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author | Markus Teich <markus.teich@stusta.mhn.de> | 2016-06-08 13:04:53 +0200 |
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committer | Markus Teich <markus.teich@stusta.mhn.de> | 2016-06-08 13:04:53 +0200 |

commit | 8cf93a6c188d6a726bce46aa987c11611cf2baac (patch) | |

tree | 8272a5421243961f4fd73cd6915f500aa25c502c /gp-scripts | |

parent | 885b37bac1856c25d781b94eac88c03aef4e4a2b (diff) |

cleanup gp scripts

Diffstat (limited to 'gp-scripts')

-rw-r--r-- | gp-scripts/firstPrice | 91 | ||||

-rw-r--r-- | gp-scripts/smc.gp | 35 |

2 files changed, 126 insertions, 0 deletions

diff --git a/gp-scripts/firstPrice b/gp-scripts/firstPrice new file mode 100644 index 0000000..d936e36 --- /dev/null +++ b/gp-scripts/firstPrice @@ -0,0 +1,91 @@ +\\ 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 = 2^3 +\\ amount of possible prices +k = 2^7 +\\ 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) + +\\\\\\\\\\\\ +\\ 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 + +\\\\\\\\\\\\ +\\ 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/smc.gp b/gp-scripts/smc.gp new file mode 100644 index 0000000..2b7e188 --- /dev/null +++ b/gp-scripts/smc.gp @@ -0,0 +1,35 @@ +/* search for a random prime with the specified amount of bits */ +\\ randomprime(bits:small=127)= +\\ { +\\ local(r:int=4); +\\ while(!isprime(r), +\\ r = bitor(2^(bits-1) + random(2^(bits-1)-1), 1); +\\ ); +\\ r; +\\ } + +smc_hextodec(s:str) = +{ + local(v:vecsmall = Vecsmall(s), ret:int = 0); + for(i = 1, #v, + ret = (ret<<4) + if(v[i]<=57 && v[i]>=48, v[i]-48, v[i]<=70 && v[i]>=65, v[i]-55, v[i]<=102 && v[i]>=97, v[i]-87, error("invalid input format")) + ); + 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]); +} + + |