diff --git a/gp-scripts/firstPrice b/gp-scripts/firstPrice deleted file mode 100644 index c638f4a..0000000 --- a/gp-scripts/firstPrice +++ /dev/null @@ -1,95 +0,0 @@ -\\ From: "How to obtain full privacy in auctions" (2006) by Felix Brandt pages 19-20 - - -\\\\\\\\\\\\ -\\ Adapt the following values to your needs -\\\\\\\\\\\\ - -\\ amount of bidders -n = 4 -\\ amount of possible prices -k = 2^4 -\\ randomize bids (change to something static, if you like) -bid = vector(n,i,random(k)+1) -\\bid = vector(n,i,n-i+1) \\ first bidder wins -\\bid = vector(n,i,i) \\ last bidder wins -\\bid = vector(n,i,(i+1)%2) \\ second bidder wins (with ties) - -\\ prime finite field setup (result may be ambiguous if your prime is too small, 4*n*k seems to work fine) -\\q = prime(4*n*k) -\\ 2048bit prime: -\\q = 31905233907400964621684499856844075173802000556075101303613351426740101897961025481077892281365444367883091980681462491724119317344478120131982416132058173572772607966572720945691237876256074322291459510766147107539260048324345382562673904236506104922357079761457605045674628331006193183908801308817507027556440703972646885207099302085383887085776295396030033300833460743425162726394704256227108175491673135830378272029374848904772902525385997099641162537271298634032011458617811670193865244028195169383991286227040469186123958053863978710424421008752927011390777187889943940479064193231486057910586526439884046593027 -\\ 3072bit prime: -q = 5175054779340588353586849786144680366505563673837334790820581054294754700842534366479020240016540005621125885927641963390708863183739793208880756653713659686139600715884857385144475261507869935694699816011948585170171332029002674283854825650901258017026965486602158722052719421343475066067509485302858041368266332080773331946039572497794442067057597327877030322029413318847025776818839927761556478107499002213648377029201340152459685610920194363099878398871001275336711869213616313858200583491913270052111910410231060407633125816386053759634073500319223989240814564691163285769745840521560940666058800931070258886096469889796899266014106833050284032035948051974659796051419431527095503586817863043771919051402039741075037010264761045992285666560487072740505566408086913711094879155498223636912657852688296081316652278801546924079650897913388978423388839346058027184069633227966507908979049369500450630036982661231208087459099 - -\\\\\\\\\\\\ -\\ SETUP -\\\\\\\\\\\\ - -\\ p not needed? wat? -\\p = 47 - -\\ get generator / primitive element for Z_q -\\ var = 'x \\ copy pasta from internet -\\ pe=ffgen(minpoly(ffprimroot(ffgen(ffinit(q,1))),var),var) \\ get primitive element -\\ 1/(fforder(pe) == q-1) \\ error out, if ord(pe) is wrong -\\ g = Mod(eval(Str(pe)), q) \\ dirty hack to convert t_FFELEM to t_INT -g = Mod(2, q) - -\\\\\\\\\\\\ -\\ PROLOG -\\\\\\\\\\\\ - -\\ private keys of agents -x = vector(n,i,random(q)) -\\ public keyshares of agents -yshares = vector(n,i,g^x[i]) -\\ shared public key -y = prod(X=1,n,yshares[X]) - -\\ first index level = owning agent id (additive share) -\\ second index level = agent id, price id -m = vector(n,i,matrix(n,k,a,b,random(q))) - -\\ index = owning agent id, price id -r = matrix(n,k,i,j,random(q)) -\\ bid matrix -b = matrix(n,k,i,j,g^(bid[i]==j)) - -\\\\\\\\\\\\ -\\ ROUND1 -\\\\\\\\\\\\ - -\\ encrypted bids -alpha = matrix(n,k,i,j, b[i,j]*y^r[i,j]) -beta = matrix(n,k,i,j, g^r[i,j]) - -\\\\\\\\\\\\ -\\ ROUND2 -\\\\\\\\\\\\ - -\\ multiplicative shares -\\ first index level = owning agent id (multiplicative share) -\\ second index level = agent id, price id -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] )) -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] )) - -\\\\\\\\\\\\ -\\ ROUND3 -\\\\\\\\\\\\ - -\\ multiplicative shares (decryption) -\\ first index level = owning agent id (multiplicative share) -\\ second index level = agent id, price id -Phi = vector(n,a,matrix(n,k,i,j, prod(h=1,n,Delta[h][i,j])^x[a] )) - -\\\\\\\\\\\\ -\\ EPILOG -\\\\\\\\\\\\ - -\\ winner matrix -v = matrix(n,k,a,j, prod(i=1,n,Gamma[i][a,j]) / prod(i=1,n,Phi[i][a,j]) ) -vi = lift(v) - -print("bids are: ", bid) -for(X=1,n, if(vecmin(vi[X,])==1, print("And the winner is ", X) )) diff --git a/gp-scripts/firstPrice.gp b/gp-scripts/firstPrice.gp new file mode 100644 index 0000000..5642fa0 --- /dev/null +++ b/gp-scripts/firstPrice.gp @@ -0,0 +1,186 @@ +\\ From: "How to obtain full privacy in auctions" (2006) by Felix Brandt pages 19-20 + + +\\\\\\\\\\\\ +\\ Adapt the following values to your needs +\\\\\\\\\\\\ + +\\ amount of bidders +n = 3 +\\ amount of possible prices +k = 2^2 +\\ randomize bids (change to something static, if you like) +bid = vector(n,i,random(k)+1) +\\bid = vector(n,i,n-i+1) \\ first bidder wins +\\bid = vector(n,i,i) \\ last bidder wins +\\bid = vector(n,i,(i+1)%2) \\ second bidder wins (with ties) + +\\\\\\\\\\\\ +\\ SETUP +\\\\\\\\\\\\ + +read(group) +read(zkp) + +\\\\\\\\\\\\ +\\ PROLOG +\\\\\\\\\\\\ + +\\ private keys of agents +x = vector(n,i,random(q)) +\\ first index level = owning agent id (additive share) +\\ second index level = agent id, price id +m = vector(n,i,matrix(n,k,a,b,random(q))) + +\\ zkp +proofs1 = vector(n,i,zkp1_proof(G, x[i])) + +\\ public keyshares of agents +yshares = vector(n,i,proofs1[i][4]) +\\yshares = vector(n,i,G^x[i]) + +\\ for performance evaluations we need to check the proofs for every bidder +\\ i := checking bidder (0 == seller) +\\ h := bidder to check +{ +for(i=0,n, + for(h=1,n, + if(1 != zkp1_check(proofs1[h]), + error("zkp1 failure in round0") + ) + ) +) +} + +\\ shared public key +y = prod(X=1,n,yshares[X]) + +\\\\\\\\\\\\ +\\ ROUND1 +\\\\\\\\\\\\ + +\\ bid matrix +b = matrix(n,k,i,j,G^(bid[i]==j)) + +\\ zkp +proofs3 = matrix(n,k,i,j, zkp3_proof(G,y,G^(bid[i]==j))) + +\\ index = owning agent id, price id +r = matrix(n,k,i,j,proofs3[i,j][13]) +\\r = matrix(n,k,i,j,random(q)) + +\\ encrypted bids +Alpha = matrix(n,k,i,j, proofs3[i,j][3]) +Beta = matrix(n,k,i,j, proofs3[i,j][4]) +\\Alpha = matrix(n,k,i,j, b[i,j]*y^r[i,j]) +\\Beta = matrix(n,k,i,j, G^r[i,j]) + +proofs2 = vector(n,i, zkp2_proof(y,G,sum(j=1,k, r[i,j]))) +\\ i := checking bidder (0 == seller) +\\ h := bidder to check +\\ j := price index to