1194 | Here, "PEER" is the public key of the peer (in GNUnet format in | ||
1195 | base32hex), SIG is the RSA signature (in GNUnet format in | ||
1196 | base32hex) and EXPTIME specifies when the signature expires | ||
1197 | (in milliseconds after 1970). | ||
1198 | |||
1199 | @cindex ksk-uri | ||
1200 | @node Keyword queries (ksk) | ||
1201 | @subsubsection Keyword queries (ksk) | ||
1202 | |||
1203 | |||
1204 | A keyword-URI is used to specify that the desired operation | ||
1205 | is the search using a particular keyword. The format is simply | ||
1206 | "gnunet://fs/ksk/KEYWORD". Non-ASCII characters can be specified | ||
1207 | using the typical URI-encoding (using hex values) from HTTP. | ||
1208 | "+" can be used to specify multiple keywords (which are then | ||
1209 | logically "OR"-ed in the search, results matching both keywords | ||
1210 | are given a higher rank): "gnunet://fs/ksk/KEYWORD1+KEYWORD2". | ||
1211 | ksk-URIs must not begin or end with the plus ('+') character. | ||
1212 | Furthermore they must not contain '++'. | ||
1213 | |||
1214 | @cindex sks-uri | ||
1215 | @node Namespace content (sks) | ||
1216 | @subsubsection Namespace content (sks) | ||
1217 | |||
1218 | |||
1219 | @b{Please note that the text in this subsection is outdated and needs} | ||
1220 | @b{to be rewritten for version 0.10!} | ||
1221 | @b{This especially concerns the terminology of Pseudonym/Ego/Identity.} | ||
1222 | |||
1223 | Namespaces are sets of files that have been approved by some (usually | ||
1224 | pseudonymous) user --- typically by that user publishing all of the | ||
1225 | files together. A file can be in many namespaces. A file is in a | ||
1226 | namespace if the owner of the ego (aka the namespace's private key) | ||
1227 | signs the CHK of the file cryptographically. An SKS-URI is used to | ||
1228 | search a namespace. The result is a block containing meta data, | ||
1229 | the CHK and the namespace owner's signature. The format of a sks-URI | ||
1230 | is "gnunet://fs/sks/NAMESPACE/IDENTIFIER". Here, "NAMESPACE" | ||
1231 | is the public key for the namespace. "IDENTIFIER" is a freely | ||
1232 | chosen keyword (or password!). A commonly used identifier is | ||
1233 | "root" which by convention refers to some kind of index or other | ||
1234 | entry point into the namespace. | ||
1235 | |||
1236 | @node GTK User Interface | ||
1237 | @subsection GTK User Interface | ||
1238 | This chapter describes first steps for file-sharing with GNUnet. | ||
1239 | To start, you should launch @command{gnunet-fs-gtk}. | ||
1240 | |||
1241 | As we want to be sure that the network contains the data that we are | ||
1242 | looking for for testing, we need to begin by publishing a file. | ||
1243 | |||
1244 | @menu | ||
1245 | * gtk-Publishing:: | ||
1246 | * gtk-Searching:: | ||
1247 | * gtk-Downloading:: | ||
1248 | @end menu | ||
1249 | |||
1250 | @node gtk-Publishing | ||
1251 | @subsubsection Publishing | ||
1252 | |||
1253 | |||
1254 | To publish a file, select "File Sharing" in the menu bar just below the | ||
1255 | "Statistics" icon, and then select "Publish" from the menu. | ||
1256 | |||
1257 | Afterwards, the following publishing dialog will appear: | ||
1258 | |||
1259 | @image{images/gnunet-gtk-0-10-fs-publish,5in,,The gnunet-fs-gtk publishing dialog} | ||
1260 | |||
1261 | In this dialog, select the "Add File" button. This will open a | ||
1262 | file selection dialog: | ||
1263 | |||
1264 | @image{images/gnunet-gtk-0-10-fs-publish-select,5in,,Dialog to select the file to publish (looks may differ for other Gtk+ versions)} | ||
1265 | |||
1266 | Now, you should select a file from your computer to be published on | ||
1267 | GNUnet. To see more of GNUnet's features later, you should pick a | ||
1268 | PNG or JPEG file this time. You can leave all of the other options | ||
1269 | in the dialog unchanged. Confirm your selection by pressing the "OK" | ||
1270 | button in the bottom right corner. Now, you will briefly see a | ||
1271 | "Messages..." dialog pop up, but most likely it will be too short for | ||
1272 | you to really read anything. That dialog is showing you progress | ||
1273 | information as GNUnet takes a first look at the selected file(s). | ||
1274 | For a normal image, this is virtually instant, but if you later | ||
1275 | import a larger directory you might be interested in the progress dialog | ||
1276 | and potential errors that might be encountered during processing. | ||
1277 | After the progress dialog automatically disappears, your file | ||
1278 | should now appear in the publishing dialog: | ||
1279 | |||
1280 | @image{images/gnunet-gtk-0-10-fs-publish-with-file,5in,,Publishing dialog with file added} | ||
1281 | |||
1282 | Now, select the file (by clicking on the file name) and then click | ||
1283 | the "Edit" button. This will open the editing dialog: | ||
1284 | |||
1285 | @image{images/gnunet-gtk-0-10-fs-publish-editing,5in,,Editing meta data of a file to be published} | ||
1286 | |||
1287 | In this dialog, you can see many details about your file. In the | ||
1288 | top left area, you can see meta data extracted about the file, | ||
1289 | such as the original filename, the mimetype and the size of the image. | ||
1290 | In the top right, you should see a preview for the image | ||
1291 | (if GNU libextractor was installed correctly with the | ||
1292 | respective plugins). Note that if you do not see a preview, this | ||
1293 | is not a disaster, but you might still want to install more of | ||
1294 | GNU libextractor in the future. In the bottom left, the dialog contains | ||
1295 | a list of keywords. These are the keywords under which the file will be | ||
1296 | made available. The initial list will be based on the extracted meta data. | ||
1297 | Additional publishing options are in the right bottom corner. We will | ||
1298 | now add an additional keyword to the list of keywords. This is done by | ||
1299 | entering the keyword above the keyword list between the label "Keyword" | ||
1300 | and the "Add keyword" button. Enter "test" and select "Add keyword". | ||
1301 | Note that the keyword will appear at the bottom of the existing keyword | ||
1302 | list, so you might have to scroll down to see it. Afterwards, push the | ||
1303 | "OK" button at the bottom right of the dialog. | ||
1304 | |||
1305 | You should now be back at the "Publish content on GNUnet" dialog. Select | ||
1306 | "Execute" in the bottom right to close the dialog and publish your file | ||
1307 | on GNUnet! Afterwards, you should see the main dialog with a new area | ||
1308 | showing the list of published files (or ongoing publishing operations | ||
1309 | with progress indicators). | ||
1310 | |||
1311 | @node gtk-Searching | ||
1312 | @subsubsection Searching | ||
1313 | |||
1314 | |||
1315 | Below the menu bar, there are four entry widges labeled "Namespace", | ||
1316 | "Keywords", "Anonymity" and "Mime-type" (from left to right). These | ||
1317 | widgets are used to control searching for files in GNUnet. Between the | ||
1318 | "Keywords" and "Anonymity" widgets, there is also a big "Search" button, | ||
1319 | which is used to initiate the search. We will ignore the "Namespace", | ||
1320 | "Anonymity" and "Mime-type" options in this tutorial, please leave them | ||
1321 | empty. Instead, simply enter "test" under "Keywords" and press "Search". | ||
1322 | Afterwards, you should immediately see a new tab labeled after your | ||
1323 | search term, followed by the (current) number of search | ||
1324 | results --- "(15)" in our screenshot. Note that your results may | ||
1325 | vary depending on what other users may have shared and how your | ||
1326 | peer is connected. | ||
1327 | |||
1328 | You can now select one of the search results. Once you do this, | ||
1329 | additional information about the result should be displayed on the | ||
1330 | right. If available, a preview image should appear on the top right. | ||
1331 | Meta data describing the file will be listed at the bottom right. | ||
1332 | |||
1333 | Once a file is selected, at the bottom of the search result list | ||
1334 | a little area for downloading appears. | ||
1335 | |||
1336 | @node gtk-Downloading | ||
1337 | @subsubsection Downloading | ||
1338 | |||
1339 | |||
1340 | In the downloading area, you can select the target directory (default is | ||
