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auth.py
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auth.py
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#-*-coding=utf-8-*-
from __future__ import with_statement
"""
Модуль содержит класс для проверки прав на авторизацию
"""
import packet
import struct
from Crypto.Cipher import DES
from encodings import utf_16_le,hex_codec
from Crypto.Hash import MD4 as md4
from Crypto.Hash import SHA as SHA
from Crypto.Hash import MD5 as md5
from Crypto.Cipher import XOR
#import radius.eap.eap_packet as EAP
from radius.eap.eap_packet import EAP, EAP_Packet, EAP_MD5, EAP_HANDLERS, EAP_TLS, EAP_IDENTITY_CHECK_TYPES
from collections import defaultdict
from utilites import hex_bytestring
#from mppe import PPTP_MPPE
#EAP_IDENTITY_CHECK = lambda kwargs: (EAP.PW_EAP_MD5, EAP_MD5.get_challenge_reply)
EAP_IDENTITY_CHECK = lambda kwargs: (EAP.PW_EAP_TLS, EAP_TLS.get_tls_start)
EAP_ACCESS_TYPES = {'802.1x':'eap-tls', 'PPTP':'eap-md5', 'PPPOE':'eap-md5'}
def set_identity_check(identity_type):
global EAP_IDENTITY_CHECK
id_type = EAP_IDENTITY_CHECK_TYPES.get(identity_type)
if not id_type:
raise Exception("AUTH exception: Unknown EAP Identity Type: %s" % identity_type)
id_check = lambda kwargs: id_type
EAP_IDENTITY_CHECK = id_check
def set_eap_access_types(access_types):
global EAP_ACCESS_TYPES
EAP_ACCESS_TYPES = access_types
def get_eap_access_type(access_type):
eap_type = EAP_ACCESS_TYPES.get(access_type)
if not eap_type:
return EAP_IDENTITY_CHECK({})
id_type = EAP_IDENTITY_CHECK_TYPES.get(eap_type)
if not id_type:
raise Exception("AUTH GEAT exception: Unknown EAP Identity Type: %s" % eap_type)
return id_type
def get_eap_handlers():
return EAP_HANDLERS.iterkeys()
class Auth:
"""
Класс предназначен для реализации проверки авторизации для механизмов
PAP,CHAP,MSCHAP2 и генерации ответного пакета.
Для проверки имени и пароля конструктором вызывается функция _CheckAuth с параметрами username, plainpassword, secret
"""
def __init__(self, packetobject, username, password, secret, access_type, challenges={}, logger=None):
self.packet=packetobject
self.secret = secret
self.packet.secret = secret
self.access_type = access_type
self.logger = logger
self.extensions = {}
self.challenges = defaultdict(lambda:{'get': lambda x,d: None, 'set': lambda x,y: None, 'lock': None})
for challenge_type in challenges:
self.challenges[challenge_type] = challenges[challenge_type]
self.typeauth=self._DetectTypeAuth()
self.plainusername=username
self.plainpassword=password
self.code = 0
self.ident=''
self.NTResponse=''
self.PeerChallenge=''
self.AuthenticatorChallenge=''
self.attrs = None
def __repr__(self):
return ', '.join((name + str(item) for name, item in (('code: ', self.code), ('access_type: ', self.access_type),\
('secret: ', self.secret), ('auth: ', self.typeauth), \
('username: ', self.plainusername), ('password: ', self.plainpassword), \
('\n packet: ', self.packet), ('\n extensions: ', ' | '.join((str(key) +': ' + str(value) for key, value in self.extensions.iteritems()))))))
def ReturnPacket(self, packetfromcore, mppe_support=False):
self.attrs=packetfromcore._PktEncodeAttributes()
self.Reply=self.packet.CreateReply()
self.Reply.secret = self.secret
#print repr(packetfromcore)
#print repr(self.Reply)
if self.typeauth == 'EAP':
if self.code == packet.AccessReject:
eap_packet = self.extensions.get('EAP-Packet')
self.packet['EAP-Message'] = EAP_Packet.get_failure_packet(eap_packet.identifier)
elif self.code == packet.AccessChallenge:
self.Reply['State'] = self.packet['State'][0]
self.Reply.code=self.code
self.Reply['EAP-Message'] = self.packet['EAP-Message'][0]
self.Reply['Message-Authenticator'] = self.packet['Message-Authenticator'][0]
return self.Reply.ReplyPacket(), self.Reply
elif self._CheckAuth(code = self.code):
self.Reply.code=self.code
if (self.typeauth=='MSCHAP2') and (self.code!=3):
self.Reply.AddAttribute((311,26),self._MSchapSuccess())
if mppe_support:
self.add_mppe_keys()
else:
self.Reply.AddAttribute((311,7),struct.pack("!I", 0))
return self.Reply.ReplyPacket(self.attrs), self.Reply
#return self.Reply.ReplyPacket(), self.Reply
else:
self.Reply.code=packet.AccessReject
return self.Reply.ReplyPacket(), self.Reply
def _DetectTypeAuth(self):
if self.packet.has_key('User-Password') and self.access_type!='DHCP':
return 'PAP'
elif self.packet.has_key('User-Password') and self.access_type=='lISG':
return 'lISG'
elif self.packet.has_key('CHAP-Password') and self.access_type!='DHCP':