check +{ +for(i=0,n, + for(h=1,n, + for(j=1,k, + if(1 != zkp3_check(proofs3[h,j]), + error("zkp3 failure in round1") + ) + ); + if((prod(j=1,k,Alpha[h,j])/G) != proofs2[h][6], + error("alpha product doesn't match") + ); + if(prod(j=1,k,Beta[h,j]) != proofs2[h][7], + error("beta product doesn't match") + ); + if(1 != zkp2_check(proofs2[h]), + error("zkp2 failure in round1") + ) + ) +) +} + +\\\\\\\\\\\\ +\\ ROUND2 +\\\\\\\\\\\\ + +\\ multiplicative shares +\\ first index level = owning agent id (multiplicative share) +\\ second index level = agent id, price id +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]) )) +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]) )) +\\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] )) +\\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] )) + +\\ random masking and zkp +proofs2 = vector(n,a,matrix(n,k,i,j, zkp2_proof(Gamma[a][i,j], Delta[a][i,j], random(q)) )) + +\\ for performance evaluations we need to check the proofs for every bidder +\\ i := checking bidder (0 == seller) +\\ h := bidder to check +\\ t := target bidder (creator of the proof) +\\ j := price +{ +for(t=1,n, + for(h=1,n, + for(j=1,k, + for(i=0,n, + if(1 != zkp2_check(proofs2[t][h,j]), + error("zkp2 failure in round2") + ) + ); + \\ use masked values generated during the zkp + Gamma[t][h,j] = proofs2[t][h,j][6]; + Delta[t][h,j] = proofs2[t][h,j][7]; + ) + ) +) +} + + +\\\\\\\\\\\\ +\\ ROUND3 +\\\\\\\\\\\\ + +\\ multiplicative shares (decryption) +\\ first index level = owning agent id (multiplicative share) +\\ second index level = agent id, price id +Phi = vector(n,a,matrix(n,k,i,j, prod(h=1,n,Delta[h][i,j]) )) +\\Phi = vector(n,a,matrix(n,k,i,j, prod(h=1,n,Delta[h][i,j])^x[a] )) + +proofs2 = vector(n,a,matrix(n,k,i,j, zkp2_proof(Phi[a][i,j], G, x[a]) )) + +\\ for performance evaluations we need to check the proofs for every bidder +\\ i := checking bidder (0 == seller) +\\ h := bidder to check +\\ t := target bidder (creator of the proof) +\\ j := price +{ +for(t=1,n, + for(h=1,n, + for(j=1,k, + for(i=0,n, + if(1 != zkp2_check(proofs2[t][h,j]), + error("zkp2 failure in round2") + ) + ); + \\ use masked values generated during the zkp + Phi[t][h,j] = proofs2[t][h,j][6]; + ) + ) +) +} + + +\\\\\\\\\\\\ +\\ EPILOG +\\\\\\\\\\\\ + +\\ winner matrix +v = matrix(n,k,a,j, prod(i=1,n,Gamma[i][a,j]) / prod(i=1,n,Phi[i][a,j]) ) +vi = lift(v) + +print("bids are: ", bid) +for(X=1,n, if(vecmin(vi[X,])==1, print("And the winner is ", X) )) + +; diff --git a/gp-scripts/group.gp b/gp-scripts/group.gp new file mode 100644 index 0000000..3f941b8 --- /dev/null +++ b/gp-scripts/group.gp @@ -0,0 +1,15 @@ +\\ p generated by ssh-keygen from the following moduli(5) line: +\\ 20161024184335 2 6 100 3071 2 