1341 | "Downloads") and specify the desired filename (by default the filename it | ||
1342 | taken from the meta data of the published file). Additionally, you can | ||
1343 | specify if the download should be anonymous and (for directories) if | ||
1344 | the download should be recursive. In most cases, you can simply start | ||
1345 | the download with the "Download!" button. | ||
1346 | |||
1347 | Once you selected download, the progress of the download will be | ||
1348 | displayed with the search result. You may need to resize the result | ||
1349 | list or scroll to the right. The "Status" column shows the current | ||
1350 | status of the download, and "Progress" how much has been completed. | ||
1351 | When you close the search tab (by clicking on the "X" button next to | ||
1352 | the "test" label), ongoing and completed downloads are not aborted | ||
1353 | but moved to a special "*" tab. | ||
1354 | |||
1355 | You can remove completed downloads from the "*" tab by clicking the | ||
1356 | cleanup button next to the "*". You can also abort downloads by right | ||
1357 | clicking on the respective download and selecting "Abort download" | ||
1358 | from the menu. | ||
1359 | |||
1360 | That's it, you now know the basics for file-sharing with GNUnet! | ||
1361 | |||
1362 | |||
1363 | @node The GNU Name System | ||
1364 | @section The GNU Name System | ||
1365 | |||
1366 | |||
1367 | |||
1368 | The GNU Name System (GNS) is secure and decentralized naming system. | ||
1369 | It allows its users to register names as @dfn{top-level domains} (TLDs) and | ||
1370 | resolve other namespaces within their TLDs. | ||
1371 | |||
1372 | GNS is designed to provide: | ||
1373 | @itemize @bullet | ||
1374 | @item Censorship resistance | ||
1375 | @item Query privacy | ||
1376 | @item Secure name resolution | ||
1377 | @item Compatibility with DNS | ||
1378 | @end itemize | ||
1379 | |||
1380 | For the initial configuration and population of your | ||
1381 | GNS installation, please follow the GNS setup instructions. | ||
1382 | The remainder of this chapter will provide some background on GNS | ||
1383 | and then describe how to use GNS in more detail. | ||
1384 | |||
1385 | Unlike DNS, GNS does not rely on central root zones or authorities. | ||
1386 | Instead any user administers their own root and can can create arbitrary | ||
1387 | name value mappings. Furthermore users can delegate resolution to other | ||
1388 | users' zones just like DNS NS records do. Zones are uniquely identified | ||
1389 | via public keys and resource records are signed using the corresponding | ||
1390 | public key. Delegation to another user's zone is done using special PKEY | ||
1391 | records and petnames. A petname is a name that can be freely chosen by | ||
1392 | the user. This results in non-unique name-value mappings as | ||
1393 | @code{@uref{http://www.bob.gnu/, www.bob.gnu}} to one user might be | ||
1394 | @code{@uref{http://www.friend.gnu/, www.friend.gnu}} for someone else. | ||
1395 | |||
1396 | |||
1397 | @menu | ||
1398 | * Creating a Zone:: | ||
1399 | * Maintaining your own Zones:: | ||
1400 | * Obtaining your Zone Key:: | ||
1401 | * Adding Links to Other Zones:: | ||
1402 | * Using Public Keys as Top Level Domains:: | ||
1403 | * Resource Records in GNS:: | ||
1404 | * Synchronizing with legacy DNS:: | ||
1405 | * Migrating an existing DNS zone into GNS:: | ||
1406 | @end menu | ||
1407 | |||
1408 | |||
1409 | @node Creating a Zone | ||
1410 | @subsection Creating a Zone | ||
1411 | |||
1412 | To use GNS, you probably should create at least one zone of your own. | ||
1413 | You can create any number of zones using the gnunet-identity tool | ||
1414 | using: | ||
1415 | |||
1416 | @example | ||
1417 | $ gnunet-identity --create="myzone" | ||
1418 | @end example | ||
1419 | |||
1420 | Henceforth, on your system you control the TLD ``myzone''. | ||
1421 | |||
1422 | All of your zones can be listed (displayed) using the | ||
1423 | @command{gnunet-identity} command line tool as well: | ||
1424 | |||
1425 | @example | ||
1426 | $ gnunet-identity --display | ||
1427 | @end example | ||
1428 | |||
1429 | @node Maintaining your own Zones | ||
1430 | @subsection Maintaining your own Zones | ||
1431 | |||
1432 | @noindent | ||
1433 | Now you can add (or edit, or remove) records in your GNS zone using the | ||
1434 | @command{gnunet-namestore-gtk} GUI or using the @command{gnunet-namestore} | ||
1435 | command-line tool. | ||
1436 | In either case, your records will be stored in an SQL database under | ||
1437 | control of the @command{gnunet-service-namestore}. | ||
1438 | Note that if multiple users use one peer, the namestore database will | ||
1439 | include the combined records of all users. | ||
1440 | However, users will not be able to see each other's records | ||
1441 | if they are marked as private. | ||
1442 | |||
1443 | To provide a short example for editing your own zone, suppose you | ||
1444 | have your own web server with the IP @code{1.2.3.4}. Then you can put an | ||
1445 | @code{A} record (@code{A} records in DNS are for IPv4 IP addresses) | ||
1446 | into your local zone ``myzone'' using the command: | ||
1447 | |||
1448 | @example | ||
1449 | $ gnunet-namestore -z myzone -a -n www -t A -V 1.2.3.4 -e never | ||
1450 | @end example | ||
1451 | |||
1452 | @noindent | ||
1453 | Afterwards, you will be able to access your webpage under "www.myzone" | ||
1454 | (assuming your webserver does not use virtual hosting, if it does, | ||
1455 | please read up on setting up the GNS proxy). | ||
1456 | |||
1457 | Similar commands will work for other types of DNS and GNS records, | ||
1458 | the syntax largely depending on the type of the record. | ||
1459 | Naturally, most users may find editing the zones using the | ||
1460 | @command{gnunet-namestore-gtk} GUI to be easier. | ||
1461 | |||
1462 | @node Obtaining your Zone Key | ||
1463 | @subsection Obtaining your Zone Key | ||
1464 | |||
1465 | Each zone in GNS has a public-private key. Usually, gnunet-namestore and | ||
1466 | gnunet-setup will access your private key as necessary, so you do not | ||
1467 | have to worry about those. What is important is your public key | ||
1468 | (or rather, the hash of your public key), as you will likely want to | ||
1469 | give it to others so that they can securely link to you. | ||
1470 | |||
1471 | You can usually get the hash of your public key using | ||
1472 | |||
1473 | @example | ||
1474 | $ gnunet-identity -d $options | grep myzone | awk '@{print $3@}' | ||
1475 | @end example | ||
1476 | |||
1477 | @noindent | ||
1478 | For example, the output might be something like: | ||
1479 | |||
1480 | @example | ||
1481 | DC3SEECJORPHQNVRH965A6N74B1M37S721IG4RBQ15PJLLPJKUE0 | ||
1482 | @end example | ||
1483 | |||
1484 | @noindent | ||
1485 | Alternatively, you can obtain a QR code with your zone key AND your | ||
1486 | pseudonym from gnunet-namestore-gtk. The QR code is displayed in the | ||
1487 | main window and can be stored to disk using the ``Save as'' button | ||
1488 | next to the image. | ||
1489 | |||
1490 | @node Adding Links to Other Zones | ||
1491 | @subsection Adding Links to Other Zones | ||
1492 | |||
1493 | |||
1494 | A central operation in GNS is the ability to securely delegate to | ||
1495 | other zones. Basically, by adding a delegation you make all of the | ||
1496 | names from the other zone available to yourself. This section | ||
1497 | describes how to create delegations. | ||
1498 | |||
1499 | Suppose you have a friend who you call 'bob' who also uses GNS. | ||
1500 | You can then delegate resolution of names to Bob's zone by adding | ||
1501 | a PKEY record to their local zone: | ||
1502 | |||
1503 | @example | ||
1504 | $ gnunet-namestore -a -n bob --type PKEY -V XXXX -e never -Z myzone | ||
1505 | @end example | ||
1506 | |||
1507 | @noindent | ||
1508 | Note that ``XXXX'' in the command above must be replaced with the hash | ||
1509 | of Bob's public key (the output your friend obtained using the | ||
1510 | @command{gnunet-identity} command from the previous section and told | ||
1511 | you, for example by giving you a business card containing this | ||
1512 | information as a QR code). | ||
1513 | |||
1514 | Assuming Bob has an ``A'' record for their website under the name of | ||
