OTR plugin for Gajim 1.0+
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# Copyright 2011-2012 Kjell Braden <afflux@pentabarf.de>
#
# This file is part of the python-potr library.
#
# python-potr is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# any later version.
#
# python-potr is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this library. If not, see <http://www.gnu.org/licenses/>.
# some python3 compatibilty
from __future__ import unicode_literals
import logging
import struct
from potr.compatcrypto import SHA256, SHA1, SHA1HMAC, SHA256HMAC, \
Counter, AESCTR, PK, getrandbits, randrange
from potr.utils import bytes_to_long, long_to_bytes, pack_mpi, read_mpi
from potr import proto
logger = logging.getLogger(__name__)
STATE_NONE = 0
STATE_AWAITING_DHKEY = 1
STATE_AWAITING_REVEALSIG = 2
STATE_AWAITING_SIG = 4
STATE_V1_SETUP = 5
DH_MODULUS = 2410312426921032588552076022197566074856950548502459942654116941958108831682612228890093858261341614673227141477904012196503648957050582631942730706805009223062734745341073406696246014589361659774041027169249453200378729434170325843778659198143763193776859869524088940195577346119843545301547043747207749969763750084308926339295559968882457872412993810129130294592999947926365264059284647209730384947211681434464714438488520940127459844288859336526896320919633919
DH_MODULUS_2 = DH_MODULUS-2
DH_GENERATOR = 2
DH_BITS = 1536
DH_MAX = 2**DH_BITS
SM_ORDER = (DH_MODULUS - 1) // 2
def check_group(n):
return 2 <= n <= DH_MODULUS_2
def check_exp(n):
return 1 <= n < SM_ORDER
def SHA256HMAC160(key, data):
return SHA256HMAC(key, data)[:20]
class DH(object):
@classmethod
def set_params(cls, prime, gen):
cls.prime = prime
cls.gen = gen
def __init__(self):
self.priv = randrange(2, 2**320)
self.pub = pow(self.gen, self.priv, self.prime)
DH.set_params(DH_MODULUS, DH_GENERATOR)
class DHSession(object):
def __init__(self, sendenc, sendmac, rcvenc, rcvmac):
self.sendenc = sendenc
self.sendmac = sendmac
self.rcvenc = rcvenc
self.rcvmac = rcvmac
self.sendctr = Counter(0)
self.rcvctr = Counter(0)
self.sendmacused = False
self.rcvmacused = False
def __repr__(self):
return '<{cls}(send={s!r},rcv={r!r})>' \
.format(cls=self.__class__.__name__,
s=self.sendmac, r=self.rcvmac)
@classmethod
def create(cls, dh, y):
s = pow(y, dh.priv, DH_MODULUS)
sb = pack_mpi(s)
if dh.pub > y:
sendbyte = b'\1'
rcvbyte = b'\2'
else:
sendbyte = b'\2'
rcvbyte = b'\1'
sendenc = SHA1(sendbyte + sb)[:16]
sendmac = SHA1(sendenc)
rcvenc = SHA1(rcvbyte + sb)[:16]
rcvmac = SHA1(rcvenc)
return cls(sendenc, sendmac, rcvenc, rcvmac)
class CryptEngine(object):
def __init__(self, ctx):
self.ctx = ctx
self.ake = None
self.sessionId = None
self.sessionIdHalf = False
self.theirKeyid = 0
self.theirY = None
self.theirOldY = None
self.ourOldDHKey = None
self.ourDHKey = None
self.ourKeyid = 0
self.sessionkeys = {0:{0:None, 1:None}, 1:{0:None, 1:None}}
self.theirPubkey = None
self.savedMacKeys = []
self.smp = None
self.extraKey = None
