def decrypt_query(self, query: bytes):
"""
Decrypts a query received by the server
query - The query to decrypt
"""
# Parse the server key
# Parsre the msg, extract the pubkey and the {IV || payload} from the query
pubkey = query[0:65] # uncompressed pubkey's length is 65 bytes
encrypted = query[65:]
ephemeral_public_key = PublicKey(pubkey)
# Generate the AES key
aes_key = decapsulate(ephemeral_public_key, self.server_sk)
return aes_decrypt(aes_key, encrypted), aes_key
def decrypt(receiver_prvhex: str, msg: bytes) -> bytes:
"""
Decrypt with eth private key
Parameters
----------
receiver_pubhex: str
Receiver's ethereum private key hex string
msg: bytes
Data to decrypt
Returns
-------
bytes
Plain text
"""
pubkey = msg[0:65] # pubkey's length is 65 bytes
encrypted = msg[65:]
sender_public_key = hex2pub(pubkey.hex())
private_key = hex2prv(receiver_prvhex)
aes_key = derive(private_key, sender_public_key)
return aes_decrypt(aes_key, encrypted)
def test_aes(self):
data = self.big_data
key = os.urandom(16)
self.assertEqual(data, aes_decrypt(key, aes_encrypt(key, data)))
def decrypt_shared_secret(aes_key, ciphertext):
encrypted = ciphertext[65:]
return aes_decrypt(aes_key, encrypted)
def decrypt_answer(self, answer: bytes, aes_key: bytes):
return aes_decrypt(aes_key, answer)