def compute_cipher (self, user, X, Y):
C = self.conc(X, Y)
dsa = DSA(self.point, self.n)
u, v, m = dsa.sign(user, C)
D = str(u) + '$' + str(v) + '$' + str(m)
u_cipher = encrypt_AES(user, D)
return u_cipher
def verify_cipher (self, user, cipher, X, Y):
D = decrypt_AES(user, cipher)
[u, v, C] = D.split('$')
u = int(u)
v = int(v)
if C != self.conc(Y, X):
return 1, "[STS ERROR] Received message is different from expected"
dsa = DSA(self.point, self.n)
nb, error_m = dsa.verify(Y, C, u, v)
if nb != 0:
return nb, error_m
return 0, "[STS] Verification OK, shared secret validated"
