def encrypt(self, pk, m):
(k, ID, x) = encap.S(pk['pub'])
if type(m) != bytes:
m = bytes(m, 'utf8')
if type(x) != bytes:
x = bytes(x, 'utf8')
ID2 = group.hash(ID, ZR)
m2 = m + b':' + x
kprime = group.random(GT)
kprimeStr = self.elmtToString(kprime, len(m2))
C1 = ibenc.encrypt(pk['PK'], ID2, kprime)
C2 = self.str_XOR(m2, kprimeStr)
C2 = C2.encode('utf8')
C1prime = pickleObject(serializeObject(C1, group))
tag = hmac.new(k, C1prime+C2, hashlib.sha1).digest()
cipher = { 'ID':ID, 'C1':C1, 'C2':C2, 'tag':tag }
return cipher
def decrypt(self, pk, sk, c):
ID2 = group.hash(c['ID'], ZR)
SK = ibenc.extract(sk['msk'], ID2)
kprime = ibenc.decrypt(pk, SK, c['C1'])
kprimeStr = self.elmtToString(kprime, len(c['C2']))
m2 = self.str_XOR(c['C2'], kprimeStr)
x = m2.split(':')[1]
k = encap.R(pk['pub'], c['ID'], x)
C1prime = pickleObject(serializeObject(c['C1'], group))
if(c['tag'] == hmac.new(k, C1prime+c['C2'], hashlib.sha1).digest()):
return bytes(m2.split(':')[0], 'utf8')
else:
return b'FALSE'
