ó õùPc @s4dZddddddddd d g Zd Zd S( sHashing algorithms Hash functions take arbitrary binary strings as input, and produce a random-like output of fixed size that is dependent on the input; it should be practically infeasible to derive the original input data given only the hash function's output. In other words, the hash function is *one-way*. It should also not be practically feasible to find a second piece of data (a *second pre-image*) whose hash is the same as the original message (*weak collision resistance*). Finally, it should not be feasible to find two arbitrary messages with the same hash (*strong collision resistance*). The output of the hash function is called the *digest* of the input message. In general, the security of a hash function is related to the length of the digest. If the digest is *n* bits long, its security level is roughly comparable to the the one offered by an *n/2* bit encryption algorithm. Hash functions can be used simply as a integrity check, or, in association with a public-key algorithm, can be used to implement digital signatures. The hashing modules here all support the interface described in `PEP 247`_ , "API for Cryptographic Hash Functions". .. _`PEP 247` : http://www.python.org/dev/peps/pep-0247/ :undocumented: _MD2, _MD4, _RIPEMD160, _SHA224, _SHA256, _SHA384, _SHA512 tHMACtMD2tMD4tMD5tRIPEMDtSHAtSHA224tSHA256tSHA384tSHA512s$Id$N(t__doc__t__all__t __revision__(((s/..\python\site-packages\Crypto\Hash\__init__.pyt2s