diff -r 000000000000 -r ae805ac0140d python-2.5.2/win32/Lib/hmac.py --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/python-2.5.2/win32/Lib/hmac.py Fri Apr 03 17:19:34 2009 +0100 @@ -0,0 +1,121 @@ +"""HMAC (Keyed-Hashing for Message Authentication) Python module. + +Implements the HMAC algorithm as described by RFC 2104. +""" + +def _strxor(s1, s2): + """Utility method. XOR the two strings s1 and s2 (must have same length). + """ + return "".join(map(lambda x, y: chr(ord(x) ^ ord(y)), s1, s2)) + +# The size of the digests returned by HMAC depends on the underlying +# hashing module used. +digest_size = None + +# A unique object passed by HMAC.copy() to the HMAC constructor, in order +# that the latter return very quickly. HMAC("") in contrast is quite +# expensive. +_secret_backdoor_key = [] + +class HMAC: + """RFC2104 HMAC class. + + This supports the API for Cryptographic Hash Functions (PEP 247). + """ + + def __init__(self, key, msg = None, digestmod = None): + """Create a new HMAC object. + + key: key for the keyed hash object. + msg: Initial input for the hash, if provided. + digestmod: A module supporting PEP 247. *OR* + A hashlib constructor returning a new hash object. + Defaults to hashlib.md5. + """ + + if key is _secret_backdoor_key: # cheap + return + + if digestmod is None: + import hashlib + digestmod = hashlib.md5 + + if callable(digestmod): + self.digest_cons = digestmod + else: + self.digest_cons = lambda d='': digestmod.new(d) + + self.outer = self.digest_cons() + self.inner = self.digest_cons() + self.digest_size = self.inner.digest_size + + if hasattr(self.inner, 'block_size'): + blocksize = self.inner.block_size + if blocksize < 16: + # Very low blocksize, most likely a legacy value like + # Lib/sha.py and Lib/md5.py have. + blocksize = 64 + else: + blocksize = 64 + + ipad = "\x36" * blocksize + opad = "\x5C" * blocksize + + if len(key) > blocksize: + key = self.digest_cons(key).digest() + + key = key + chr(0) * (blocksize - len(key)) + self.outer.update(_strxor(key, opad)) + self.inner.update(_strxor(key, ipad)) + if msg is not None: + self.update(msg) + +## def clear(self): +## raise NotImplementedError, "clear() method not available in HMAC." + + def update(self, msg): + """Update this hashing object with the string msg. + """ + self.inner.update(msg) + + def copy(self): + """Return a separate copy of this hashing object. + + An update to this copy won't affect the original object. + """ + other = HMAC(_secret_backdoor_key) + other.digest_cons = self.digest_cons + other.digest_size = self.digest_size + other.inner = self.inner.copy() + other.outer = self.outer.copy() + return other + + def digest(self): + """Return the hash value of this hashing object. + + This returns a string containing 8-bit data. The object is + not altered in any way by this function; you can continue + updating the object after calling this function. + """ + h = self.outer.copy() + h.update(self.inner.digest()) + return h.digest() + + def hexdigest(self): + """Like digest(), but returns a string of hexadecimal digits instead. + """ + return "".join([hex(ord(x))[2:].zfill(2) + for x in tuple(self.digest())]) + +def new(key, msg = None, digestmod = None): + """Create a new hashing object and return it. + + key: The starting key for the hash. + msg: if available, will immediately be hashed into the object's starting + state. + + You can now feed arbitrary strings into the object using its update() + method, and can ask for the hash value at any time by calling its digest() + method. + """ + return HMAC(key, msg, digestmod)