Decrypt TrainerRoad Course

decrypt.py

#!/usr/bin/env python


def decode_buf(ciphertext):
    from Crypto.Protocol.KDF import PBKDF2
    (KEY_SIZE, IV_SIZE) = (256 // 8, 128 // 8)
    key_iv = PBKDF2("4ZpHznL4ELiAiZEXpAloFPA7sO4NqVLLd8qavZ8D", b"vxZIH70vLr9i8pymHC0U", dkLen=KEY_SIZE + IV_SIZE)
    (key, iv) = (key_iv[:KEY_SIZE], key_iv[KEY_SIZE:])

    from Crypto.Cipher import AES
    cipher = AES.new(key, mode=AES.MODE_CBC, IV=iv)
    plaintext = cipher.decrypt(ciphertext[4:])
    plaintext = plaintext[:-plaintext[-1]]

    import gzip
    return gzip.decompress(plaintext)


def decode_file(path):
    data = decode_buf(open(path, 'rb').read())
    open(path + '.dec', 'wb').write(data)


def main():
    from sys import argv
    for i in argv[1:]:
        print(i)
        decode_file(i)


if __name__ == '__main__':
    main()