def revealMacs(self, ours=True):
if ours:
dhs = self.sessionkeys[1].values()
else:
dhs = ( v[1] for v in self.sessionkeys.values() )
for v in dhs:
if v is not None:
if v.rcvmacused:
self.savedMacKeys.append(v.rcvmac)
if v.sendmacused:
self.savedMacKeys.append(v.sendmac)
def rotateDHKeys(self):
self.revealMacs(ours=True)
self.ourOldDHKey = self.ourDHKey
self.sessionkeys[1] = self.sessionkeys[0].copy()
self.ourDHKey = DH()
self.ourKeyid += 1
self.sessionkeys[0][0] = None if self.theirY is None else \
DHSession.create(self.ourDHKey, self.theirY)
self.sessionkeys[0][1] = None if self.theirOldY is None else \
DHSession.create(self.ourDHKey, self.theirOldY)
logger.debug('{0}: Refreshing ourkey to {1} {2}'.format(
self.ctx.user.name, self.ourKeyid, self.sessionkeys))
def rotateYKeys(self, new_y):
self.theirOldY = self.theirY
self.revealMacs(ours=False)
self.sessionkeys[0][1] = self.sessionkeys[0][0]
self.sessionkeys[1][1] = self.sessionkeys[1][0]
self.theirY = new_y
self.theirKeyid += 1
self.sessionkeys[0][0] = DHSession.create(self.ourDHKey, self.theirY)
self.sessionkeys[1][0] = DHSession.create(self.ourOldDHKey, self.theirY)
logger.debug('{0}: Refreshing theirkey to {1} {2}'.format(
self.ctx.user.name, self.theirKeyid, self.sessionkeys))
def handleDataMessage(self, msg):
if self.saneKeyIds(msg) is False:
raise InvalidParameterError
sesskey = self.sessionkeys[self.ourKeyid - msg.rkeyid] \
[self.theirKeyid - msg.skeyid]
logger.debug('sesskeys: {0!r}, our={1}, r={2}, their={3}, s={4}' \
.format(self.sessionkeys, self.ourKeyid, msg.rkeyid,
self.theirKeyid, msg.skeyid))
if msg.mac != SHA1HMAC(sesskey.rcvmac, msg.getMacedData()):
logger.error('HMACs don\'t match')
raise InvalidParameterError
sesskey.rcvmacused = True
newCtrPrefix = bytes_to_long(msg.ctr)
if newCtrPrefix <= sesskey.rcvctr.prefix:
logger.error('CTR must increase (old %r, new %r)',
sesskey.rcvctr.prefix, newCtrPrefix)
raise InvalidParameterError
sesskey.rcvctr.prefix = newCtrPrefix
logger.debug('handle: enc={0!r} mac={1!r} ctr={2!r}' \
.format(sesskey.rcvenc, sesskey.rcvmac, sesskey.rcvctr))
plaintextData = AESCTR(sesskey.rcvenc, sesskey.rcvctr) \
.decrypt(msg.encmsg)
if b'\0' in plaintextData:
plaintext, tlvData = plaintextData.split(b'\0', 1)
tlvs = proto.TLV.parse(tlvData)
else:
plaintext = plaintextData
tlvs = []
if msg.rkeyid == self.ourKeyid:
self.rotateDHKeys()
if msg.skeyid == self.theirKeyid:
self.rotateYKeys(bytes_to_long(msg.dhy))
return plaintext, tlvs
def smpSecret(self, secret, question=None, appdata=None):
if self.smp is None:
logger.debug('Creating SMPHandler')
self.smp = SMPHandler(self)
self.smp.gotSecret(secret, question=question, appdata=appdata)
def smpHandle(self, tlv, appdata=None):
if self.smp is None:
logger.debug('Creating SMPHandler')
self.smp = SMPHandler(self)
self.smp.handle(tlv, appdata=appdata)
def smpAbort(self, appdata=None):
if self.smp is None:
logger.debug('Creating SMPHandler')
self.smp = SMPHandler(self)
self.smp.abort(appdata=appdata)
