source: trunk/essentials/dev-lang/python/Lib/hmac.py@ 3951

"""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.