def f4(self, rand=None):
"""Calculate integrity key.
rand - str or int, if None, use the stored value
return IK as 16B str"""
self._check_rand(rand)
arg = rot(self.temp ^ self.OPc, self.R[4]) ^ self.C[4]
out4 = s2int(self.Ek.encrypt(int2s(arg, 128))) ^ self.OPc
return int2s(out4, 128)
def f3(self, rand=None):
"""Calculate confidentiality key.
rand - str or int, if None, use the stored value
return CK as 16B str"""
self._check_rand(rand)
arg = rot(self.temp ^ self.OPc, self.R[3]) ^ self.C[3]
out3 = s2int(self.Ek.encrypt(int2s(arg, 128))) ^ self.OPc
return int2s(out3, 128)
def f2(self, rand=None):
"""Calculate authentication response.
rand - str or int, if None, use the stored value
return RES as 8B str"""
self._check_rand(rand)
arg = rot(self.temp ^ self.OPc, self.R[2]) ^ self.C[2]
out2 = s2int(self.Ek.encrypt(int2s(arg, 128))) ^ self.OPc
out2s = int2s(out2, 128)
return out2s[8:]
def _check_rand(self, rand):
"""Check provided rand and calculate temp. Use stored values if None"""
if self.rand is None or rand is not None:
self.rand = s2int(randomBytes(16)) if rand is None else \
self._check_int(rand, "RAND", 128)
temp = self.Ek.encrypt(int2s(self.rand ^ self.OPc, 128))
self.temp = s2int(temp)
def _check_str(self, param, label, bitlen=128):
"""Convert param to int and check its value"""
if isinstance(param, int) or isinstance(param, long):
param = int2s(param, bitlen)
assert isinstance(param, str) and 8*len(param) == bitlen, \
"Wrong " + label
return param
def f5s(self, rand=None):
"""Calculate anonimity keys for resync.
rand - str or int, if None, use the stored value
return AK as 48b integer"""
self._check_rand(rand)
arg = rot(self.temp ^ self.OPc, self.R[5]) ^ self.C[5]
out5 = s2int(self.Ek.encrypt(int2s(arg, 128))) ^ self.OPc
return out5 >> 80
def f5(self, rand=None):
"""Calculate anonimity keys for authentication.
rand - str or int, if None, use the stored value
return AK as 48b integer"""
self._check_rand(rand)
arg = rot(self.temp ^ self.OPc, self.R[2]) ^ self.C[2]
out2 = s2int(self.Ek.encrypt(int2s(arg, 128))) ^ self.OPc
return out2 >> 80
def f1(self, rand=None, sqn=None, amf=None):
"""Calculate network & resync authentication code.
rand, sqn, amf - str or int, if None, use the stored value
return (MAC-A, MAC-S) as two 8B str"""
self._check_rand(rand)
if sqn is None:
assert self.sqn is not None, "SQN not stored"
else:
self.sqn = self._check_int(sqn, "SQN", 48)
if amf is None:
assert self.amf is not None, "AMF not stored"
else:
self.amf = self._check_int(amf, "AMF", 16)
in1 = (self.sqn << 16) | self.amf
in1 |= in1 << 64
arg = self.temp ^ rot(in1 ^ self.OPc, self.R[1]) ^ self.C[1]
out1 = s2int(self.Ek.encrypt(int2s(arg, 128))) ^ self.OPc
out1s = int2s(out1, 128)
return out1s[:8], out1s[8:]
def bytestr(self):
""" Get byte string representation of TLV, depending on type. """
# BER, COMPREH: length as in ISO 8825-1 aka X.690
# COMPACT: length 00-FE or FF xx yy
tags = int2s(self.tag)
l = len(self.value)
if self.typ == TLV.COMPACT:
if l < 0xFF:
lens = chr(l)
else:
lens = '\xFF' + pack(">H", l)
else:
lens = derLen(l)
return tags + lens + self.value
def bytestr(self):
""" Get byte string representation of TLV, depending on type. """
# BER, COMPREH: length as in ISO 8825-1 aka X.690
# COMPACT: length 00-FE or FF xx yy
tags = int2s(self.tag)
l = len(self.value)
if self.typ == TLV.COMPACT:
if l < 0xFF:
lens = chr(l)
else:
lens = "\xFF" + pack(">H", l)
else:
lens = derLen(l)
return tags + lens + self.value