def createDataMessage(self, message, flags=0, tlvs=None):
# check MSGSTATE
if self.theirKeyid == 0:
raise InvalidParameterError
if tlvs is None:
tlvs = []
sess = self.sessionkeys[1][0]
sess.sendctr.inc()
logger.debug('create: enc={0!r} mac={1!r} ctr={2!r}' \
.format(sess.sendenc, sess.sendmac, sess.sendctr))
# plaintext + TLVS
plainBuf = message + b'\0' + b''.join([ bytes(t) for t in tlvs])
encmsg = AESCTR(sess.sendenc, sess.sendctr).encrypt(plainBuf)
msg = proto.DataMessage(flags, self.ourKeyid-1, self.theirKeyid,
long_to_bytes(self.ourDHKey.pub), sess.sendctr.byteprefix(),
encmsg, b'', b''.join(self.savedMacKeys))
self.savedMacKeys = []
msg.mac = SHA1HMAC(sess.sendmac, msg.getMacedData())
return msg
def saneKeyIds(self, msg):
anyzero = self.theirKeyid == 0 or msg.skeyid == 0 or msg.rkeyid == 0
if anyzero or (msg.skeyid != self.theirKeyid and \
msg.skeyid != self.theirKeyid - 1) or \
(msg.rkeyid != self.ourKeyid and msg.rkeyid != self.ourKeyid - 1):
return False
if self.theirOldY is None and msg.skeyid == self.theirKeyid - 1:
return False
return True
def startAKE(self, appdata=None):
self.ake = AuthKeyExchange(self.ctx.user.getPrivkey(), self.goEncrypted)
outMsg = self.ake.startAKE()
self.ctx.sendInternal(outMsg, appdata=appdata)
def handleAKE(self, inMsg, appdata=None):
outMsg = None
if not self.ctx.getPolicy('ALLOW_V2'):
return
if isinstance(inMsg, proto.DHCommit):
if self.ake is None or self.ake.state != STATE_AWAITING_REVEALSIG:
self.ake = AuthKeyExchange(self.ctx.user.getPrivkey(),
self.goEncrypted)
outMsg = self.ake.handleDHCommit(inMsg)
elif isinstance(inMsg, proto.DHKey):
if self.ake is None:
return # ignore
outMsg = self.ake.handleDHKey(inMsg)
elif isinstance(inMsg, proto.RevealSig):
if self.ake is None:
return # ignore
outMsg = self.ake.handleRevealSig(inMsg)
elif isinstance(inMsg, proto.Signature):
if self.ake is None:
return # ignore
self.ake.handleSignature(inMsg)
if outMsg is not None:
self.ctx.sendInternal(outMsg, appdata=appdata)
def goEncrypted(self, ake):
if ake.dh.pub == ake.gy:
logger.warning('We are receiving our own messages')
raise InvalidParameterError
# TODO handle new fingerprint
self.theirPubkey = ake.theirPubkey
self.sessionId = ake.sessionId
self.sessionIdHalf = ake.sessionIdHalf
self.theirKeyid = ake.theirKeyid
self.ourKeyid = ake.ourKeyid
self.theirY = ake.gy
self.theirOldY = None
self.extraKey = ake.extraKey
if self.ourKeyid != ake.ourKeyid + 1 or self.ourOldDHKey != ake.dh.pub:
self.ourDHKey = ake.dh
self.sessionkeys[0][0] = DHSession.create(self.ourDHKey, self.theirY)
self.rotateDHKeys()
# we don't need the AKE anymore, free the reference
self.ake = None
self.ctx._wentEncrypted()
logger.info('went encrypted with {0}'.format(self.theirPubkey))
def finished(self):
self.smp = None
class AuthKeyExchange(object):
def __init__(self, privkey, onSuccess):
self.privkey = privkey
self.state = STATE_NONE
self.r = None
self.encgx = None
self.hashgx = None
self.ourKeyid = 1
self.theirPubkey = None
