mirror of
https://github.com/aljazceru/python-teos.git
synced 2025-12-17 14:14:22 +01:00
60 lines
2.5 KiB
Python
60 lines
2.5 KiB
Python
import re
|
|
from hashlib import sha256
|
|
from binascii import hexlify, unhexlify
|
|
from cryptography.hazmat.primitives.ciphers.aead import AESGCM
|
|
|
|
from apps.cli import logging
|
|
from apps.cli import SUPPORTED_HASH_FUNCTIONS, SUPPORTED_CIPHERS
|
|
|
|
|
|
class Blob:
|
|
def __init__(self, data, cipher, hash_function):
|
|
if type(data) is not str or re.search(r'^[0-9A-Fa-f]+$', data) is None:
|
|
raise ValueError("Non-Hex character found in txid.")
|
|
|
|
self.data = data
|
|
self.cipher = cipher
|
|
self.hash_function = hash_function
|
|
|
|
# FIXME: We only support SHA256 for now
|
|
if self.hash_function.upper() not in SUPPORTED_HASH_FUNCTIONS:
|
|
raise ValueError("Hash function not supported ({}). Supported Hash functions: {}"
|
|
.format(self.hash_function, SUPPORTED_HASH_FUNCTIONS))
|
|
|
|
# FIXME: We only support AES-GCM-128 for now
|
|
if self.cipher.upper() not in SUPPORTED_CIPHERS:
|
|
raise ValueError("Cipher not supported ({}). Supported ciphers: {}".format(self.hash_function,
|
|
SUPPORTED_CIPHERS))
|
|
|
|
def encrypt(self, tx_id):
|
|
if len(tx_id) != 64:
|
|
raise ValueError("txid does not matches the expected size (32-byte / 64 hex chars).")
|
|
|
|
elif re.search(r'^[0-9A-Fa-f]+$', tx_id) is None:
|
|
raise ValueError("Non-Hex character found in txid.")
|
|
|
|
# Transaction to be encrypted
|
|
# FIXME: The blob data should contain more things that just the transaction. Leaving like this for now.
|
|
tx = unhexlify(self.data)
|
|
tx_id = unhexlify(tx_id)
|
|
|
|
# master_key = H(tx_id | tx_id)
|
|
master_key = sha256(tx_id + tx_id).digest()
|
|
|
|
# The 16 MSB of the master key will serve as the AES GCM 128 secret key. The 16 LSB will serve as the IV.
|
|
sk = master_key[:16]
|
|
nonce = master_key[16:]
|
|
|
|
# Encrypt the data
|
|
aesgcm = AESGCM(sk)
|
|
encrypted_blob = aesgcm.encrypt(nonce=nonce, data=tx, associated_data=None)
|
|
encrypted_blob = hexlify(encrypted_blob).decode()
|
|
|
|
logging.info("[Client] creating new blob")
|
|
logging.info("[Client] master key: {}".format(hexlify(master_key).decode()))
|
|
logging.info("[Client] sk: {}".format(hexlify(sk).decode()))
|
|
logging.info("[Client] nonce: {}".format(hexlify(nonce).decode()))
|
|
logging.info("[Client] encrypted_blob: {}".format(encrypted_blob))
|
|
|
|
return encrypted_blob
|