def obtainKey(self, request, cert):
key = self.decrypt(algs.int_repr(request['Key']))
signature = self.decrypt(algs.int_repr(request['Signature']))
length = request['Length']
verified = self.verifyKey(key, signature, cert)
if verified:
self.__obtained_keys.append(
{'Key': algs.hex_repr(key, length), 'From': cert})
return {
'verified': verified,
'key': algs.hex_repr(key, length)
}
def verify(self, letter, cert):
e = cert['Public Key Info']['Exponent']
n = algs.int_repr(cert['Public Key Info']['Modulus'])
if type(letter['Message']) == str:
msg = letter['Message'].encode('utf-8')
sign = algs.int_repr(letter['Signature'])
md5 = hashlib.md5(msg)
msg = md5.digest()
if msg == pow(sign, e, n).to_bytes(16, 'big'):
return True
else:
return False
def encrypt(self, msg, cert):
e = cert['Public Key Info']['Exponent']
n = algs.int_repr(cert['Public Key Info']['Modulus'])
if type(msg) == str:
msg = msg.encode('utf-8')
msg = int.from_bytes(msg, 'big')
elif type(msg) == bytes:
msg = int.from_bytes(msg, 'big')
if msg < n:
return pow(msg, e, n)
else:
raise ValueError('Too long message')
def generateKeyToAbonent(self, length, cert):
k = random.randint(2**(length - 1), 2**length)
self.__generated_keys.append(
{'Key': algs.hex_repr(k, length), 'To': cert})
e = cert['Public Key Info']['Exponent']
n = algs.int_repr(cert['Public Key Info']['Modulus'])
l = cert['Public Key Info']['Modulus Length']
k1 = self.encrypt(k, cert)
s1 = self.encrypt(self.signKey(k, length), cert)
return {
'Key': algs.hex_repr(k1, l),
'Length': length,
'Signature': algs.hex_repr(s1, l)
}
def verifyKey(self, key, signature, cert):
e = cert['Public Key Info']['Exponent']
n = algs.int_repr(cert['Public Key Info']['Modulus'])
return pow(signature, e, n) == key