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- import random
- load('../mpc/curve.sage')
- load('../mpc/ec_share.sage')
- def open_2pc(party0_share, party1_share):
- return party0_share + party1_share
- def verify_2pc_mac_check(party0_mac, party1_mac):
- assert party0_mac+party1_mac == 0
- global_key = random.randint(0, p)
- class AuthenticatedShare(object):
- """
- additive share
- """
- def __init__(self, share, source, party_id, mac=None, modifier=None):
- self.share = share
- self.mac = global_key * self.share if mac==None else mac
- self.public_modifier = 0 if modifier == None else modifier # carry out extra addition/subtraction by public scalars until opening
- self.party_id = party_id
- self.source = source
- def copy(self):
- return AuthenticatedShare(K(self.share), self.source, self.party_id, K(self.mac), K(self.public_modifier))
- def __repr__(self):
- return "share: %s, mac: %s"%(self.share, self.mac)
- # SPDZ mac authentication
- def authenticated_open(self, peer_authenticated_share):
- opened_share = open_2pc(self.share, peer_authenticated_share.share)
- mac_key = random.randint(0,global_key)
- mac_share = mac_key * (opened_share + self.public_modifier) - self.mac
- peer_mac_key = global_key - mac_key
- peer_mac_share = peer_mac_key * (opened_share + peer_authenticated_share.public_modifier) - peer_authenticated_share.mac
- #assert (mac_share + peer_mac_share) == 0
- return opened_share
- def sub_scalar(self, scalar, party_id):
- return AuthenticatedShare(self.share - scalar, self.mac, self.public_modifier + scalar) if party_id == 0 else AuthenticatedShare(self.share , self.mac, self.public_modifier + scalar)
- def add_scalar(self, scalar, party_id):
- return AuthenticatedShare(self.share + scalar, self.mac , self.public_modifier - scalar) if party_id ==0 else AuthenticatedShare(self.share, self.mac, self.public_modifier - scalar)
- def mul_scalar(self, scalar):
- return AuthenticatedShare(self.share * scalar, self.mac * scalar, self.public_modifier * scalar)
- def mul_point(self, point):
- return ECAuthenticatedShare(self.share * point, self.mac * point, self.public_modifier * point)
- def __add__(self, rhs):
- '''
- add additive shares
- '''
- return AuthenticatedShare(self.share + rhs.share, self.mac + rhs.mac, self.public_modifier + rhs.public_modifier)
- def __sub__(self, rhs):
- '''
- sub additive shares
- '''
- return AuthenticatedShare(self.share - rhs.share, self.mac - rhs.mac, self.public_modifier - rhs.public_modifier)
- class MultiplicationAuthenticatedShares(object):
- def __init__(self, alpha, beta, triplet, party_id):
- # authenticated shares
- self.alpha_as = alpha
- self.beta_as = beta
- self.a_as = triplet[0]
- self.b_as = triplet[1]
- self.c_as = triplet[2]
- self.party_id = party_id
- d1 = self.alpha_as - self.a_as
- e1 = self.beta_as - self.b_as
- self.d = d1
- self.e = e1
- def mul(self, d2, e2):
- d = open_2pc(self.d.share, d2.share)
- e = open_2pc(self.e.share, e2.share)
- if self.party_id==0:
- bd = self.b_as.mul_scalar(d)
- ae = self.a_as.mul_scalar(e)
- return (bd + ae + self.c_as).add_scalar(d*e, self.party_id)
- else:
- bd = self.b_as.mul_scalar(d)
- ae = self.a_as.mul_scalar(e)
- #return (bd + ae + self.c_as).add_scalar(d*e, self.party_id)
- return bd + ae + self.c_as
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