| 1 | # Copyright (C) 2010 Nominum, Inc.
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| 2 | #
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| 3 | # Permission to use, copy, modify, and distribute this software and its
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| 4 | # documentation for any purpose with or without fee is hereby granted,
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| 5 | # provided that the above copyright notice and this permission notice
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| 6 | # appear in all copies.
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| 7 | #
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| 8 | # THE SOFTWARE IS PROVIDED "AS IS" AND NOMINUM DISCLAIMS ALL WARRANTIES
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| 9 | # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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| 10 | # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NOMINUM BE LIABLE FOR
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| 11 | # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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| 12 | # WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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| 13 | # ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
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| 14 | # OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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| 15 |
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| 16 | """Hashing backwards compatibility wrapper"""
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| 17 |
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| 18 | import sys
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| 19 |
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| 20 | _hashes = None
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| 21 |
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| 22 | def _need_later_python(alg):
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| 23 | def func(*args, **kwargs):
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| 24 | raise NotImplementedError("TSIG algorithm " + alg +
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| 25 | " requires Python 2.5.2 or later")
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| 26 | return func
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| 27 |
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| 28 | def _setup():
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| 29 | global _hashes
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| 30 | _hashes = {}
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| 31 | try:
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| 32 | import hashlib
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| 33 | _hashes['MD5'] = hashlib.md5
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| 34 | _hashes['SHA1'] = hashlib.sha1
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| 35 | _hashes['SHA224'] = hashlib.sha224
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| 36 | _hashes['SHA256'] = hashlib.sha256
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| 37 | if sys.hexversion >= 0x02050200:
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| 38 | _hashes['SHA384'] = hashlib.sha384
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| 39 | _hashes['SHA512'] = hashlib.sha512
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| 40 | else:
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| 41 | _hashes['SHA384'] = _need_later_python('SHA384')
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| 42 | _hashes['SHA512'] = _need_later_python('SHA512')
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| 43 |
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| 44 | if sys.hexversion < 0x02050000:
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| 45 | # hashlib doesn't conform to PEP 247: API for
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| 46 | # Cryptographic Hash Functions, which hmac before python
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| 47 | # 2.5 requires, so add the necessary items.
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| 48 | class HashlibWrapper:
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| 49 | def __init__(self, basehash):
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| 50 | self.basehash = basehash
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| 51 | self.digest_size = self.basehash().digest_size
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| 52 |
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| 53 | def new(self, *args, **kwargs):
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| 54 | return self.basehash(*args, **kwargs)
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| 55 |
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| 56 | for name in _hashes:
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| 57 | _hashes[name] = HashlibWrapper(_hashes[name])
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| 58 |
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| 59 | except ImportError:
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| 60 | import md5, sha
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| 61 | _hashes['MD5'] = md5
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| 62 | _hashes['SHA1'] = sha
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| 63 |
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| 64 | def get(algorithm):
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| 65 | if _hashes is None:
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| 66 | _setup()
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| 67 | return _hashes[algorithm.upper()]
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