self.theirKeyid = 1
self.enc_c = None
self.enc_cp = None
self.mac_m1 = None
self.mac_m1p = None
self.mac_m2 = None
self.mac_m2p = None
self.sessionId = None
self.sessionIdHalf = False
self.dh = DH()
self.onSuccess = onSuccess
self.gy = None
self.extraKey = None
self.lastmsg = None
def startAKE(self):
self.r = long_to_bytes(getrandbits(128), 16)
gxmpi = pack_mpi(self.dh.pub)
self.hashgx = SHA256(gxmpi)
self.encgx = AESCTR(self.r).encrypt(gxmpi)
self.state = STATE_AWAITING_DHKEY
return proto.DHCommit(self.encgx, self.hashgx)
def handleDHCommit(self, msg):
self.encgx = msg.encgx
self.hashgx = msg.hashgx
self.state = STATE_AWAITING_REVEALSIG
return proto.DHKey(long_to_bytes(self.dh.pub))
def handleDHKey(self, msg):
if self.state == STATE_AWAITING_DHKEY:
self.gy = bytes_to_long(msg.gy)
# check 2 <= g**y <= p-2
if not check_group(self.gy):
logger.error('Invalid g**y received: %r', self.gy)
return
self.createAuthKeys()
aesxb = self.calculatePubkeyAuth(self.enc_c, self.mac_m1)
self.state = STATE_AWAITING_SIG
self.lastmsg = proto.RevealSig(self.r, aesxb, b'')
self.lastmsg.mac = SHA256HMAC160(self.mac_m2,
self.lastmsg.getMacedData())
return self.lastmsg
elif self.state == STATE_AWAITING_SIG:
logger.info('received DHKey while not awaiting DHKEY')
if msg.gy == self.gy:
logger.info('resending revealsig')
return self.lastmsg
else:
logger.info('bad state for DHKey')
def handleRevealSig(self, msg):
if self.state != STATE_AWAITING_REVEALSIG:
logger.error('bad state for RevealSig')
raise InvalidParameterError
self.r = msg.rkey
gxmpi = AESCTR(self.r).decrypt(self.encgx)
if SHA256(gxmpi) != self.hashgx:
logger.error('Hashes don\'t match')
logger.info('r=%r, hashgx=%r, computed hash=%r, gxmpi=%r',
self.r, self.hashgx, SHA256(gxmpi), gxmpi)
raise InvalidParameterError
self.gy = read_mpi(gxmpi)[0]
self.createAuthKeys()
if msg.mac != SHA256HMAC160(self.mac_m2, msg.getMacedData()):
logger.error('HMACs don\'t match')
logger.info('mac=%r, mac_m2=%r, data=%r', msg.mac, self.mac_m2,
msg.getMacedData())
raise InvalidParameterError
self.checkPubkeyAuth(self.enc_c, self.mac_m1, msg.encsig)
aesxb = self.calculatePubkeyAuth(self.enc_cp, self.mac_m1p)
self.sessionIdHalf = True
self.onSuccess(self)
self.ourKeyid = 0
self.state = STATE_NONE
cmpmac = struct.pack(b'!I', len(aesxb)) + aesxb
return proto.Signature(aesxb, SHA256HMAC160(self.mac_m2p, cmpmac))
def handleSignature(self, msg):
if self.state != STATE_AWAITING_SIG:
logger.error('bad state (%d) for Signature', self.state)
raise InvalidParameterError
if msg.mac != SHA256HMAC160(self.mac_m2p, msg.getMacedData()):
logger.error('HMACs don\'t match')
raise InvalidParameterError
self.checkPubkeyAuth(self.enc_cp, self.mac_m1p, msg.encsig)
self.sessionIdHalf = False
self.onSuccess(self)
self.ourKeyid = 0
self.state = STATE_NONE
def createAuthKeys(self):
s = pow(self.gy, self.dh.priv, DH_MODULUS)
sbyte = pack_mpi(s)
self.sessionId = SHA256(b'\x00' + sbyte)[:8]
enc = SHA256(b'\x01' + sbyte)
self.enc_c = enc[:16]
