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"""Hashing algorithms
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Hash functions take arbitrary strings as input, and produce an output
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of fixed size that is dependent on the input; it should never be
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possible to derive the input data given only the hash function's
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output. Hash functions can be used simply as a checksum, or, in
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Hash functions take arbitrary binary strings as input, and produce a random-like output
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of fixed size that is dependent on the input; it should be practically infeasible
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to derive the original input data given only the hash function's
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output. In other words, the hash function is *one-way*.
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It should also not be practically feasible to find a second piece of data
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(a *second pre-image*) whose hash is the same as the original message
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(*weak collision resistance*).
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Finally, it should not be feasible to find two arbitrary messages with the
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same hash (*strong collision resistance*).
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The output of the hash function is called the *digest* of the input message.
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In general, the security of a hash function is related to the length of the
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digest. If the digest is *n* bits long, its security level is roughly comparable
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to the the one offered by an *n/2* bit encryption algorithm.
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Hash functions can be used simply as a integrity check, or, in
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association with a public-key algorithm, can be used to implement
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digital signatures.
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The hashing modules here all support the interface described in PEP
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247, "API for Cryptographic Hash Functions".
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RFC 2104. Keyed-Hashing for Message Authentication.
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RFC1319. Rivest's Message Digest algorithm, with a 128 bit digest. This algorithm is both slow and insecure.
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RFC1320. Rivest's Message Digest algorithm, with a 128 bit digest. This algorithm is insecure.
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RFC1321. Rivest's Message Digest algorithm, with a 128 bit digest. This algorithm is insecure.
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RACE Integrity Primitives Evaluation Message Digest algorithm, with a 160 bit digest.
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Secure Hash Algorithm 1 (SHA-1), with a 160 bit digest. Published in FIPS PUB 180-1/2/3.
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Secure Hash Algorithm 2 (SHA-2 family), with a 224 bit digest. Published in FIPS PUB 180-2/3.
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Secure Hash Algorithm 2 (SHA-2 family), with a 256 bit digest. Published in FIPS PUB 180-2/3.
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Secure Hash Algorithm 2 (SHA-2 family), with a 384 bit digest. Published in FIPS PUB 180-2/3.
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Secure Hash Algorithm 2 (SHA-2 family), with a 512 bit digest. Published in FIPS PUB 180-2/3.
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The hashing modules here all support the interface described in `PEP
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247`_ , "API for Cryptographic Hash Functions".
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.. _`PEP 247` : http://www.python.org/dev/peps/pep-0247/
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:undocumented: _MD2, _MD4, _RIPEMD160, _SHA224, _SHA256, _SHA384, _SHA512
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__all__ = ['HMAC', 'MD2', 'MD4', 'MD5', 'RIPEMD', 'SHA',
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lib/Crypto/Hash/__init__.py
