TgCrypto

Note

The project is no longer maintained or supported. Thanks for appreciating it.

Note

The implementations of the algorithms presented in this repository are to be considered for educational purposes only.

Fast and Portable Cryptography Extension Library for Pyrogram

TgCrypto is a Cryptography Library written in C as a Python extension. It is designed to be portable, fast, easy to install and use. TgCrypto is intended for Pyrogram and implements the cryptographic algorithms Telegram requires, namely:

• AES-256-IGE - used in MTProto v2.0.
• AES-256-CTR - used for CDN encrypted files.
• AES-256-CBC - used for encrypted passport credentials.

Requirements

• Python 3.7 or higher.

Installation

$ pip3 install -U tgcrypto

API

TgCrypto API consists of these six methods:

def ige256_encrypt(data: bytes, key: bytes, iv: bytes) -> bytes: ...
def ige256_decrypt(data: bytes, key: bytes, iv: bytes) -> bytes: ...

def ctr256_encrypt(data: bytes, key: bytes, iv: bytes, state: bytes) -> bytes: ...
def ctr256_decrypt(data: bytes, key: bytes, iv: bytes, state: bytes) -> bytes: ...

def cbc256_encrypt(data: bytes, key: bytes, iv: bytes) -> bytes: ...
def cbc256_decrypt(data: bytes, key: bytes, iv: bytes) -> bytes: ...

Usage

IGE Mode

Note: Data must be padded to match a multiple of the block size (16 bytes).

import os

import tgcrypto

data = os.urandom(10 * 1024 * 1024 + 7)  # 10 MB of random data + 7 bytes to show padding
key = os.urandom(32)  # Random Key
iv = os.urandom(32)  # Random IV

# Pad with zeroes: -7 % 16 = 9
data += bytes(-len(data) % 16)

ige_encrypted = tgcrypto.ige256_encrypt(data, key, iv)
ige_decrypted = tgcrypto.ige256_decrypt(ige_encrypted, key, iv)

print(data == ige_decrypted)  # True

CTR Mode (single chunk)

import os

import tgcrypto

data = os.urandom(10 * 1024 * 1024)  # 10 MB of random data

key = os.urandom(32)  # Random Key

enc_iv = bytearray(os.urandom(16))  # Random IV
dec_iv = enc_iv.copy()  # Keep a copy for decryption

ctr_encrypted = tgcrypto.ctr256_encrypt(data, key, enc_iv, bytes(1))
ctr_decrypted = tgcrypto.ctr256_decrypt(ctr_encrypted, key, dec_iv, bytes(1))

print(data == ctr_decrypted)  # True

CTR Mode (stream)

import os
from io import BytesIO

import tgcrypto

data = BytesIO(os.urandom(10 * 1024 * 1024))  # 10 MB of random data

key = os.urandom(32)  # Random Key

enc_iv = bytearray(os.urandom(16))  # Random IV
dec_iv = enc_iv.copy()  # Keep a copy for decryption

enc_state = bytes(1)  # Encryption state, starts from 0
dec_state = bytes(1)  # Decryption state, starts from 0

encrypted_data = BytesIO()  # Encrypted data buffer
decrypted_data = BytesIO()  # Decrypted data buffer

while True:
    chunk = data.read(1024)

    if not chunk:
        break

    # Write 1K encrypted bytes into the encrypted data buffer
    encrypted_data.write(tgcrypto.ctr256_encrypt(chunk, key, enc_iv, enc_state))

# Reset position. We need to read it now
encrypted_data.seek(0)

while True:
    chunk = encrypted_data.read(1024)

    if not chunk:
        break

    # Write 1K decrypted bytes into the decrypted data buffer
    decrypted_data.write(tgcrypto.ctr256_decrypt(chunk, key, dec_iv, dec_state))

print(data.getvalue() == decrypted_data.getvalue())  # True

CBC Mode

Note: Data must be padded to match a multiple of the block size (16 bytes).

import os

import tgcrypto

data = os.urandom(10 * 1024 * 1024 + 7)  # 10 MB of random data + 7 bytes to show padding
key = os.urandom(32)  # Random Key

enc_iv = bytearray(os.urandom(16))  # Random IV
dec_iv = enc_iv.copy()  # Keep a copy for decryption

# Pad with zeroes: -7 % 16 = 9
data += bytes(-len(data) % 16)

cbc_encrypted = tgcrypto.cbc256_encrypt(data, key, enc_iv)
cbc_decrypted = tgcrypto.cbc256_decrypt(cbc_encrypted, key, dec_iv)

print(data == cbc_decrypted)  # True

Testing

1. Clone this repository: git clone https://github.com/pyrogram/tgcrypto.
2. Enter the directory: cd tgcrypto.
3. Install tox: pip3 install tox
4. Run tests: tox.

License

LGPLv3+ © 2017-present Dan