def encode(self, value):
""" Identity encoding (str->str) with signature """
if self._signkey:
from Crypto.Hash import HMAC
value = _sharedance.escape(
HMAC.new(self._signkey, value).digest()[:8]
) + value
return value
def decode(self, value):
""" Identity decoding (str->str) with integrity checking """
if self._signkey:
sign, value = value[:11], value[11:] # 11 = 8 * 4/3 - padding
from Crypto.Hash import HMAC
if _sharedance.escape(
HMAC.new(self._signkey, value).digest()[:8]) != sign:
raise ValueError()
return value
def _gensid(self):
""" Generate a random session ID """
numbytes, rest = divmod(self._SIDLEN * 3, 4)
numbytes += int(bool(rest))
return _sharedance.escape(_os.urandom(numbytes))[:self._SIDLEN]
