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author | Markus Teich <markus.teich@stusta.mhn.de> | 2016-06-08 15:40:22 +0200 |
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committer | Markus Teich <markus.teich@stusta.mhn.de> | 2016-06-08 15:40:22 +0200 |
commit | d4360a4f8b7d29aedf6f9af0a878a9060d434ea2 (patch) | |
tree | 40836708043afa8fb7c1a320e86e652fec44dd14 /gp-scripts | |
parent | 8cf93a6c188d6a726bce46aa987c11611cf2baac (diff) | |
download | libbrandt-d4360a4f8b7d29aedf6f9af0a878a9060d434ea2.tar.gz libbrandt-d4360a4f8b7d29aedf6f9af0a878a9060d434ea2.zip |
fix typos and types
Diffstat (limited to 'gp-scripts')
-rw-r--r-- | gp-scripts/m+1stPrice | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/gp-scripts/m+1stPrice b/gp-scripts/m+1stPrice new file mode 100644 index 0000000..8407e96 --- /dev/null +++ b/gp-scripts/m+1stPrice | |||
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1 | \\ From: "Fully private auctions in a constant number of rounds" (2003) by Felix Brandt pages 9-10 | ||
2 | |||
3 | |||
4 | \\\\\\\\\\\\ | ||
5 | \\ Adapt the following values to your needs | ||
6 | \\\\\\\\\\\\ | ||
7 | |||
8 | \\ amount of bidders | ||
9 | n = 2^3 | ||
10 | \\ amount of possible prices | ||
11 | k = 2^7 | ||
12 | \\ randomize bids (change to something static, if you like) | ||
13 | bid = vector(n,i,random(k)+1) | ||
14 | \\bid = vector(n,i,n-i+1) \\ first bidder wins | ||
15 | \\bid = vector(n,i,i) \\ last bidder wins | ||
16 | \\bid = vector(n,i,(i+1)%2) \\ second bidder wins (with ties) | ||
17 | |||
18 | \\ prime finite field setup (result may be ambiguous if your prime is too small, 4*n*k seems to work fine) | ||
19 | q = prime(4*n*k) | ||
20 | |||
21 | \\\\\\\\\\\\ | ||
22 | \\ SETUP | ||
23 | \\\\\\\\\\\\ | ||
24 | |||
25 | \\ p not needed? wat? | ||
26 | \\p = 47 | ||
27 | |||
28 | \\ get generator / primitive element for Z_q | ||
29 | var = 'x \\ copy pasta from internet | ||
30 | pe=ffgen(minpoly(ffprimroot(ffgen(ffinit(q,1))),var),var) \\ get primitive element | ||
31 | 1/(fforder(pe) == q-1) \\ error out, if ord(pe) is wrong | ||
32 | g = Mod(eval(Str(pe)), q) \\ dirty hack to convert t_FFELEM to t_INT | ||
33 | |||
34 | \\\\\\\\\\\\ | ||
35 | \\ PROLOG | ||
36 | \\\\\\\\\\\\ | ||
37 | |||
38 | \\ private keys of agents | ||
39 | x = vector(n,i,random(q)) | ||
40 | \\ public keyshares of agents | ||
41 | yshares = vector(n,i,g^x[i]) | ||
42 | \\ shared public key | ||
43 | y = prod(X=1,n,yshares[X]) | ||
44 | |||
45 | \\ first index level = owning agent id (additive share) | ||
46 | \\ second index level = agent id, price id | ||
47 | m = vector(n,i,matrix(n,k,a,b,random(q))) | ||
48 | |||
49 | \\ index = owning agent id, price id | ||
50 | r = matrix(n,k,i,j,random(q)) | ||
51 | \\ bid matrix | ||
52 | b = matrix(n,k,i,j,g^(bid[i]==j)) | ||
53 | |||
54 | \\\\\\\\\\\\ | ||
55 | \\ ROUND1 | ||
56 | \\\\\\\\\\\\ | ||
57 | |||
58 | \\ encrypted bids | ||
59 | alpha = matrix(n,k,i,j, b[i,j]*y^r[i,j]) | ||
60 | beta = matrix(n,k,i,j, g^r[i,j]) | ||
61 | |||
62 | \\\\\\\\\\\\ | ||
63 | \\ ROUND2 | ||
64 | \\\\\\\\\\\\ | ||
65 | |||
66 | \\ multiplicative shares | ||
67 | \\ first index level = owning agent id (multiplicative share) | ||
68 | \\ second index level = agent id, price id | ||
69 | Gamma = vector(n,a,matrix(n,k,i,j, ( prod(h=1,n,prod(d=j+1,k,alpha[h,d])) * prod(d=1,j-1,alpha[i,d]) * prod(h=1,i-1,alpha[h,j]) )^m[a][i,j] )) | ||
70 | Delta = vector(n,a,matrix(n,k,i,j, ( prod(h=1,n,prod(d=j+1,k, beta[h,d])) * prod(d=1,j-1, beta[i,d]) * prod(h=1,i-1, beta[h,j]) )^m[a][i,j] )) | ||
71 | |||
72 | \\\\\\\\\\\\ | ||
73 | \\ ROUND3 | ||
74 | \\\\\\\\\\\\ | ||
75 | |||
76 | \\ multiplicative shares (decryption) | ||
77 | \\ first index level = owning agent id (multiplicative share) | ||
78 | \\ second index level = agent id, price id | ||
79 | Phi = vector(n,a,matrix(n,k,i,j, prod(h=1,n,Delta[h][i,j])^x[a] )) | ||
80 | |||
81 | \\\\\\\\\\\\ | ||
82 | \\ EPILOG | ||
83 | \\\\\\\\\\\\ | ||
84 | |||
85 | \\ winner matrix | ||
86 | v = matrix(n,k,a,j, prod(i=1,n,Gamma[i][a,j]) / prod(i=1,n,Phi[i][a,j]) ) | ||
87 | |||
88 | vi = lift(v) | ||
89 | |||
90 | print("bids are: ", bid) | ||
91 | for(X=1,n, if(vecmin(vi[X,])==1, print("And the winner is ", X) )) | ||