self.enc_cp = enc[16:]
self.mac_m1 = SHA256(b'\x02' + sbyte)
self.mac_m2 = SHA256(b'\x03' + sbyte)
self.mac_m1p = SHA256(b'\x04' + sbyte)
self.mac_m2p = SHA256(b'\x05' + sbyte)
self.extraKey = SHA256(b'\xff' + sbyte)
def calculatePubkeyAuth(self, key, mackey):
pubkey = self.privkey.serializePublicKey()
buf = pack_mpi(self.dh.pub)
buf += pack_mpi(self.gy)
buf += pubkey
buf += struct.pack(b'!I', self.ourKeyid)
MB = self.privkey.sign(SHA256HMAC(mackey, buf))
buf = pubkey
buf += struct.pack(b'!I', self.ourKeyid)
buf += MB
return AESCTR(key).encrypt(buf)
def checkPubkeyAuth(self, key, mackey, encsig):
auth = AESCTR(key).decrypt(encsig)
self.theirPubkey, auth = PK.parsePublicKey(auth)
receivedKeyid, auth = proto.unpack(b'!I', auth)
if receivedKeyid == 0:
raise InvalidParameterError
authbuf = pack_mpi(self.gy)
authbuf += pack_mpi(self.dh.pub)
authbuf += self.theirPubkey.serializePublicKey()
authbuf += struct.pack(b'!I', receivedKeyid)
if self.theirPubkey.verify(SHA256HMAC(mackey, authbuf), auth) is False:
raise InvalidParameterError
self.theirKeyid = receivedKeyid
SMPPROG_OK = 0
SMPPROG_CHEATED = -2
SMPPROG_FAILED = -1
SMPPROG_SUCCEEDED = 1
class SMPHandler:
def __init__(self, crypto):
self.crypto = crypto
self.state = 1
self.g1 = DH_GENERATOR
self.g2 = None
self.g3 = None
self.g3o = None
self.x2 = None
self.x3 = None
self.prog = SMPPROG_OK
self.pab = None
self.qab = None
self.questionReceived = False
self.secret = None
self.p = None
self.q = None
def abort(self, appdata=None):
self.state = 1
self.sendTLV(proto.SMPABORTTLV(), appdata=appdata)
def sendTLV(self, tlv, appdata=None):
self.crypto.ctx.sendInternal(b'', tlvs=[tlv], appdata=appdata)
def handle(self, tlv, appdata=None):
logger.debug('handling TLV {0.__class__.__name__}'.format(tlv))
self.prog = SMPPROG_CHEATED
if isinstance(tlv, proto.SMPABORTTLV):
self.state = 1
return
is1qTlv = isinstance(tlv, proto.SMP1QTLV)
if isinstance(tlv, proto.SMP1TLV) or is1qTlv:
if self.state != 1:
self.abort(appdata=appdata)
return
msg = tlv.mpis
if not check_group(msg[0]) or not check_group(msg[3]) \
or not check_exp(msg[2]) or not check_exp(msg[5]) \
or not check_known_log(msg[1], msg[2], self.g1, msg[0], 1) \
or not check_known_log(msg[4], msg[5], self.g1, msg[3], 2):
logger.error('invalid SMP1TLV received')
self.abort(appdata=appdata)
return
self.questionReceived = is1qTlv
self.g3o = msg[3]
self.x2 = randrange(2, DH_MAX)
self.x3 = randrange(2, DH_MAX)
self.g2 = pow(msg[0], self.x2, DH_MODULUS)
self.g3 = pow(msg[3], self.x3, DH_MODULUS)
self.prog = SMPPROG_OK
self.state = 0
return
if isinstance(tlv, proto.SMP2TLV):
if self.state != 2:
self.abort(appdata=appdata)
return
msg = tlv.mpis
mp = msg[6]
mq = msg[7]
if not check_group(msg[0]) or not check_group(msg[3]) \
or not check_group(msg[6]) or not check_group(msg[7]) \
or not check_exp(msg[2]) or not check_exp(msg[5]) \
or not check_exp(msg[9]) or not check_exp(msg[10]) \
or not check_known_log(msg[1], msg[2], self.g1, msg[0], 3) \