1515 | ``www'' in his zone, you can then access Bob's website under | ||
1516 | ``www.bob.myzone'' --- as well as any (public) GNS record that Bob has | ||
1517 | in their zone by replacing www with the respective name of the | ||
1518 | record in Bob's zone. | ||
1519 | |||
1520 | @c themselves? themself? | ||
1521 | Furthermore, if Bob has themselves a (public) delegation to Carol's | ||
1522 | zone under "carol", you can access Carol's records under | ||
1523 | ``NAME.carol.bob.myzone'' (where ``NAME'' is the name of Carol's | ||
1524 | record you want to access). | ||
1525 | |||
1526 | |||
1527 | @node Using Public Keys as Top Level Domains | ||
1528 | @subsection Using Public Keys as Top Level Domains | ||
1529 | |||
1530 | |||
1531 | GNS also assumes responsibility for any name that uses in a | ||
1532 | well-formed public key for the TLD. Names ending this way are then | ||
1533 | resolved by querying the respective zone. Such public key TLDs are | ||
1534 | expected to be used under rare circumstances where globally unique | ||
1535 | names are required, and for integration with legacy systems. | ||
1536 | |||
1537 | @node Resource Records in GNS | ||
1538 | @subsection Resource Records in GNS | ||
1539 | |||
1540 | |||
1541 | GNS supports the majority of the DNS records as defined in | ||
1542 | @uref{http://www.ietf.org/rfc/rfc1035.txt, RFC 1035}. Additionally, | ||
1543 | GNS defines some new record types the are unique to the GNS system. | ||
1544 | For example, GNS-specific resource records are used to give petnames | ||
1545 | for zone delegation, revoke zone keys and provide some compatibility | ||
1546 | features. | ||
1547 | |||
1548 | For some DNS records, GNS does extended processing to increase their | ||
1549 | usefulness in GNS. In particular, GNS introduces special names | ||
1550 | referred to as "zone relative names". Zone relative names are allowed | ||
1551 | in some resource record types (for example, in NS and CNAME records) | ||
1552 | and can also be used in links on webpages. Zone relative names end | ||
1553 | in ".+" which indicates that the name needs to be resolved relative | ||
1554 | to the current authoritative zone. The extended processing of those | ||
1555 | names will expand the ".+" with the correct delegation chain to the | ||
1556 | authoritative zone (replacing ".+" with the name of the location | ||
1557 | where the name was encountered) and hence generate a | ||
1558 | valid GNS name. | ||
1559 | |||
1560 | The GNS currently supports the record types as defined in | ||
1561 | @uref{https://git.gnunet.org/gana.git/tree/gnu-name-system-record-types/registry.rec, GANA}. | ||
1562 | In addition, GNS supports DNS record types, such as A, AAAA or TXT. | ||
1563 | |||
1564 | For a complete description of the records, please refer to the specification | ||
1565 | at @uref{https://lsd.gnunet.org/lsd0001, LSD0001}. | ||
1566 | |||
1567 | In the following, we discuss GNS records with specific behaviour or special | ||
1568 | handling of DNS records. | ||
1569 | |||
1570 | @menu | ||
1571 | * NICK:: | ||
1572 | * PKEY:: | ||
1573 | * BOX:: | ||
1574 | * LEHO:: | ||
1575 | * VPN:: | ||
1576 | * REDIRECT:: | ||
1577 | * GNS2DNS:: | ||
1578 | * TOMBSTONE:: | ||
1579 | * SOA SRV PTR and MX:: | ||
1580 | @end menu | ||
1581 | |||
1582 | @node NICK | ||
1583 | @subsubsection NICK | ||
1584 | |||
1585 | A NICK record is used to give a zone a name. With a NICK record, you | ||
1586 | can essentially specify how you would like to be called. GNS expects | ||
1587 | this record under the empty label ``@@'' in the zone's database | ||
1588 | (NAMESTORE); however, it will then automatically be copied into each | ||
1589 | record set, so that clients never need to do a separate lookup to | ||
1590 | discover the NICK record. Also, users do not usually have to worry | ||
1591 | about setting the NICK record: it is automatically set to the local | ||
1592 | name of the TLD. | ||
1593 | |||
1594 | @b{Example}@ | ||
1595 | |||
1596 | @example | ||
1597 | Name: @@; RRType: NICK; Value: bob | ||
1598 | @end example | ||
1599 | |||
1600 | @noindent | ||
1601 | This record in Bob's zone will tell other users that this zone wants | ||
1602 | to be referred to as 'bob'. Note that nobody is obliged to call Bob's | ||
1603 | zone 'bob' in their own zones. It can be seen as a | ||
1604 | recommendation ("Please call this zone 'bob'"). | ||
1605 | |||
1606 | @node PKEY | ||
1607 | @subsubsection PKEY | ||
1608 | |||
1609 | PKEY records are used to add delegation to other users' zones and | ||
1610 | give those zones a petname. | ||
1611 | |||
1612 | @b{Example}@ | ||
1613 | |||
1614 | Let Bob's zone be identified by the hash "ABC012". Bob is your friend | ||
1615 | so you want to give them the petname "friend". Then you add the | ||
1616 | following record to your zone: | ||
1617 | |||
1618 | @example | ||
1619 | Name: friend; RRType: PKEY; Value: ABC012; | ||
1620 | @end example | ||
1621 | |||
1622 | @noindent | ||
1623 | This will allow you to resolve records in bob's zone | ||
1624 | under "*.friend.gnu". | ||
1625 | |||
1626 | @node BOX | ||
1627 | @subsubsection BOX | ||
1628 | |||
1629 | BOX records are there to integrate information from TLSA or | ||
1630 | SRV records under the main label. In DNS, TLSA and SRV records | ||
1631 | use special names of the form @code{_port._proto.(label.)*tld} to | ||
1632 | indicate the port number and protocol (like TCP or UDP) for which | ||
1633 | the TLSA or SRV record is valid. This causes various problems, and | ||
1634 | is elegantly solved in GNS by integrating the protocol and port | ||
1635 | numbers together with the respective value into a "BOX" record. | ||
1636 | Note that in the GUI, you do not get to edit BOX records directly | ||
1637 | right now --- the GUI will provide the illusion of directly | ||
1638 | editing the TLSA and SRV records, even though they internally | ||
1639 | are BOXed up. | ||
1640 | |||
1641 | @node LEHO | ||
1642 | @subsubsection LEHO | ||
1643 | |||
1644 | The LEgacy HOstname of a server. Some webservers expect a specific | ||
1645 | hostname to provide a service (virtual hosting). Also SSL | ||
1646 | certificates usually contain DNS names. To provide the expected | ||
1647 | legacy DNS name for a server, the LEHO record can be used. | ||
1648 | To mitigate the just mentioned issues the GNS proxy has to be used. | ||
1649 | The GNS proxy will use the LEHO information to apply the necessary | ||
1650 | transformations. | ||
1651 | |||
1652 | @node VPN | ||
1653 | @subsubsection VPN | ||
1654 | |||
1655 | GNS allows easy access to services provided by the GNUnet Virtual Public | ||
1656 | Network. When the GNS resolver encounters a VPN record it will contact | ||
1657 | the VPN service to try and allocate an IPv4/v6 address (if the queries | ||
1658 | record type is an IP address) that can be used to contact the service. | ||
1659 | |||
1660 | @b{Example}@ | ||
1661 | |||
1662 | I want to provide access to the VPN service "web.gnu." on port 80 on peer | ||
1663 | ABC012:@ | ||
1664 | Name: www; RRType: VPN; Value: 80 ABC012 web.gnu. | ||
1665 | |||
1666 | The peer ABC012 is configured to provide an exit point for the service | ||
1667 | "web.gnu." on port 80 to it's server running locally on port 8080 by | ||
1668 | having the following lines in the @file{gnunet.conf} configuration file: | ||
1669 | |||
1670 | @example | ||
1671 | [web.gnunet.] | ||
1672 | TCP_REDIRECTS = 80:localhost4:8080 | ||
1673 | @end example | ||
1674 | |||
1675 | @node REDIRECT | ||
1676 | @subsubsection REDIRECT | ||
1677 | |||
1678 | As specified in LSD0001 whenever a REDIRECT is encountered the query | ||
1679 | needs to be restarted with the specified name. A REDIRECT | ||
1680 | can either be: | ||
1681 | |||
1682 | @itemize @bullet | ||
1683 | @item A zone relative name, | ||
1684 | @item A zkey name or | ||
1685 | @item A DNS name (in which case resolution will continue outside | ||
1686 | of GNS with the systems DNS resolver) | ||
1687 | @end itemize | ||
1688 | |||
1689 | @node GNS2DNS | ||
1690 | @subsubsection GNS2DNS | ||
1691 | |||
1692 | GNS can delegate authority to a legacy DNS zone. For this, the | ||
1693 | name of the DNS nameserver and the name of the DNS zone are | ||
1694 | specified in a GNS2DNS record. | ||
1695 | |||
1696 | @b{Example} | ||
1697 | |||
1698 | @example | ||
