Module DES

DES symmetric cipher

DES (Data Encryption Standard) is a symmetric block cipher standardized by NIST . It has a fixed data block size of 8 bytes. Its keys are 64 bits long, even though 8 bits were used for integrity (now they are ignored) and do not contribute to securty.

DES is cryptographically secure, but its key length is too short by nowadays standards and it could be brute forced with some effort.

DES should not be used for new designs. Use AES.

As an example, encryption can be done as follows:

>>> from Crypto.Cipher import DES3
>>> from Crypto import Random
>>>
>>> key = b'Sixteen byte key'
>>> iv = Random.new().read(DES3.block_size)
>>> cipher = DES3.new(key, DES3.MODE_OFB, iv)
>>> plaintext = b'sona si latine loqueris '
>>> msg = iv + cipher.encrypt(plaintext)