or not check_known_log(msg[4], msg[5], self.g1, msg[3], 4):
logger.error('invalid SMP2TLV received')
self.abort(appdata=appdata)
return
self.g3o = msg[3]
self.g2 = pow(msg[0], self.x2, DH_MODULUS)
self.g3 = pow(msg[3], self.x3, DH_MODULUS)
if not self.check_equal_coords(msg[6:11], 5):
logger.error('invalid SMP2TLV received')
self.abort(appdata=appdata)
return
r = randrange(2, DH_MAX)
self.p = pow(self.g3, r, DH_MODULUS)
msg = [self.p]
qa1 = pow(self.g1, r, DH_MODULUS)
qa2 = pow(self.g2, self.secret, DH_MODULUS)
self.q = qa1*qa2 % DH_MODULUS
msg.append(self.q)
msg += self.proof_equal_coords(r, 6)
inv = invMod(mp)
self.pab = self.p * inv % DH_MODULUS
inv = invMod(mq)
self.qab = self.q * inv % DH_MODULUS
msg.append(pow(self.qab, self.x3, DH_MODULUS))
msg += self.proof_equal_logs(7)
self.state = 4
self.prog = SMPPROG_OK
self.sendTLV(proto.SMP3TLV(msg), appdata=appdata)
return
if isinstance(tlv, proto.SMP3TLV):
if self.state != 3:
self.abort(appdata=appdata)
return
msg = tlv.mpis
if not check_group(msg[0]) or not check_group(msg[1]) \
or not check_group(msg[5]) or not check_exp(msg[3]) \
or not check_exp(msg[4]) or not check_exp(msg[7]) \
or not self.check_equal_coords(msg[:5], 6):
logger.error('invalid SMP3TLV received')
self.abort(appdata=appdata)
return
inv = invMod(self.p)
self.pab = msg[0] * inv % DH_MODULUS
inv = invMod(self.q)
self.qab = msg[1] * inv % DH_MODULUS
if not self.check_equal_logs(msg[5:8], 7):
logger.error('invalid SMP3TLV received')
self.abort(appdata=appdata)
return
md = msg[5]
msg = [pow(self.qab, self.x3, DH_MODULUS)]
msg += self.proof_equal_logs(8)
rab = pow(md, self.x3, DH_MODULUS)
self.prog = SMPPROG_SUCCEEDED if self.pab == rab else SMPPROG_FAILED
if self.prog != SMPPROG_SUCCEEDED:
logger.error('secrets don\'t match')
self.abort(appdata=appdata)
self.crypto.ctx.setCurrentTrust('')
return
logger.info('secrets matched')
if not self.questionReceived:
self.crypto.ctx.setCurrentTrust('smp')
self.state = 1
self.sendTLV(proto.SMP4TLV(msg), appdata=appdata)
return
if isinstance(tlv, proto.SMP4TLV):
if self.state != 4:
self.abort(appdata=appdata)
return
msg = tlv.mpis
if not check_group(msg[0]) or not check_exp(msg[2]) \
or not self.check_equal_logs(msg[:3], 8):
logger.error('invalid SMP4TLV received')
self.abort(appdata=appdata)
return
rab = pow(msg[0], self.x3, DH_MODULUS)
self.prog = SMPPROG_SUCCEEDED if self.pab == rab else SMPPROG_FAILED
if self.prog != SMPPROG_SUCCEEDED:
logger.error('secrets don\'t match')
self.abort(appdata=appdata)
self.crypto.ctx.setCurrentTrust('')
return
logger.info('secrets matched')
self.crypto.ctx.setCurrentTrust('smp')
self.state = 1
return
def gotSecret(self, secret, question=None, appdata=None):
ourFP = self.crypto.ctx.user.getPrivkey().fingerprint()
if self.state == 1:
# first secret -> SMP1TLV
combSecret = SHA256(b'\1' + ourFP +
self.crypto.theirPubkey.fingerprint() +
self.crypto.sessionId + secret)
self.secret = bytes_to_long(combSecret)
self.x2 = randrange(2, DH_MAX)
