def decryptMAABE(readFileGP, readFileUserSecretKey, readFileCipherText):
pickleFileGP = pickleLoad(readFileGP)
gp = byToOb(pickleFileGP)
gp.update({'H': H, 'F': F})
pickleFileUserSecretKey = pickleLoad(readFileUserSecretKey)
sk = byToOb(pickleFileUserSecretKey)
pickleFileCipherText = pickleLoad(readFileCipherText)
ct = byToOb(pickleFileCipherText)
policy = util.createPolicy(ct['policy'])
coefficients = util.getCoefficients(policy)
pruned_list = util.prune(policy, sk['keys'].keys())
if not pruned_list:
raise Exception(
"You don't have the required attributes for decryption!")
B = group.init(GT, 1)
for i in range(len(pruned_list)):
x = pruned_list[i].getAttribute() # without the underscore
y = pruned_list[i].getAttributeAndIndex() # with the underscore
B *= (ct['C1'][y] * pair(ct['C2'][y], sk['keys'][x]['K']) *
pair(ct['C3'][y], gp['H'](sk['GID'])) *
pair(sk['keys'][x]['KP'], ct['C4'][y]))**coefficients[y]
print("Decrypt")
# print("SK:")
# print(sk)
print("Decrypted AES Key using MAABE:")
print(ct['C0'] / B)
return ct['C0'] / B
def predecrypt(pk, ik, ct):
group = PairingGroup('SS512')
util = SecretUtil(group, debug)
w = pk['w']
u = pk['u']
S = ik['S'] #['THREE', 'ONE', 'TWO']
K0 = ik['K0']
K1 = ik['K1']
Kj2 = ik['Ki2']
Kj3 = ik['Ki3']
C0 = ct['C0']
Ci1 = ct['C_j_1']
Ci2 = ct['C_j_2']
Ci3 = ct['C_j_3']
Ci4 = ct['C_j_4']
Ci5 = ct['C_j_5']
policy = util.createPolicy(ct['policy']) #((ONE or THREE) and (TWO or FOUR))
print('policy in predecrypt===', policy)
print('S in predecrypt===', S)
pruned = util.prune(policy, S) #[ONE, TWO]
if pruned is False:
raise Exception('Prune error in pre-decrypt')
wi = util.getCoefficients(policy) #{u'TWO': <pairing.Element>, u'FOUR': <pairing.Element>, u'THREE': <pairing.Element>, u'ONE': <pairing.Element>}
eC0K0 = pair(C0,K0)
ECi4wi = 0
for each in pruned:
i = each.getAttribute()
ECi4wi += Ci4[i] * wi[i]
ewECi4wiK1 = pair(w ** ECi4wi,K1)
PIeCi1K1eCi2uCi5Kj2eCi3Kj3wi = 1
for each in pruned:
j = each.getAttributeAndIndex()
i = each.getAttribute()
eCi1K1 = pair(Ci1[i],K1)
eCi2uCi5Kj2 = pair(Ci2[i] * (u ** -Ci5[i]), Kj2[j])
eCi3Kj3 = pair(Ci3[i],Kj3[j])
PIeCi1K1eCi2uCi5Kj2eCi3Kj3wi *= (eCi1K1 * eCi2uCi5Kj2 * eCi3Kj3) ** wi[i]
return objectToBytes(eC0K0/(ewECi4wiK1 * PIeCi1K1eCi2uCi5Kj2eCi3Kj3wi), group)
def setup(self):
g = group.random(G1)
p = group.random(G1)
h = group.random(G1)
u = group.random(G1)
v = group.random(G1)
w = group.random(G1)
alpha = group.random()
e_gg_alpha = pair(g,g) ** alpha
pk = {'p':objectToBytes(p, group),
'g':objectToBytes(g, group),
'h':objectToBytes(h, group),
'u':objectToBytes(u, group),
'v':objectToBytes(v, group),
'w':objectToBytes(w, group),
'eggalpha':objectToBytes(e_gg_alpha, group)
}
msk = {'pk':pk,
'alpha':objectToBytes(alpha, group)}
return {'pk':pk, 'msk':msk}
def pair_prod(self, lhs, rhs):
"""takes two lists of G1 & G2 and computes a pairing product"""
return pair(lhs, rhs, self.Pairing)
def __randomGT(self):
if not hasattr(self, 'gt'):
self.gt = pair(self.random(G1), self.random(G2))
z = self.random(ZR)
return self.gt ** z
def __randomGT(self):
if not hasattr(self, 'gt'):
self.gt = pair(self.random(G1), self.random(G2))
z = self.random(ZR)
return self.gt ** z
def pair_prod(self, lhs, rhs):
"""takes two lists of G1 & G2 and computes a pairing product"""
return pair(lhs, rhs, self.Pairing)
def pair_prod(self, lhs, rhs):
return pair(lhs, rhs, self.Pairing)
def pair_prod(self, lhs, rhs):
return pair(lhs, rhs, self.Pairing)
def setup():
g1 = group.random(G1)
g2 = group.random(G2)
egg = pair(g1, g2)
gpWithoutHF = {'g1': g1, 'g2': g2, 'egg': egg}
return gpWithoutHF
C0 = ct['C0']
Ci1 = ct['C_j_1']
Ci2 = ct['C_j_2']
Ci3 = ct['C_j_3']
Ci4 = ct['C_j_4']
Ci5 = ct['C_j_5']
policy = util.createPolicy(ct['policy']) #((ONE or THREE) and (TWO or FOUR))
print('access policy of this file :', policy)
try:
pruned = util.prune(policy, S) #[ONE, TWO]
except Exception,e:
raise Exception('your attributes do not satisfy the policy!')
wi = util.getCoefficients(policy) #return {u'TWO': <pairing.Element>, u'FOUR': <pairing.Element>, u'THREE': <pairing.Element>, u'ONE': <pairing.Element>}
eC0K0 = pair(C0,K0)
ECi4wi = 0
for each in pruned:
i = each.getAttribute()
ECi4wi += Ci4[i] * wi[i]
ewECi4wiK1 = pair(w ** ECi4wi,K1)
PIeCi1K1eCi2uCi5Kj2eCi3Kj3wi = 1
for each in pruned:
j = each.getAttributeAndIndex()
i = each.getAttribute()
eCi1K1 = pair(Ci1[i],K1)
eCi2uCi5Kj2 = pair(Ci2[i] * (u ** -Ci5[i]), Kj2[j])
eCi3Kj3 = pair(Ci3[i],Kj3[j])
PIeCi1K1eCi2uCi5Kj2eCi3Kj3wi *= (eCi1K1 * eCi2uCi5Kj2 * eCi3Kj3) ** wi[i]
key_AES = (eC0K0/(ewECi4wiK1 * PIeCi1K1eCi2uCi5Kj2eCi3Kj3wi)) ** sk
