demo.py

from Crypto.Cipher import AES
from Crypto.Protocol.SecretSharing import Shamir
from Crypto.Random import get_random_bytes
from Crypto.Util.Padding import unpad
from base64 import b64decode


def decrypt(ciphertext_iv_hex: str, key: bytes):
    """
    Decrypts data encrypted using Web Crypto API with AES-GCM in Python.

    Args:
        ciphertext_iv_hex (str): Encrypted data as hex string, in format "IV.CIPHERTEXT".
        key (bytes): The decryption key as a byte array.

    Returns:
        str: The decrypted plaintext message.
    """

    try:
        # Split IV and ciphertext from hex string
        iv_hex, ciphertext_hex = ciphertext_iv_hex.split(".")

        iv_bytes = bytes.fromhex(iv_hex)
        # print([b for b in iv_bytes])
        ciphertext_bytes = bytes.fromhex(ciphertext_hex)

        # print([b for b in ciphertext_bytes])

        # Create AES-GCM cipher object with 128-bit tag (for compatibility with Web Crypto)
        cipher = AES.new(key, AES.MODE_CBC, iv=iv_bytes)

        # Decrypt the ciphertext (assuming authentication is handled elsewhere)
        decrypted_bytes = cipher.decrypt(ciphertext_bytes)
        # decrypted_text = unpad(decrypted_bytes, AES.block_size)
        # print("Decrypted ggg:", decrypted_text)
        # cb = [b for b in decrypted_bytes]
        print("Decrypted bytes:", decrypted_bytes.replace(b"\x05", b""))
        decrypted_text = decrypted_bytes.decode("utf-8")  # Assuming UTF-8 encoding

        return decrypted_text

    except ValueError as e:
        print("Decryption error:", e)
        return None  # Return None on decryption failure


# Example usage
key = b"YourSecretKey1234"[:16]  # Keep this key secure!
encrypted_data = "714fd62d80c40154f87d1d174b1d01bf.ca73441f070a344512f85474372e7329ec01722a4a28699218f9bcd13bc81c3d87c80e4b81859f39df70917b54fc6df38bb222d749e5d20c5e1687dbc20956fb"  # Get this from JavaScript
decrypted_text = decrypt(encrypted_data, key)
print("Decrypted message:", decrypted_text)
print("http://localhost:3000/uploads/photo_2024-03-19_01-44-38.jpg".encode())