Na}{

File Content: `DES.cpython-37.pyc`

B

����Bd\R3������������������@���sb���d�Z�dZddlmZ�ddlmZ�G�dd��dej�Zdd��Zd	Zd
Z	dZ
dZd
ZdZ
dZdZdZdS�)a���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)

.. __: http://en.wikipedia.org/wiki/Data_Encryption_Standard
.. _NIST: http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf

:undocumented: __revision__, __package__
z$Id$�����)�	blockalgo)�_DESc���������������@���s���e�Zd�ZdZdd��ZdS�)�	DESCipherzDES cipher objectc�������������O���s���t�jj|�t|f|�|��dS�)zUInitialize a DES cipher object
        
        See also `new()` at the module level.N)r����	BlockAlgo�__init__r���)�self�key�args�kwargs��r����D/opt/alt/python37/lib64/python3.7/site-packages/Crypto/Cipher/DES.pyr���;���s����zDESCipher.__init__N)�__name__�
__module__�__qualname__�__doc__r���r���r���r���r���r���8���s���r���c�������������O���s���t�|�f|�|�S�)am��Create a new DES cipher

    :Parameters:
      key : byte string
        The secret key to use in the symmetric cipher.
        It must be 8 byte long. The parity bits will be ignored.
    :Keywords:
      mode : a *MODE_** constant
        The chaining mode to use for encryption or decryption.
        Default is `MODE_ECB`.
      IV : byte string
        The initialization vector to use for encryption or decryption.
        
        It is ignored for `MODE_ECB` and `MODE_CTR`.

        For `MODE_OPENPGP`, IV must be `block_size` bytes long for encryption
        and `block_size` +2 bytes for decryption (in the latter case, it is
        actually the *encrypted* IV which was prefixed to the ciphertext).
        It is mandatory.
       
        For all other modes, it must be `block_size` bytes longs. It is optional and
        when not present it will be given a default value of all zeroes.
      counter : callable
        (*Only* `MODE_CTR`). A stateful function that returns the next
        *counter block*, which is a byte string of `block_size` bytes.
        For better performance, use `Crypto.Util.Counter`.
      segment_size : integer
        (*Only* `MODE_CFB`).The number of bits the plaintext and ciphertext
        are segmented in.
        It must be a multiple of 8. If 0 or not specified, it will be assumed to be 8.

    :Return: an `DESCipher` object
    )r���)r���r	���r
���r���r���r����newA���s����"r�����������������������������������N)r���Z__revision__Z
Crypto.Cipherr���r���r���r���r���ZMODE_ECBZMODE_CBCZMODE_CFBZMODE_PGPZMODE_OFBZMODE_CTRZMODE_OPENPGPZ
block_sizeZkey_sizer���r���r���r����<module>1���s���	%

Name	Size	Permission
AES.cpython-37.opt-1.pyc	3252 bytes	0644
AES.cpython-37.pyc	3252 bytes	0644
ARC2.cpython-37.opt-1.pyc	3948 bytes	0644
ARC2.cpython-37.pyc	3948 bytes	0644
ARC4.cpython-37.opt-1.pyc	3639 bytes	0644
ARC4.cpython-37.pyc	3639 bytes	0644
Blowfish.cpython-37.opt-1.pyc	3486 bytes	0644
Blowfish.cpython-37.pyc	3486 bytes	0644
CAST.cpython-37.opt-1.pyc	3534 bytes	0644
CAST.cpython-37.pyc	3534 bytes	0644
DES.cpython-37.opt-1.pyc	3436 bytes	0644
DES.cpython-37.pyc	3436 bytes	0644
DES3.cpython-37.opt-1.pyc	4164 bytes	0644
DES3.cpython-37.pyc	4164 bytes	0644
PKCS1_OAEP.cpython-37.opt-1.pyc	7569 bytes	0644
PKCS1_OAEP.cpython-37.pyc	7569 bytes	0644
PKCS1_v1_5.cpython-37.opt-1.pyc	8446 bytes	0644
PKCS1_v1_5.cpython-37.pyc	8446 bytes	0644
XOR.cpython-37.opt-1.pyc	2107 bytes	0644
XOR.cpython-37.pyc	2107 bytes	0644
__init__.cpython-37.opt-1.pyc	2586 bytes	0644
__init__.cpython-37.pyc	2586 bytes	0644
blockalgo.cpython-37.opt-1.pyc	5451 bytes	0644
blockalgo.cpython-37.pyc	5451 bytes	0644

File Content: DES.cpython-37.pyc

File Content: `DES.cpython-37.pyc`