1699 | Name: pet; RRType: GNS2DNS; Value: gnunet.org@@a.ns.joker.com | ||
1700 | @end example | ||
1701 | |||
1702 | @noindent | ||
1703 | Any query to @code{pet.gnu} will then be delegated to the DNS server at | ||
1704 | @code{a.ns.joker.com}. For example, | ||
1705 | @code{@uref{http://www.pet.gnu/, www.pet.gnu}} will result in a DNS query | ||
1706 | for @code{@uref{http://www.gnunet.org/, www.gnunet.org}} to the server | ||
1707 | at @code{a.ns.joker.com}. Delegation to DNS via NS records in GNS can | ||
1708 | be useful if you do not want to start resolution in the DNS root zone | ||
1709 | (due to issues such as censorship or availability). | ||
1710 | |||
1711 | Note that you would typically want to use a relative name for the | ||
1712 | nameserver, like so: | ||
1713 | |||
1714 | @example | ||
1715 | Name: pet; RRType: GNS2DNS; Value: gnunet.org@@ns-joker.+@ | ||
1716 | |||
1717 | Name: ns-joker; RRType: A; Value: 184.172.157.218 | ||
1718 | @end example | ||
1719 | |||
1720 | @noindent | ||
1721 | This way, you can avoid involving the DNS hierarchy in the resolution of | ||
1722 | @code{a.ns.joker.com}. In the example above, the problem may not be | ||
1723 | obvious as the nameserver for "gnunet.org" is in the ".com" zone. | ||
1724 | However, imagine the nameserver was "ns.gnunet.org". In this case, | ||
1725 | delegating to "ns.gnunet.org" would mean that despite using GNS, | ||
1726 | censorship in the DNS ".org" zone would still be effective. | ||
1727 | |||
1728 | @node TOMBSTONE | ||
1729 | @subsubsection TOMBSTONE | ||
1730 | |||
1731 | The GNUnet GNS implementation uses the TOMBSTONE record to ensure | ||
1732 | ciphertext indistinguishability for published records. | ||
1733 | It must be ensured that when relative expiration times are decreased, the | ||
1734 | expiration time of the next record block MUST be after the last published block. | ||
1735 | A similar issue arises if the record set under a label is deleted and reused | ||
1736 | later. | ||
1737 | |||
1738 | The creation and maintenance of the TOMBSTONE record is done automatically. | ||
1739 | You do not need to mind it yourself and can safely ignore any TOMBSTONE | ||
1740 | blocks you may see when investigating your zone(s). | ||
1741 | TOMBSTONE records are always private and will never be published. | ||
1742 | |||
1743 | @node SOA SRV PTR and MX | ||
1744 | @subsubsection SOA SRV PTR and MX | ||
1745 | |||
1746 | The domain names in those records can, again, be either | ||
1747 | |||
1748 | @itemize @bullet | ||
1749 | @item A zone relative name, | ||
1750 | @item A zkey name or | ||
1751 | @item A DNS name | ||
1752 | @end itemize | ||
1753 | |||
1754 | The resolver will expand the zone relative name if possible. | ||
1755 | Note that when using MX records within GNS, the target mail | ||
1756 | server might still refuse to accept e-mails to the resulting | ||
1757 | domain as the name might not match. GNS-enabled mail clients | ||
1758 | should use the ZKEY zone as the destination hostname and | ||
1759 | GNS-enabled mail servers should be configured to accept | ||
1760 | e-mails to the ZKEY-zones of all local users. | ||
1761 | |||
1762 | To add a SOA record via the gnunet-namestore command line | ||
1763 | tool use the following syntax for the value option. Choose | ||
1764 | the other options according to your preference, however in | ||
1765 | this example we will use a relative expiry, add the record | ||
1766 | under the label @ and add the records to the zone bar | ||
1767 | which already exists: | ||
1768 | |||
1769 | @example | ||
1770 | $ gnunet-namestore -a -n @ -t SOA -z bar -e 3600s -V \ | ||
1771 | > "rname=$PRIMARY_NS \ | ||
1772 | > mname=$CONTACT_MAIL \ | ||
1773 | > $SERIAL,$REFRESH,$RETRY,$EXPIRY,$MINIMUM_TTL" | ||
1774 | @end example | ||
1775 | |||
1776 | The above command filled in with values looks like this: | ||
1777 | @example | ||
1778 | $ gnunet-namestore -a -n @ -t SOA -z bar -e 3600s -V \ | ||
1779 | > "rname=ns1.bar \ | ||
1780 | > mname=root.bar \ | ||
1781 | > 2019081701,3600,1800,86400,7200" | ||
1782 | @end example | ||
1783 | |||
1784 | MX records use a similar syntax which is outlined in the | ||
1785 | example below. $SERVER is a domain name as mentioned above. | ||
1786 | @example | ||
1787 | $ gnunet-namestore -a -n mail -t MX -z bar -e 3600s -V \ | ||
1788 | > "$PRIORITY,$SERVER" | ||
1789 | @end example | ||
1790 | |||
1791 | With the values substituted this is an example of a working | ||
1792 | command: | ||
1793 | @example | ||
1794 | $ gnunet-namestore -a -n mail -t MX -z bar -e 3600s -V \ | ||
1795 | > "10,mail.bar" | ||
1796 | @end example | ||
1797 | |||
1798 | @node Synchronizing with legacy DNS | ||
1799 | @subsection Synchronizing with legacy DNS | ||
1800 | |||
1801 | If you want to support GNS but the master database for a zone | ||
1802 | is only available and maintained in DNS, GNUnet includes the | ||
1803 | @command{gnunet-zoneimport} tool to monitor a DNS zone and | ||
1804 | automatically import records into GNS. Today, the tool does | ||
1805 | not yet support DNS AF(X)R, as we initially used it on the | ||
1806 | ``.fr'' zone which does not allow us to perform a DNS zone | ||
1807 | transfer. Instead, @command{gnunet-zoneimport} reads a list | ||
1808 | of DNS domain names from @code{stdin}, issues DNS queries for | ||
1809 | each, converts the obtained records (if possible) and stores | ||
1810 | the result in the namestore. | ||
1811 | |||
1812 | @image{images/gns,6in,, picture of DNS-GNS data flow} | ||
1813 | |||
1814 | The zonemaster service then takes the records from the namestore, | ||
1815 | publishes them into the DHT which makes the result available to the | ||
1816 | GNS resolver. In the GNS configuration, non-local zones can be | ||
1817 | configured to be intercepted by specifying ``.tld = PUBLICKEY'' in the | ||
1818 | configuration file in the ``[gns]'' section. | ||
1819 | |||
1820 | Note that the namestore by default also populates the namecache. | ||
1821 | This pre-population is cryptographically expensive. Thus, on | ||
1822 | systems that only serve to import a large (millions of records) | ||
1823 | DNS zone and that do not have a local gns service in use, it | ||
1824 | is thus advisable to disable the namecache by setting the | ||
1825 | option ``DISABLE'' to ``YES'' in section ``[namecache]''. | ||
1826 | |||
1827 | @node Migrating an existing DNS zone into GNS | ||
1828 | @subsection Migrating an existing DNS zone into GNS | ||
1829 | |||
1830 | Ascension is a tool to migrate existing DNS zones into GNS. | ||
1831 | |||
1832 | @xref{Migrating existing DNS zones into GNS}, for installation instructions and | ||
1833 | further information about Ascension. | ||
1834 | |||
1835 | Compared to the gnunet-zoneimport tool it strictly uses AXFR or IXFR depending | ||
1836 | on whether or not there exists a SOA record for the zone. If that is the case it | ||
1837 | will take the serial as a reference point and request the zone. The server will | ||
1838 | either answer the IXFR request with a correct incremental zone or with the | ||
1839 | entire zone, which depends on the server configuration. | ||
1840 | |||
1841 | After installing the tool according to the README file you have the following | ||
1842 | options: | ||
1843 | |||
1844 | @example | ||
1845 | Ascension | ||
1846 | Usage: | ||
1847 | ascension <domain> [-d] [-p] [-s] [--minimum-ttl=<ttl>] \ | ||
1848 | [--dry-run] | ||
1849 | ascension <domain> <port> [-d] [-p] [-s] \ | ||
1850 | [--minimum-ttl=<ttl>] [--dry-run] | ||
1851 | ascension <domain> -n <transferns> [-d] [-p] \ | ||
1852 | [-s] [--minimum-ttl=<ttl>] [--dry-run] | ||
1853 | ascension <domain> -n <transferns> <port> [-d] \ | ||
1854 | [-p] [-s] [--minimum-ttl=<ttl>] [--dry-run] | ||
1855 | ascension -p | --public | ||
1856 | ascension -d | --debug | ||
1857 | ascension -s | --standalone | ||
1858 | ascension -h | --help | ||
1859 | ascension -v | --version | ||
1860 | |||
1861 | Options: | ||
1862 | <domain> Domain to migrate | ||
1863 | <port> Port for zone transfer | ||
1864 | <transferns> DNS Server that does the zone transfer | ||
1865 | --minimum-ttl=<ttl> Minimum TTL for records to migrate \ | ||
1866 | [default: 3600] | ||
1867 | --dry-run Only try if a zone transfer is allowed | ||
1868 | -p --public Make records public on the DHT | ||
