From e88db3739daefb65e459845fde880c0c8a7ae31f Mon Sep 17 00:00:00 2001 From: Legrandin Date: Thu, 10 May 2012 19:39:46 +0200 Subject: Added description of what DES is. --- lib/Crypto/Cipher/DES.py | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/lib/Crypto/Cipher/DES.py b/lib/Crypto/Cipher/DES.py index 46862d7..24a19b3 100644 --- a/lib/Crypto/Cipher/DES.py +++ b/lib/Crypto/Cipher/DES.py @@ -20,6 +20,20 @@ # =================================================================== """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 bit 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`. + +.. __: http://en.wikipedia.org/wiki/Data_Encryption_Standard +.. _NIST: http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf + + :undocumented: __revision__, __package__ """ @@ -44,7 +58,7 @@ def new(key, *args, **kwargs): :Parameters: key : byte string The secret key to use in the symmetric cipher. - It must be 8 byte long. + 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. -- cgit v1.2.1