C63A6E912985E56A40FA7747D856C9FFD01B052F0BDEA89F0B17C34EC168E918FCC6121351CA0003453E96EBB5CE228D97610D0F7AA0EE1EC26124723BDA68607D0348B30A39B92DFBB4E23219DA3440756C169A4F1B929DDB487CF2C53520910C800340DE87CA65D2041FA393FD0D25019589B7ED89D0AD256764FF690B122FC868ED5E314346CA93505700B650BDD74D6395767E67AA4E29517699A2170892B572EC6050FD4F0545FE981D9583CD47411788ADFD7C60B33E6A186FCAE5ACAF8CE012B5551A3A54B15AA28D4F7C3EF37220819CA180B3BA855D816FF5D3AC0A8D2AB4E0C9D638C785F0E2707B591326A6E657F3E26D9EEDE5760E81165B0B3680ADA447AFE0A31EA9A31CC1825EB9B36AF746FB579A0A327AEF54D16B1C7A1575A241139F9B8551EA3C687E2E333ABDA9E5F491CA7F1611E478F8B4FA74E34A6771374198FE337634E8B0021BA826BF332818BB43052B6BC6D84E4E34BD1ABEC166881CC69079ED1F306C7143C5F9E341C6955DD501ED51FCE5F7F94CFA6273 +\\ This is a "safe prime", see moduli(5) +\\ Therefore q = (p-1)/2 is also prime + +p = 4498546982183741806042046874925230841367752610105215768946438255470120740195522849201856997179866815126313339756915558167423398334072639778026401904031844016861682960881473450120265256327641310709437833580886250441164652551031655405301329413885250587408573319621138304678094611598436119854035881555472079889364307701983275427495796082239390426306590239630071293304476993188112145295406185504400770379250448236759388051149856191572199475958274963892549036586332373555561624378385324018563641781073722121282924048194073332885386583853286835384896286468480594489851988635137146304050743119406030150457214703115428415028345445439080824905967347767410065096124691155434106090788541491301971510767072678641286317388382884979008351941634738407020421109176416998181365911697340148847292136114015951382836045342314909586957351991419538245920973429697625016569947794803114551396527414933624103391788313038751051589980762413698400281203 + +\\ From that we can compute the subgroup-order prime q: +q = (p-1)/2 + +\\ Cyclic Subgroups of Z_p must have order 1, 2, q or p-1 +\\ => The generator of Subgroup Z_p^* is 3 as we can check with G^q == Mod(1, p) +G = Mod(3, p) + +; diff --git a/gp-scripts/smc.gp b/gp-scripts/smc.gp index 2b7e188..f32f5f2 100644 --- a/gp-scripts/smc.gp +++ b/gp-scripts/smc.gp @@ -17,19 +17,3 @@ smc_hextodec(s:str) = ret; } -smc_genbid(k:small, bid:small, g)= -{ - vector(k,j,g^(bid==j)); -} - -smc_genalpha(k:small, b:vec, r:vec, y)= -{ - vector(k, j, b[j]*y^r[j]); -} - -smc_genbeta(k:small, r:vec, g)= -{ - vector(k, j, g^r[j]); -} - - diff --git a/gp-scripts/zkp.gp b/gp-scripts/zkp.gp new file mode 100644 index 0000000..9bf7b7d --- /dev/null +++ b/gp-scripts/zkp.gp @@ -0,0 +1,129 @@ +\\ zero knowledge proofs + +read(group); + +\\ Don't use in production code! +\\ This is a very stupid implementation only used in performance evaluation. +kdf(in:vec) = +{ + prod(h=1,length(in),lift(in[h]))%q +} + + +zkp1_proof(G:intmod, x:int) = +{ + local(V:intmod, z:int, A:intmod, c:int, r:int); + V = G^x; + z = random(q); + A = G^z; + c = kdf([G, V, A]); + r = (z+c*x)%q; + [G, r, A, V] +} + +zkp1_check(P:vec) = +{ + local(c:int, G:intmod, r:int, A:intmod, V:intmod); + if (length(P) < 4, error("Proof1 too short.")); + if (type(P[1]) == "t_INTMOD", G = P[1], error("P[1] has wrong type.")); + if (type(P[2]) == "t_INT", r = P[2], error("P[2] has wrong type.")); + if (type(P[3]) == "t_INTMOD", A = P[3], error("P[3] has wrong type.")); + if (type(P[4]) == "t_INTMOD", V = P[4], error("P[4] has wrong type.")); + c = kdf([G, V, A]); + G^r == A*V^c +} + + +zkp2_proof(G1:intmod, G2:intmod, x:int) = +{ + local(V:intmod, W:intmod, z:int, A:intmod, B:intmod, c:int, r:int); + V = G1^x; + W = G2^x; + z = random(q); + A = G1^z; + B = G2^z; + c = kdf([G1, G2, V, W, A, B]); + r = (z+c*x)%q; + [G1, G2, r, A, B, V, W] +} + +zkp2_check(P:vec) = +{ + local(c:int, + G1:intmod, G2:intmod, r:int, A:intmod, B:intmod, V:intmod, W:intmod); + if (length(P) < 7, error("Proof2 too short.")); + if (type(P[1]) == "t_INTMOD", G1 = P[1], error("P[1] has wrong type.")); + if (type(P[2]) == "t_INTMOD", G2 = P[2], error("P[2] has wrong type.")); + if (type(P[3]) == "t_INT", r = P[3], error("P[3] has wrong type.")); + if (type(P[4]) == "t_INTMOD", A = P[4], error("P[4] has wrong type.")); + if (type(P[5]) == "t_INTMOD", B = P[5], error("P[5] has wrong type.")); + if (type(P[6]) == "t_INTMOD", V = P[6], error("P[6] has wrong type.")); + if (type(P[7]) == "t_INTMOD", W = P[7], error("P[7] has wrong type.")); + c = kdf([G1, G2, V, W, A, B]); + G1^r == A*V^c && G2^r == B*W^c +} + + +zkp3_proof(G:intmod, Y:intmod, M:intmod) = +{ + local(Alpha:intmod, Beta:intmod, A1:intmod, A2:intmod, B1:intmod, B2:intmod, + d1:int, d2:int, r1:int, r2:int, w:int, r:int); + r = random(q); + Alpha = M*Y^r; + Beta = G^r; + if (M == Mod(1, p), + d1 = random(q); + r1 = random(q); + w = random(q); + A1 = G^r1 * Beta^d1; + B1 = Y^r1 * (Alpha / G)^d1; + A2 = G^w; + B2 = Y^w; + c = kdf([G, Alpha, Beta, A1, A2, B1, B2]); + d2 = (c - d1) % q; + r2 = (w - r*d2) % q; + , + if (M == G, + d2 = random(q); + r2 = random(q); + w = random(q); + A1 = G^w; + B1 = Y^w; + A2 = G^r2 * Beta^d2; + B2 = Y^r2 * Alpha^d2; + c = kdf([G, Alpha, Beta, A1, A2, B1, B2]); + d1 = (c - d2) % q; + r1 = (w - r*d1) % q; + , error("M is neither 1 nor G") + ) + ); + [G, Y, Alpha, Beta, A1, A2, B1, B2, d1, d2, r1, r2, r] +} + +zkp3_check(P:vec) = +{ + local(c:int, + G:intmod, Y:intmod, Alpha:intmod, Beta:intmod, A1:intmod, A2:intmod, B1:intmod, B2:intmod, + d1:int, d2:int, r1:int, r2:int); + if (length(P) < 12, error("Proof3 too short.")); + if (type(P[1] ) == "t_INTMOD", G = P[1], error("P[1] has wrong type.")); + if (type(P[2] ) == "t_INTMOD", Y = P[2], error("P[2] has wrong type.")); + if (type(P[3] ) == "t_INTMOD", Alpha = P[3], error("P[3] has wrong type.")); + if (type(P[4] ) == "t_INTMOD", Beta = P[4], error("P[4] has wrong type.")); + if (type(P[5] ) == "t_INTMOD", A1 = P[5], error("P[5] has wrong type.")); + if (type(P[6] ) == "t_INTMOD", A2 = P[6], error("P[6] has wrong type.")); + if (type(P[7] ) == "t_INTMOD", B1 = P[7], error("P[7] has wrong type.")); + if (type(P[8] ) == "t_INTMOD", B2 = P[8], error("P[8] has wrong type.")); + if (type(P[9] ) == "t_INT", d1 = P[9], error("P[9] has wrong type.")); + if (type(P[10]) == "t_INT", d2 = P[10], error("P[10] has wrong type.")); + if (type(P[11]) == "t_INT", r1 = P[11], error("P[11] has wrong type.")); + if (type(P[12]) == "t_INT", r2 = P[12], error("P[12] has wrong type.")); + c = kdf([G, Alpha, Beta, A1, A2, B1, B2]); + c == (d1 + d2) % q && + A1 == G^r1 * Beta^d1 && + A2 == G^r2 * Beta^d2 && + B1 == Y^r1 * (Alpha / G)^d1 && + B2 == Y^r2 * Alpha^d2 +} + +;