1869 | -s --standalone Run ascension once | ||
1870 | -d --debug Enable debugging | ||
1871 | -h --help Show this screen. | ||
1872 | -v --version Show version. | ||
1873 | @end example | ||
1874 | |||
1875 | Before you can migrate any zone though, you need to start a local GNUnet peer: | ||
1876 | @example | ||
1877 | $ gnunet-arm -s | ||
1878 | @end example | ||
1879 | |||
1880 | To migrate the Syrian top level domain - one of the few top level domains that | ||
1881 | support zone transfers - into GNS use the following command: | ||
1882 | |||
1883 | @example | ||
1884 | $ ascension sy. -n ns1.tld.sy. -p | ||
1885 | @end example | ||
1886 | |||
1887 | The -p flag will tell GNS to put these records on the DHT so that other users | ||
1888 | may resolve these records by using the public key of the zone. | ||
1889 | |||
1890 | Once the zone is migrated, Ascension will output a message telling you, that it | ||
1891 | will refresh the zone after the time has elapsed. You can resolve the names in | ||
1892 | the zone directly using GNS or if you want to use it with your browser, check | ||
1893 | out the GNS manual section. @ref{Configuring the GNU Name System}. To resolve | ||
1894 | the records from another system you need the respective zones PKEY. To get the | ||
1895 | zones public key, you can run the following command: | ||
1896 | |||
1897 | @example | ||
1898 | $ gnunet-identity -dqe sy | ||
1899 | @end example | ||
1900 | |||
1901 | Where "sy" is the name of the zone you want to migrate. | ||
1902 | |||
1903 | You can share the PKEY of the zone with your friends. They can then resolve | ||
1904 | records in the zone by doing a lookup replacing the zone label with your PKEY: | ||
1905 | |||
1906 | @example | ||
1907 | $ gnunet-gns -t SOA -u "$PKEY" | ||
1908 | @end example | ||
1909 | |||
1910 | The program will continue to run as a daemon and update once the refresh time | ||
1911 | specified in the zones SOA record has elapsed. | ||
1912 | |||
1913 | DNSCurve style records are supported in the latest release and they are added | ||
1914 | as a PKEY record to be referred to the respective GNS public key. Key | ||
1915 | distribution is still a problem but provided someone else has a public key | ||
1916 | under a given label it can be looked up. | ||
1917 | |||
1918 | There is an unofficial Debian package called python3-ascension that adds a | ||
1919 | system user ascension and runs a GNUnet peer in the background. | ||
1920 | |||
1921 | Ascension-bind is also an unofficial Debian package that on installation checks | ||
1922 | for running DNS zones and whether or not they are transferable using DNS zone | ||
1923 | transfer (AXFR). It asks the administrator which zones to migrate into GNS and | ||
1924 | installs a systemd unit file to keep the zone up to date. If you want to | ||
1925 | migrate different zones you might want to check the unit file from the package | ||
1926 | as a guide. | ||
1927 | |||
1928 | @node reclaimID Identity Provider | ||
1929 | @section reclaimID Identity Provider | ||
1930 | |||
1931 | The re:claimID Identity Provider (IdP) is a decentralized IdP service. | ||
1932 | It allows its users to manage and authorize third parties to access | ||
1933 | their identity attributes such as email or shipping addresses. | ||
1934 | |||
1935 | It basically mimics the concepts of centralized IdPs, such as those | ||
1936 | offered by Google or Facebook. | ||
1937 | Like other IdPs, reclaimID features an (optional) OpenID Connect | ||
1938 | 1.0-compliant protocol layer that can be used for websites to | ||
1939 | integrate reclaimID as an Identity Provider with little effort. | ||
1940 | |||
1941 | @menu | ||
1942 | * Managing Attributes:: | ||
1943 | * Managing Credentials:: | ||
1944 | * Sharing Attributes with Third Parties:: | ||
1945 | * Revoking Authorizations of Third Parties:: | ||
1946 | * OpenID Connect:: | ||
1947 | * Providing Third Party Attestation:: | ||
1948 | @end menu | ||
1949 | |||
1950 | @node Managing Attributes | ||
1951 | @subsection Managing Attributes | ||
1952 | |||
1953 | Before adding attributes to an identity, you must first create an ego: | ||
1954 | |||
1955 | @example | ||
1956 | $ gnunet-identity --create="user" | ||
1957 | @end example | ||
1958 | |||
1959 | Henceforth, you can manage a new user profile of the user ``user''. | ||
1960 | |||
1961 | To add an email address to your user profile, simply use the @command{gnunet-reclaim} command line tool:: | ||
1962 | |||
1963 | @example | ||
1964 | $ gnunet-reclaim -e "user" -a "email" -V "username@@example.gnunet" | ||
1965 | @end example | ||
1966 | |||
1967 | All of your attributes can be listed using the @command{gnunet-reclaim} | ||
1968 | command line tool as well: | ||
1969 | |||
1970 | @example | ||
1971 | $ gnunet-reclaim -e "user" -D | ||
1972 | @end example | ||
1973 | |||
1974 | Currently, and by default, attribute values are interpreted as plain text. | ||
1975 | In the future there might be more value types such as X.509 certificate credentials. | ||
1976 | |||
1977 | @node Managing Credentials | ||
1978 | @subsection Managing Credentials | ||
1979 | |||
1980 | Attribute values may reference a claim in a third party attested credential. | ||
1981 | Such a credential can have a variety of formats such as JSON-Web-Tokens or | ||
1982 | X.509 certificates. | ||
1983 | Currently, reclaimID only supports JSON-Web-Token credentials. | ||
1984 | |||
1985 | To add a credential to your user profile, invoke the @command{gnunet-reclaim} command line tool as follows: | ||
1986 | |||
1987 | @example | ||
1988 | $ gnunet-reclaim -e "user"\ | ||
1989 | --credential-name="email"\ | ||
1990 | --credential-type="JWT"\ | ||
1991 | --value="ey..." | ||
1992 | @end example | ||
1993 | |||
1994 | All of your credentials can be listed using the @command{gnunet-reclaim} | ||
1995 | command line tool as well: | ||
1996 | |||
1997 | @example | ||
1998 | $ gnunet-reclaim -e "user" --credentials | ||
1999 | @end example | ||
2000 | |||
2001 | In order to add an attribe backed by a credential, specify the attribute | ||
2002 | value as the claim name in the credential to reference along with the credential | ||
2003 | ID: | ||
2004 | |||
2005 | @example | ||
2006 | $ gnunet-reclaim -e "user"\ | ||
2007 | --add="email"\ | ||
2008 | --value="verified_email"\ | ||
2009 | --credential-id="<CREDENTIAL_ID>" | ||
2010 | @end example | ||
2011 | |||
2012 | |||
2013 | @node Sharing Attributes with Third Parties | ||
2014 | @subsection Sharing Attributes with Third Parties | ||
2015 | |||
2016 | If you want to allow a third party such as a website or friend to access to your attributes (or a subset thereof) execute: | ||
2017 | |||
2018 | @example | ||
2019 | $ TICKET=$(gnunet-reclaim -e "user"\ | ||
2020 | -r "$RP_KEY"\ | ||
2021 | -i "attribute1,attribute2,...") | ||
2022 | @end example | ||
2023 | |||
2024 | The command will return a "ticket" string. | ||
2025 | You must give $TICKET to the requesting third party. | ||
2026 | |||
2027 | $RP_KEY is the public key of the third party and "attribute1,attribute2,..." is a comma-separated list of attribute names, such as "email,name,...", that you want to share. | ||
2028 | |||
2029 | The third party may retrieve the key in string format for use in the above | ||
2030 | call using "gnunet-identity": | ||
2031 | |||
2032 | @example | ||
2033 | $ RP_KEY=$(gnunet-identity -d | grep "relyingparty" | awk '@{print $3@}') | ||
2034 | @end example | ||
2035 | |||
2036 | The third party can then retrieve your shared identity attributes using: | ||
2037 | |||
2038 | @example | ||
2039 | $ gnunet-reclaim -e "relyingparty" -C "ticket" | ||
2040 | @end example | ||
2041 | |||
2042 | Where "relyingparty" is the name for the identity behind $RP_KEY that the | ||
2043 | requesting party is using. | ||
2044 | This will retrieve and list the shared identity attributes. | ||
2045 | The above command will also work if the user is currently offline since the attributes are retrieved from GNS. | ||
2046 | Further, $TICKET can be re-used later to retrieve up-to-date attributes in case "friend" has changed the value(s). For instance, because his email address changed. | ||
2047 | |||
2048 | To list all given authorizations (tickets) you can execute: | ||
2049 | @example | ||
2050 | $ gnunet-reclaim -e "user" -T | ||
