This is a type in BirthdayCAKE. It describes a PublicKeyID. It's found in the cake.keystuff module.
For documentation purposes, here's the code for a version of the class. Notice how the KeyName is generated from a PublicKey or PrivateKey (aka AsymmetricKey) by serializing the PublicKey version of the key, then generating a hash digest of the serialized version:
1 class KeyName(object):
2 """KeyName(str) -> a keyname, str must be a 32 byte string.
3 KeyName(AsymmetricKey) -> The name of the AsymmetricKey passed in."""
4 __slots__ = ('_name', '__weakref__')
5
6 def __init__(self, nameorkey):
7 super(KeyName, self).__init__(self)
8 if isinstance(nameorkey, KeyName):
9 self._name = nameorkey._name
10 elif isinstance(nameorkey, str):
11 if len(nameorkey) != 32: # 256 bits / 8 bits per byte = 32 bytes
12 raise TypeError('A string must be exactly 32 characters long '
13 'to be converted to a %s' % KeyName)
14 else:
15 self._name = intern(nameorkey)
16 elif isinstance(nameorkey, _pubkey.AsymmetricKey):
17 if isinstance(nameorkey, _pubkey.PrivateKey):
18 nameorkey = nameorkey.publicKey()
19 if not isinstance(nameorkey, _pubkey.PublicKey):
20 raise TypeError("Passed in key appears to be neither a %s, "
21 "nor a %s" % (_pubkey.PrivateKey,
22 _pubkey.PublicKey))
23 self._name = intern(_shad_256(serializeKey(nameorkey)).digest())
24 else:
25 raise TypeError("nameorkey must be a string or %s"
26 % _pubkey.AsymmetricKey)
27 def __repr__(self):
28 return '<%s.%s %s>' % \
(KeyName.__module__, KeyName.__name__, self.printableName())
29 def __hash__(self):
30 return hash(self._name)
31 def __cmp__(self, other):
32 return cmp(self._name, other._name)
33 def rawName(self):
34 """The raw 32 byte string containing a key's name."""
35 return self._name
36 def printableName(self):
37 """The human readable, base32 representation of a key's name."""
38 return _b2a32(self._name)