xycrypto 0.4

A friendly cryptographic primitives library.

xycrypto

Ciphers

The xycrypto provides simple and elegant interfaces for ciphers.

The cryptography components for ciphers we support:

• Available stream cipher: ARC4, ChaCha20.
• Available block cipher: AES, TripleDES.
• Available mode: ECB, CBC, OFB, CFB, CTR.
• Available padding: PKCS7, ANSIX923, ISO10126.

Usage

Firstly, you should import the cipher class from the package xycrypto.ciphers. The cipher class follows the following naming conventions:

• For stream cipher, <cipher_name>.
• For block cipher, <cipher_name>_<mode>.

>>> from xycrypto.ciphers import AES_CBC

Secondly, you should create the instance of the cipher class. In this case, you should provide some arguments:

• key for all ciphers.
• iv for block cipher in ECB, CBC, OFB, CFB mode.
• nonce for block cipher in CTR mode.
• padding for block cipher in ECB, CBC mode.

# The len(key) is 16 bytes for AES-128, you can use 32 bytes key for AES-256.
>>> key = b'0123456789abcdef'
# Note len(iv) should be equal to AES_CBC.block_size.
>>> iv = b'0123456789abcdef'
# We use PKCS7 padding.
>>> cipher = AES_CBC(key, iv=iv, padding='PKCS7')

Finally, call encrypt or decrypt method to encrypt or decrypt data respectively.

>>> plaintext = b'Welcome to xycrypto!'
>>> ciphertext = cipher.encrypt(plaintext) 
>>> ciphertext
b'3\x0f\xad\xa6\x17\xc4}\xb9\t\x17\xf8\xae\xbb\xa2t\xb9o\xf2\xf6\x16\t\x0803\xaci\x0c\x19q\x9d\xa3O'
>>> cipher.decrypt(ciphertext)
b'Welcome to xycrypto!'

Example

>>> from xycrypto.ciphers import AES_CBC

# The len(key) is 16 bytes for AES-128, you can use 32 bytes key for AES-256.
>>> key = b'0123456789abcdef'
# Note len(iv) should be equal to AES_CBC.block_size.
>>> iv = b'0123456789abcdef'
# We use PKCS7 padding.
>>> cipher = AES_CBC(key, iv=iv, padding='PKCS7')

>>> plaintext = b'Welcome to xycrypto!'
>>> ciphertext = cipher.encrypt(plaintext) 
>>> ciphertext
b'3\x0f\xad\xa6\x17\xc4}\xb9\t\x17\xf8\xae\xbb\xa2t\xb9o\xf2\xf6\x16\t\x0803\xaci\x0c\x19q\x9d\xa3O'
>>> cipher.decrypt(ciphertext)
b'Welcome to xycrypto!'