2051 | @end example | ||
2052 | |||
2053 | @node Revoking Authorizations of Third Parties | ||
2054 | @subsection Revoking Authorizations of Third Parties | ||
2055 | |||
2056 | If you want to revoke the access of a third party to your attributes you can execute: | ||
2057 | |||
2058 | @example | ||
2059 | $ gnunet-reclaim -e "user" -R $TICKET | ||
2060 | @end example | ||
2061 | |||
2062 | This will prevent the third party from accessing the attribute in the future. | ||
2063 | Please note that if the third party has previously accessed the attribute, there is not way in which the system could have prevented the thiry party from storing the data. | ||
2064 | As such, only access to updated data in the future can be revoked. | ||
2065 | This behaviour is _exactly the same_ as with other IdPs. | ||
2066 | |||
2067 | @node OpenID Connect | ||
2068 | @subsection OpenID Connect | ||
2069 | |||
2070 | There is an @uref{OpenID Connect, https://openid.net/specs/openid-connect-core-1_0.html} API for use with re:claimID. | ||
2071 | However, its use is quite complicated to setup. | ||
2072 | |||
2073 | @example | ||
2074 | https://api.reclaim/openid/authorize | ||
2075 | http://localhost:7776/openid/token | ||
2076 | http://localhost:7776/openid/userinfo | ||
2077 | http://localhost:7776/openid/login | ||
2078 | @end example | ||
2079 | |||
2080 | The token endpoint is protected using HTTP basic authentication. | ||
2081 | You can authenticate using any username and the password configured under: | ||
2082 | |||
2083 | @example | ||
2084 | $ gnunet-config -s reclaim-rest-plugin -o OIDC_CLIENT_SECRET | ||
2085 | @end example | ||
2086 | |||
2087 | The authorize endpoint is protected using a Cookie which can be obtained through | ||
2088 | a request against the login endpoint. | ||
2089 | This functionality is meant to be used in the context of the OpenID Connect authorization | ||
2090 | flow to collect user consent interactively. | ||
2091 | Without a Cookie, the authorize endpoint redirects to a URI configured under: | ||
2092 | |||
2093 | @example | ||
2094 | $ gnunet-config -s reclaim-rest-plugin -o ADDRESS | ||
2095 | @end example | ||
2096 | |||
2097 | The token endpoint is protected using OAuth2 and expects the grant | ||
2098 | which is retrieved from the authorization endpoint according to the standard. | ||
2099 | |||
2100 | The userinfo endpoint is protected using OAuth2 and expects a bearer access | ||
2101 | token which is retrieved from a token request. | ||
2102 | |||
2103 | In order to make use of OpenID Connect flows as a user, you need to install | ||
2104 | the browser plugin: | ||
2105 | |||
2106 | @itemize @bullet | ||
2107 | @item @uref{https://addons.mozilla.org/addon/reclaimid/, Firefox Add-on} | ||
2108 | @item @uref{https://chrome.google.com/webstore/detail/reclaimid/jiogompmdejcnacmlnjhnaicgkefcfll, Chrome Web Store} | ||
2109 | @end itemize | ||
2110 | |||
2111 | In order to create and register an OpenID Connect client as a relying party, | ||
2112 | you need to execute the following steps: | ||
2113 | |||
2114 | @example | ||
2115 | $ gnunet-identity -C <client_name> | ||
2116 | $ gnunet-namestore -z <client_name> -a -n "@@" -t RECLAIM_OIDC_REDIRECT -V <redirect_uri> -e 1d -p | ||
2117 | $ gnunet-namestore -z <client_name> -a -n "@@" -t RECLAIM_OIDC_CLIENT -V "My OIDC Client" -e 1d -p | ||
2118 | @end example | ||
2119 | |||
2120 | The "client_id" for use in OpenID Connect is the public key of the client as | ||
2121 | displayed using: | ||
2122 | @example | ||
2123 | $ gnunet-identity -d grep "relyingparty" | awk '@{print $3@}' | ||
2124 | @end example | ||
2125 | |||
2126 | The RECLAIM_OIDC_REDIRECT record contains your website redirect URI. | ||
2127 | You may use any globally unique DNS or GNS URI. | ||
2128 | The RECLAIM_OIDC_CLIENT record represents the client description which whill | ||
2129 | be displayed to users in an authorization request. | ||
2130 | |||
2131 | Any website or relying party must use the authorization endpoint | ||
2132 | @uref{https://api.reclaim/openid/authorize} in its authorization redirects, e.g. | ||
2133 | |||
2134 | @example | ||
2135 | <a href="https://api.reclaim/openid/authorize?client_id=<PKEY>\ | ||
2136 | &scope=openid email\ | ||
2137 | &redirect_uri=<redirect_uri>\ | ||
2138 | &nonce=<random>">Login</a> | ||
2139 | @end example | ||
2140 | |||
2141 | This will direct the user's browser onto his local reclaimID instance. | ||
2142 | After giving consent, you will be provided with the OpenID Connect authorization | ||
2143 | code according to the specifications at your provided redirect URI. | ||
2144 | |||
2145 | The ID Tokens issues by the token endpoints are signed using HS512 with the | ||
2146 | shared secret configured under: | ||
2147 | |||
2148 | @example | ||
2149 | $ gnunet-config -s reclaim-rest-plugin -o JWT_SECRET | ||
2150 | @end example | ||
2151 | |||
2152 | The authorization code flow optionally supports @uref{https://tools.ietf.org/html/rfc7636, Proof Key for Code Exchange}. | ||
2153 | If PKCE is used, the client does not need to authenticate against the token | ||
2154 | endpoint. | ||
2155 | |||
2156 | @node Providing Third Party Attestation | ||
2157 | @subsection Providing Third Party Attestation | ||
2158 | |||
2159 | If you are running an identity provider (IdP) service you may be able to | ||
2160 | support providing credentials for re:claimID users. | ||
2161 | IdPs can issue JWT credentials as long as they support OpenID Connect and | ||
2162 | @uref{https://openid.net/specs/openid-connect-discovery-1_0.html,OpenID Connect Discovery}. | ||
2163 | |||
2164 | In order to allow users to import attributes through the re:claimID user interface, | ||
2165 | you need to register the following public OAuth2/OIDC client: | ||
2166 | |||
2167 | @itemize @bullet | ||
2168 | @item client_id: reclaimid | ||
2169 | @item client_secret: none | ||
2170 | @item redirect_uri: https://ui.reclaim (The URI of the re:claimID webextension) | ||
2171 | @item grant_type: authorization_code with PKCE (@uref{https://tools.ietf.org/html/rfc7636, RFC7636}) | ||
2172 | @item scopes: all you want to offer. | ||
2173 | @item id_token: JWT | ||
2174 | @end itemize | ||
2175 | |||
2176 | When your users add an attribute with name "email" which supports webfinger | ||
2177 | discovery they will be prompted with the option to retrieve the OpenID Connect | ||
2178 | ID Token through the user interface. | ||
2179 | |||
2180 | @node Using the Virtual Public Network | ||
2181 | @section Using the Virtual Public Network | ||
2182 | |||
2183 | @menu | ||
2184 | * Setting up an Exit node:: | ||
2185 | * Fedora and the Firewall:: | ||
2186 | * Setting up VPN node for protocol translation and tunneling:: | ||
2187 | @end menu | ||
2188 | |||
2189 | Using the GNUnet Virtual Public Network (VPN) application you can | ||
2190 | tunnel IP traffic over GNUnet. Moreover, the VPN comes | ||
2191 | with built-in protocol translation and DNS-ALG support, enabling | ||
2192 | IPv4-to-IPv6 protocol translation (in both directions). | ||
2193 | This chapter documents how to use the GNUnet VPN. | ||
2194 | |||
2195 | The first thing to note about the GNUnet VPN is that it is a public | ||
2196 | network. All participating peers can participate and there is no | ||
2197 | secret key to control access. So unlike common virtual private | ||
2198 | networks, the GNUnet VPN is not useful as a means to provide a | ||
2199 | "private" network abstraction over the Internet. The GNUnet VPN | ||
2200 | is a virtual network in the sense that it is an overlay over the | ||
2201 | Internet, using its own routing mechanisms and can also use an | ||
2202 | internal addressing scheme. The GNUnet VPN is an Internet | ||
2203 | underlay --- TCP/IP applications run on top of it. | ||
2204 | |||
2205 | The VPN is currently only supported on GNU/Linux systems. | ||
2206 | Support for operating systems that support TUN (such as FreeBSD) | ||
2207 | should be easy to add (or might not even require any coding at | ||
2208 | all --- we just did not test this so far). Support for other | ||
2209 | operating systems would require re-writing the code to create virtual | ||
2210 | network interfaces and to intercept DNS requests. | ||
2211 | |||
2212 | The VPN does not provide good anonymity. While requests are routed | ||
