commit 3d0b7cab3e273dd2f3f3d8990fb868b93b6b3f95
parent db7da66be57c6a9df87f3ea1f3cd681539ad9b51
Author: Bernd Fix <brf@hoi-polloi.org>
Date: Wed, 1 Apr 2020 21:53:16 +0200
Adjusted revocation PoW to draft specification.
Diffstat:
3 files changed, 44 insertions(+), 31 deletions(-)
diff --git a/src/cmd/pow-test/main.go b/src/cmd/pow-test/main.go
@@ -1,6 +1,7 @@
package main
import (
+ "encoding/hex"
"flag"
"fmt"
"log"
@@ -19,7 +20,11 @@ func main() {
flag.IntVar(&bits, "b", 25, "Number of leading zero bits")
flag.BoolVar(&quiet, "q", false, "Be quiet")
flag.Parse()
+
+ // pre-set difficulty
fmt.Printf("Leading zeros required: %d\n", bits)
+ difficulty := math.TWO.Pow(512 - bits).Sub(math.ONE)
+ fmt.Printf("==> Difficulty: %v\n", difficulty)
// generate a random key pair
pkey, _ := ed25519.NewKeypair()
@@ -27,9 +32,6 @@ func main() {
// initialize RevData structure
rd := revocation.NewRevData(0, pkey)
- // pre-set difficulty
- difficulty := math.TWO.Pow(512 - bits).Sub(math.ONE)
-
var count uint64 = 0
for {
result, err := rd.Compute()
@@ -45,4 +47,5 @@ func main() {
}
fmt.Printf("PoW found after %d iterations:\n", count)
fmt.Printf("--> Nonce=%d\n", rd.GetNonce())
+ fmt.Printf(" REV = %s\n", hex.EncodeToString(rd.GetBlob()))
}
diff --git a/src/gnunet/service/context.go b/src/gnunet/service/context.go
@@ -30,28 +30,38 @@ import (
// by a service; the session is handled by the 'ServeClient' method of a
// service implementation.
type SessionContext struct {
- Id int // session identifier
- wg *sync.WaitGroup // wait group for the session
- sig *concurrent.Signaller // signaller for the session
- pending int // number of pending go-routines
+ Id int // session identifier
+ wg *sync.WaitGroup // wait group for the session
+ sig *concurrent.Signaller // signaller for the session
+ pending int // number of pending go-routines
+ active bool // is the context active (un-cancelled)?
+ onCancel *sync.Mutex // only run one Cancel() at a time
}
// NewSessionContext instantiates a new session context.
func NewSessionContext() *SessionContext {
return &SessionContext{
- Id: util.NextID(),
- wg: new(sync.WaitGroup),
- sig: concurrent.NewSignaller(),
- pending: 0,
+ Id: util.NextID(),
+ wg: new(sync.WaitGroup),
+ sig: concurrent.NewSignaller(),
+ pending: 0,
+ active: true,
+ onCancel: new(sync.Mutex),
}
}
// Cancel all go-routines associated with this context.
func (ctx *SessionContext) Cancel() {
- // send signal to terminate...
- ctx.sig.Send(true)
- // wait for session go-routines to finish
- ctx.wg.Wait()
+ ctx.onCancel.Lock()
+ if ctx.active {
+ // we are going out-of-business
+ ctx.active = false
+ // send signal to terminate...
+ ctx.sig.Send(true)
+ // wait for session go-routines to finish
+ ctx.wg.Wait()
+ }
+ ctx.onCancel.Unlock()
}
// Add a go-routine to the wait group.
diff --git a/src/gnunet/service/revocation/pow.go b/src/gnunet/service/revocation/pow.go
@@ -20,12 +20,12 @@ package revocation
import (
"bytes"
+ "crypto/cipher"
"crypto/sha256"
"crypto/sha512"
"encoding/binary"
"sync"
- "gnunet/crypto"
"gnunet/util"
"github.com/bfix/gospel/crypto/ed25519"
@@ -33,6 +33,7 @@ import (
"github.com/bfix/gospel/math"
"golang.org/x/crypto/hkdf"
"golang.org/x/crypto/scrypt"
+ "golang.org/x/crypto/twofish"
)
//----------------------------------------------------------------------
@@ -73,6 +74,11 @@ func (r *RevData) GetNonce() uint64 {
return r.Nonce
}
+// GetBlob returns the binary representation of RevData
+func (r *RevData) GetBlob() []byte {
+ return r.blob
+}
+
// Next selects the next nonce to be tested.
func (r *RevData) Next() {
var incr func(pos int)
@@ -91,33 +97,27 @@ func (r *RevData) Next() {
func (r *RevData) Compute() (*math.Int, error) {
// generate key material
- k, err := scrypt.Key(r.blob, []byte("gnunet-revocation-proof-of-work"), 2, 8, 2, 64)
+ k, err := scrypt.Key(r.blob, []byte("gnunet-revocation-proof-of-work"), 2, 8, 2, 32)
if err != nil {
return nil, err
}
- // generate keys
- skey := crypto.NewSymmetricKey()
- copy(skey.AESKey, k[:32])
- copy(skey.TwofishKey, k[32:])
-
// generate initialization vector
- iv := crypto.NewSymmetricIV()
- prk := hkdf.Extract(sha512.New, k[:32], []byte("gnunet-proof-of-work-ivAES!"))
+ iv := make([]byte, 16)
+ prk := hkdf.Extract(sha512.New, k, []byte("gnunet-proof-of-work-iv"))
rdr := hkdf.Expand(sha256.New, prk, []byte("gnunet-revocation-proof-of-work"))
- rdr.Read(iv.AESIv)
- prk = hkdf.Extract(sha512.New, k[32:], []byte("gnunet-proof-of-work-ivFISH"))
- rdr = hkdf.Expand(sha256.New, prk, []byte("gnunet-revocation-proof-of-work"))
- rdr.Read(iv.TwofishIv)
+ rdr.Read(iv)
- // perform encryption
- enc, err := crypto.SymmetricEncrypt(r.blob, skey, iv)
+ // Encrypt with Twofish CFB stream cipher
+ out := make([]byte, len(r.blob))
+ tf, err := twofish.NewCipher(k)
if err != nil {
return nil, err
}
+ cipher.NewCFBEncrypter(tf, iv).XORKeyStream(out, r.blob)
// compute result
- result, err := scrypt.Key(enc, []byte("gnunet-revocation-proof-of-work"), 2, 8, 2, 64)
+ result, err := scrypt.Key(out, []byte("gnunet-revocation-proof-of-work"), 2, 8, 2, 64)
return math.NewIntFromBytes(result), nil
}