self.x3 = randrange(2, DH_MAX)
msg = [pow(self.g1, self.x2, DH_MODULUS)]
msg += proof_known_log(self.g1, self.x2, 1)
msg.append(pow(self.g1, self.x3, DH_MODULUS))
msg += proof_known_log(self.g1, self.x3, 2)
self.prog = SMPPROG_OK
self.state = 2
if question is None:
self.sendTLV(proto.SMP1TLV(msg), appdata=appdata)
else:
self.sendTLV(proto.SMP1QTLV(question, msg), appdata=appdata)
if self.state == 0:
# response secret -> SMP2TLV
combSecret = SHA256(b'\1' + self.crypto.theirPubkey.fingerprint() +
ourFP + self.crypto.sessionId + secret)
self.secret = bytes_to_long(combSecret)
msg = [pow(self.g1, self.x2, DH_MODULUS)]
msg += proof_known_log(self.g1, self.x2, 3)
msg.append(pow(self.g1, self.x3, DH_MODULUS))
msg += proof_known_log(self.g1, self.x3, 4)
r = randrange(2, DH_MAX)
self.p = pow(self.g3, r, DH_MODULUS)
msg.append(self.p)
qb1 = pow(self.g1, r, DH_MODULUS)
qb2 = pow(self.g2, self.secret, DH_MODULUS)
self.q = qb1 * qb2 % DH_MODULUS
msg.append(self.q)
msg += self.proof_equal_coords(r, 5)
self.state = 3
self.sendTLV(proto.SMP2TLV(msg), appdata=appdata)
def proof_equal_coords(self, r, v):
r1 = randrange(2, DH_MAX)
r2 = randrange(2, DH_MAX)
temp2 = pow(self.g1, r1, DH_MODULUS) \
* pow(self.g2, r2, DH_MODULUS) % DH_MODULUS
temp1 = pow(self.g3, r1, DH_MODULUS)
cb = SHA256(struct.pack(b'B', v) + pack_mpi(temp1) + pack_mpi(temp2))
c = bytes_to_long(cb)
temp1 = r * c % SM_ORDER
d1 = (r1-temp1) % SM_ORDER
temp1 = self.secret * c % SM_ORDER
d2 = (r2 - temp1) % SM_ORDER
return c, d1, d2
def check_equal_coords(self, coords, v):
(p, q, c, d1, d2) = coords
temp1 = pow(self.g3, d1, DH_MODULUS) * pow(p, c, DH_MODULUS) \
% DH_MODULUS
temp2 = pow(self.g1, d1, DH_MODULUS) \
* pow(self.g2, d2, DH_MODULUS) \
* pow(q, c, DH_MODULUS) % DH_MODULUS
cprime = SHA256(struct.pack(b'B', v) + pack_mpi(temp1) + pack_mpi(temp2))
return long_to_bytes(c, 32) == cprime
def proof_equal_logs(self, v):
r = randrange(2, DH_MAX)
temp1 = pow(self.g1, r, DH_MODULUS)
temp2 = pow(self.qab, r, DH_MODULUS)
cb = SHA256(struct.pack(b'B', v) + pack_mpi(temp1) + pack_mpi(temp2))
c = bytes_to_long(cb)
temp1 = self.x3 * c % SM_ORDER
d = (r - temp1) % SM_ORDER
return c, d
def check_equal_logs(self, logs, v):
(r, c, d) = logs
temp1 = pow(self.g1, d, DH_MODULUS) \
* pow(self.g3o, c, DH_MODULUS) % DH_MODULUS
temp2 = pow(self.qab, d, DH_MODULUS) \
* pow(r, c, DH_MODULUS) % DH_MODULUS
cprime = SHA256(struct.pack(b'B', v) + pack_mpi(temp1) + pack_mpi(temp2))
return long_to_bytes(c, 32) == cprime
def proof_known_log(g, x, v):
r = randrange(2, DH_MAX)
c = bytes_to_long(SHA256(struct.pack(b'B', v) + pack_mpi(pow(g, r, DH_MODULUS))))
temp = x * c % SM_ORDER
return c, (r-temp) % SM_ORDER
def check_known_log(c, d, g, x, v):
gd = pow(g, d, DH_MODULUS)
xc = pow(x, c, DH_MODULUS)
gdxc = gd * xc % DH_MODULUS
return SHA256(struct.pack(b'B', v) + pack_mpi(gdxc)) == long_to_bytes(c, 32)
def invMod(n):
return pow(n, DH_MODULUS_2, DH_MODULUS)
class InvalidParameterError(RuntimeError):
pass