2213 | over the GNUnet network, other peers can directly see the source | ||
2214 | and destination of each (encapsulated) IP packet. Finally, if you | ||
2215 | use the VPN to access Internet services, the peer sending the | ||
2216 | request to the Internet will be able to observe and even alter | ||
2217 | the IP traffic. We will discuss additional security implications | ||
2218 | of using the VPN later in this chapter. | ||
2219 | |||
2220 | @node Setting up an Exit node | ||
2221 | @subsection Setting up an Exit node | ||
2222 | |||
2223 | Any useful operation with the VPN requires the existence of an exit | ||
2224 | node in the GNUnet Peer-to-Peer network. Exit functionality can only | ||
2225 | be enabled on peers that have regular Internet access. If you want | ||
2226 | to play around with the VPN or support the network, we encourage | ||
2227 | you to setup exit nodes. This chapter documents how to setup an | ||
2228 | exit node. | ||
2229 | |||
2230 | There are four types of exit functions an exit node can provide, | ||
2231 | and using the GNUnet VPN to access the Internet will only work | ||
2232 | nicely if the first three types are provided somewhere in | ||
2233 | the network. The four exit functions are: | ||
2234 | |||
2235 | @itemize @bullet | ||
2236 | @item DNS: allow other peers to use your DNS resolver | ||
2237 | @item IPv4: allow other peers to access your IPv4 Internet connection | ||
2238 | @item IPv6: allow other peers to access your IPv6 Internet connection | ||
2239 | @item Local service: allow other peers to access a specific TCP or | ||
2240 | UDP service your peer is providing | ||
2241 | @end itemize | ||
2242 | |||
2243 | By enabling "exit" in gnunet-setup and checking the respective boxes | ||
2244 | in the "exit" tab, you can easily choose which of the above exit | ||
2245 | functions you want to support. | ||
2246 | |||
2247 | Note, however, that by supporting the first three functions you will | ||
2248 | allow arbitrary other GNUnet users to access the Internet via your | ||
2249 | system. This is somewhat similar to running a Tor exit node. The | ||
2250 | Torproject has a nice article about what to consider if you want | ||
2251 | to do this here. We believe that generally running a DNS exit node | ||
2252 | is completely harmless. | ||
2253 | |||
2254 | The exit node configuration does currently not allow you to restrict the | ||
2255 | Internet traffic that leaves your system. In particular, you cannot | ||
2256 | exclude SMTP traffic (or block port 25) or limit to HTTP traffic using | ||
2257 | the GNUnet configuration. However, you can use your host firewall to | ||
2258 | restrict outbound connections from the virtual tunnel interface. This | ||
2259 | is highly recommended. In the future, we plan to offer a wider range | ||
2260 | of configuration options for exit nodes. | ||
2261 | |||
2262 | Note that by running an exit node GNUnet will configure your kernel | ||
2263 | to perform IP-forwarding (for IPv6) and NAT (for IPv4) so that the | ||
2264 | traffic from the virtual interface can be routed to the Internet. | ||
2265 | In order to provide an IPv6-exit, you need to have a subnet routed | ||
2266 | to your host's external network interface and assign a subrange of | ||
2267 | that subnet to the GNUnet exit's TUN interface. | ||
2268 | |||
2269 | When running a local service, you should make sure that the local | ||
2270 | service is (also) bound to the IP address of your EXIT interface | ||
2271 | (e.g. 169.254.86.1). It will NOT work if your local service is | ||
2272 | just bound to loopback. You may also want to create a "VPN" record | ||
2273 | in your zone of the GNU Name System to make it easy for others to | ||
2274 | access your service via a name instead of just the full service | ||
2275 | descriptor. Note that the identifier you assign the service can | ||
2276 | serve as a passphrase or shared secret, clients connecting to the | ||
2277 | service must somehow learn the service's name. VPN records in the | ||
2278 | GNU Name System can make this easier. | ||
2279 | |||
2280 | @node Fedora and the Firewall | ||
2281 | @subsection Fedora and the Firewall | ||
2282 | |||
2283 | |||
2284 | When using an exit node on Fedora 15, the standard firewall can | ||
2285 | create trouble even when not really exiting the local system! | ||
2286 | For IPv4, the standard rules seem fine. However, for IPv6 the | ||
2287 | standard rules prohibit traffic from the network range of the | ||
2288 | virtual interface created by the exit daemon to the local IPv6 | ||
2289 | address of the same interface (which is essentially loopback | ||
2290 | traffic, so you might suspect that a standard firewall would | ||
2291 | leave this traffic alone). However, as somehow for IPv6 the | ||
2292 | traffic is not recognized as originating from the local | ||
2293 | system (and as the connection is not already "established"), | ||
2294 | the firewall drops the traffic. You should still get ICMPv6 | ||
2295 | packets back, but that's obviously not very useful. | ||
2296 | |||
2297 | Possible ways to fix this include disabling the firewall (do you | ||
2298 | have a good reason for having it on?) or disabling the firewall | ||
2299 | at least for the GNUnet exit interface (or the respective | ||
2300 | IPv4/IPv6 address range). The best way to diagnose these kinds | ||
2301 | of problems in general involves setting the firewall to REJECT | ||
2302 | instead of DROP and to watch the traffic using wireshark | ||
2303 | (or tcpdump) to see if ICMP messages are generated when running | ||
2304 | some tests that should work. | ||
2305 | |||
2306 | @node Setting up VPN node for protocol translation and tunneling | ||
2307 | @subsection Setting up VPN node for protocol translation and tunneling | ||
2308 | |||
2309 | |||
2310 | The GNUnet VPN/PT subsystem enables you to tunnel IP traffic over the | ||
2311 | VPN to an exit node, from where it can then be forwarded to the | ||
2312 | Internet. This section documents how to setup VPN/PT on a node. | ||
2313 | Note that you can enable both the VPN and an exit on the same peer. | ||
2314 | In this case, IP traffic from your system may enter your peer's VPN | ||
2315 | and leave your peer's exit. This can be useful as a means to do | ||
2316 | protocol translation. For example, you might have an application that | ||
2317 | supports only IPv4 but needs to access an IPv6-only site. In this case, | ||
2318 | GNUnet would perform 4to6 protocol translation between the VPN (IPv4) | ||
2319 | and the Exit (IPv6). Similarly, 6to4 protocol translation is also | ||
2320 | possible. However, the primary use for GNUnet would be to access | ||
2321 | an Internet service running with an IP version that is not supported | ||
2322 | by your ISP. In this case, your IP traffic would be routed via GNUnet | ||
2323 | to a peer that has access to the Internet with the desired IP version. | ||
2324 | |||
2325 | Setting up an entry node into the GNUnet VPN primarily requires you | ||
2326 | to enable the "VPN/PT" option in "gnunet-setup". This will launch the | ||
2327 | "gnunet-service-vpn", "gnunet-service-dns" and "gnunet-daemon-pt" | ||
2328 | processes. The "gnunet-service-vpn" will create a virtual interface | ||
2329 | which will be used as the target for your IP traffic that enters the | ||
2330 | VPN. Additionally, a second virtual interface will be created by | ||
2331 | the "gnunet-service-dns" for your DNS traffic. You will then need to | ||
2332 | specify which traffic you want to tunnel over GNUnet. If your ISP only | ||
2333 | provides you with IPv4 or IPv6-access, you may choose to tunnel the | ||
2334 | other IP protocol over the GNUnet VPN. If you do not have an ISP | ||
2335 | (and are connected to other GNUnet peers via WLAN), you can also | ||
2336 | choose to tunnel all IP traffic over GNUnet. This might also provide | ||
2337 | you with some anonymity. After you enable the respective options | ||
2338 | and restart your peer, your Internet traffic should be tunneled | ||
2339 | over the GNUnet VPN. | ||
2340 | |||
2341 | The GNUnet VPN uses DNS-ALG to hijack your IP traffic. Whenever an | ||
2342 | application resolves a hostname (like 'gnunet.org'), the | ||
2343 | "gnunet-daemon-pt" will instruct the "gnunet-service-dns" to intercept | ||
2344 | the request (possibly route it over GNUnet as well) and replace the | ||
2345 | normal answer with an IP in the range of the VPN's interface. | ||
2346 | "gnunet-daemon-pt" will then tell "gnunet-service-vpn" to forward all | ||
2347 | traffic it receives on the TUN interface via the VPN to the original | ||
2348 | destination. | ||
2349 | |||
2350 | For applications that do not use DNS, you can also manually create | ||
2351 | such a mapping using the gnunet-vpn command-line tool. Here, you | ||
2352 | specify the desired address family of the result (e.g. "-4"), and the | ||
2353 | intended target IP on the Internet (e.g. "-i 131.159.74.67") and | ||
2354 | "gnunet-vpn" will tell you which IP address in the range of your | ||
2355 | VPN tunnel was mapped. | ||
2356 | |||
2357 | @command{gnunet-vpn} can also be used to access "internal" services | ||
2358 | offered by GNUnet nodes. So if you happen to know a peer and a | ||
2359 | service offered by that peer, you can create an IP tunnel to | ||
2360 | that peer by specifying the peer's identity, service name and | ||
2361 | protocol (--tcp or --udp) and you will again receive an IP address | ||
2362 | that will terminate at the respective peer's service. | ||
2363 | |||
2364 | @node Using the GNUnet Messenger | ||
2365 | @section Using the GNUnet Messenger | ||
2366 | |||
2367 | The GNUnet Messenger subsystem allows decentralized message-based | ||
2368 | communication inside of so called rooms. Each room can be hosted by | ||
2369 | a variable amount of peers. Every member of a room has the possibility | ||
2370 | to host the room on its own peer. A peer allows any amount of members | ||
2371 | to join a room. The amount of members in a room is not restricted. | ||
2372 | |||
2373 | Messages in a room will be distributed between all peers hosting the | ||
2374 | room or being internally (in context of the messenger service) connected | ||
2375 | to a hosting peer. All received or sent messages will be stored on any | ||
2376 | peer locally which is hosting the respective room or is internally | ||
2377 | connected to such a hosting peer. | ||
2378 | |||
2379 | The Messenger service is built on the CADET subsystem to make internal | ||
2380 | connections between peers using a reliable and encrypted transmission. | ||
2381 | Additionally the service uses a discrete padding to few different sizes. | ||
2382 | So kinds of messages and potential content can't be identified by the | ||
2383 | size of traffic from any attacker being unable to break the encryption | ||
2384 | of the transmission layer. | ||
2385 | |||
2386 | Another feature is additional end-to-end encryption for selected messages | ||
2387 | which uses the public key of another member (the receiver) to encrypt | ||
2388 | the message. Therefore it is ensured that only the selected member can | ||
2389 | read its content. This will also use additional padding. | ||
2390 | |||
2391 | @menu | ||
2392 | * Current state:: | ||
2393 | * Entering a room:: | ||
2394 | * Opening a room:: | ||
2395 | * Messaging in a room:: | ||
2396 | * Private messaging:: | ||
2397 | @end menu | ||
2398 | |||
2399 | @node Current state | ||
2400 | @subsection Current state | ||
2401 | |||
2402 | Currently there is only a simplistic CLI application available to use the | ||
2403 | messenger service. You can use this application with the | ||
2404 | @command{gnunet-messenger} command. | ||
2405 | |||
2406 | This application was designed for testing purposes and it does not provide | ||
2407 | full functionality in the current state. It is planned to replace this CLI | ||
2408 | application in later stages with a fully featured one using a client-side | ||
2409 | library designed for messenger applications. | ||
2410 | |||
2411 | @node Entering a room | ||
2412 | @subsection Entering a room | ||
2413 | |||
2414 | You can enter any room by its ROOMKEY and any PEERIDENTITY of a hosting peer. | ||
2415 | Optionally you can provide any IDENTITY which can represent a local ego by | ||
2416 | its name. | ||
2417 | |||
2418 | @example | ||
2419 | $ gnunet-messenger [-e IDENTITY] -d PEERIDENTITY -r ROOMKEY | ||
2420 | @end example | ||
2421 | |||
2422 | A PEERIDENTITY gets entered in encoded form. You can get your own peer ID by | ||
2423 | using the @command{gnunet-peerinfo} command: | ||
2424 | |||
2425 | @example | ||
2426 | $ gnunet-peerinfo -s | ||
2427 | @end example | ||
2428 | |||
2429 | A ROOMKEY gets entered in readable text form. The service will then hash the | ||
2430 | entered ROOMKEY and use the result as shared secret for transmission through | ||
2431 | the CADET submodule. You can also optionally leave out the '-r' parameter and | ||
2432 | the ROOMKEY to use the zeroed hash instead. | ||
2433 | |||
2434 | If no IDENTITY is provided you will not send any name to others, you will be | ||
2435 | referred as "anonymous" instead and use the anonymous ego. If you provide any | ||
2436 | IDENTITY a matching ego will be used to sign your messages. If there is no | ||
2437 | matching ego you will use the anonymous ego instead. The provided IDENTITY will | ||
2438 | be distributed as your name for the service in any case. | ||
2439 | |||
2440 | @node Opening a room | ||
2441 | @subsection Opening a room | ||
2442 | |||
2443 | You can open any room in a similar way to entering it. You just have to leave | ||
2444 | out the '-d' parameter and the PEERIDENTITY of the hosting peer. | ||
2445 | |||
2446 | @example | ||
2447 | $ gnunet-messenger [-e IDENTITY] -r ROOMKEY | ||
2448 | @end example | ||
2449 | |||
2450 | Providing ROOMKEY and IDENTITY is identical to entering a room. Opening a room | ||
2451 | will also make your peer to a host of this room. So others can enter the room | ||
2452 | through your peer if they have the required ROOMKEY and your peer ID. | ||
2453 | |||
2454 | If you want to use the zeroed hash as shared secret key for the room you can | ||
2455 | also leave it out as well: | ||
2456 | |||
2457 | @example | ||
2458 | $ gnunet-messenger | ||
2459 | @end example | ||
2460 | |||
2461 | @node Messaging in a room | ||
2462 | @subsection Messaging in a room | ||
2463 | |||
2464 | Once joined a room by entering it or opening it you can write text-based | ||
2465 | messages which will be distributed between all internally conntected peers. All | ||
2466 | sent messages will be displayed in the same way as received messages. | ||
2467 | |||
2468 | This relates to the internal handling of sent and received messages being mostly | ||
2469 | identical on application layer. Every handled message will be represented | ||
2470 | visually depending on its kind, content and sender. A sender can usually be | ||
2471 | identified by the encoded member ID or their name. | ||
2472 | |||
2473 | @example | ||
2474 | [17X37K] * 'anonymous' says: "hey" | ||
2475 | @end example | ||
2476 | |||
2477 | @node Private messaging | ||
2478 | @subsection Private messaging | ||
2479 | |||
2480 | As referred in the introduction the service allows sending private messages with | ||
2481 | additional end-to-end encryption. These messages will be visually represented | ||
2482 | by messages of the kind 'PRIVATE' in case they can't be decrypted with your used | ||
2483 | ego. Members who can't decrypt the message can potentially only identify its | ||
2484 | sender but they can't identify its receiver. | ||
2485 | |||
2486 | @example | ||
2487 | [17X37K] ~ message: PRIVATE | ||
2488 | @end example | ||
2489 | |||
2490 | If they can be decrypted they will appear as their secret message instead | ||
2491 | but marked visually. | ||
2492 | |||
2493 | @example | ||
2494 | [17X37K] ** 'anonymous' says: "hey" | ||
2495 | @end example | ||
2496 | |||
2497 | Currently you can only activate sending such encrypted text messages instead of | ||
2498 | usual text messages by adding the '-p' parameter: | ||
2499 | |||
2500 | @example | ||
2501 | $ gnunet-messenger [-e IDENTITY] -d PEERIDENTITY -r ROOMKEY -p | ||
2502 | @end example | ||
2503 | |||
2504 | Notice that you can only send such encrypted messages to members who use an ego | ||
2505 | which is not publicly known as the anonymous ego to ensure transparency. If | ||
2506 | any user could decrypt these messages they would not be private. So as receiver | ||
2507 | of such messages the IDENTITY is required and it has to match a local ego. | ||
2508 | |||