return 'CHAP'
elif self.packet.has_key('MS-CHAP-Challenge') and self.access_type!='DHCP':
return 'MSCHAP2'
elif self.packet.has_key('EAP-Message') and self.access_type!='DHCP':
eap_packet = EAP_Packet()
eap_packet.unpack_header(self.packet['EAP-Message'][0])
self.extensions['EAP-Packet'] = eap_packet
return 'EAP'
else:
return 'UNKNOWN'
def _HandlePacket(self, **kwargs):
if self.typeauth == 'EAP':
eap_packet = self.extensions.get('EAP-Packet')
if not eap_packet:
#self.code = packet.AccessReject
return False, False, 'EAP error: No EAP-Message found: %s' % self.plainusername
elif eap_packet.code not in (EAP.PW_EAP_RESPONSE,):
#self.code = packet.AccessReject
#self.packet['EAP-Message'] = EAP_Packet.get_failure_packet()
return False, False, 'EAP error: Wrong code: %s/%s' % (self.plainusername, eap_packet.code)
else:
eap_handler = EAP_HANDLERS.get(eap_packet.type)
if not eap_handler:
return False, False, 'EAP error: unknown type: %s/%s' % (self.plainusername, eap_packet.type)
eap_packet = eap_handler()
eap_packet.unpack(self.packet['EAP-Message'][0])
self.extensions['EAP-Packet'] = eap_packet
return True, True, ''
else:
return True, True, ''
def _ProcessPacket(self, **kwargs):
if self.typeauth == 'EAP':
eap_packet = self.extensions.get('EAP-Packet')
if not eap_packet:
return False, False, 'EAP error: No EAP-Message found: %s' % self.plainusername
if eap_packet.type == EAP.PW_EAP_IDENTITY:
#assume that User-Name is checked as a radius attribute User-Name
self.code = packet.AccessChallenge
eap_packet.identifier = (eap_packet.identifier + 1) % 255
auth_name, auth_handler = get_eap_access_type(self.access_type)
self.packet['EAP-Message'], challenge = auth_handler(eap_packet)
state = self.plainusername[:3] + '00'
self.packet['State'] = state
if challenge:
with self.challenges[auth_name]['lock']:
self.challenges[auth_name]['set'](self.plainusername, (challenge, eap_packet.identifier, state))
return False, True, 'EAP: challenge issued: %s' % self.plainusername
elif eap_packet.type == EAP.PW_EAP_NAK:
self.code = packet.AccessChallenge
auth_name, auth_handler = EAP_IDENTITY_CHECK({})
with self.challenges[auth_name]['lock']:
old_challenge, old_id, old_state = self.challenges[auth_name]['get'](self.plainusername, (None, None, None))
if not old_id or not ((old_id == eap_packet.identifier) or (old_id == eap_packet.identifier - 1)):
return False, False, 'EAP error: wrong identifiers for user: %s old: %s new: %s' % (self.plainusername, old_id,eap_packet.identifier)
eap_packet.identifier = (eap_packet.identifier + 1) % 255
eap_handler = EAP_HANDLERS.get(eap_packet.req_auth)
if not eap_handler:
return False, False, 'EAP error: unknown requested auth method: %s %s' % (self.plainusername, eap_packet.req_auth)
self.packet['EAP-Message'], challenge = eap_handler.get_challenge_reply(eap_packet)
state = self.plainusername[:3] + '01'
self.packet['State'] = state
if challenge:
with self.challenges[eap_packet.req_auth]['lock']:
self.challenges[eap_packet.req_auth]['set'](self.plainusername, (challenge, eap_packet.identifier, state))
return False, True, 'EAP: post NAK challenge issued: %s auth type %s' % (self.plainusername, eap_packet.req_auth)
else:
return True, True, ''
else:
return True, True, ''
def _EAP_Check(self):
eap_packet = self.extensions.get('EAP-Packet')
if eap_packet.type == EAP.PW_EAP_MD5:
with self.challenges[EAP.PW_EAP_MD5]['lock']:
challenge, id, state = self.challenges[EAP.PW_EAP_MD5]['get'](self.plainusername, (None, None, None))
if challenge is None:
return False, 'EAP Password check: issued challenge not found: %s' % self.plainusername
#print hex_bytestring(challenge)
#print hex_bytestring(md5.new(''.join((struct.pack("!B", id), self.plainpassword, challenge))).digest())
if eap_packet.check_response(self.plainpassword, challenge, id):
self.code = packet.AccessAccept
self.packet['EAP-Message'] = EAP_MD5.get_success_packet(eap_packet.identifier)
return True, ''
else:
return False, 'EAP Password check: wrong password: %s' % self.plainusername
else:
return False, 'EAP Password check: type not implemented: %s/%s' % (self.plainusername, eap_packet.type)
def EAP_Reply(self):
if self.code == packet.AccessAccept:
return EAP_MD5.get_success_packet(self.extensions['eap-packet'].identifier)
def set_code(self, code):
self.code = code
def check_auth(self):
return self._CheckAuth()
def _CheckAuth(self, code= packet.AccessAccept, **kwargs):
"""
Функция, в зависимости от типа авторизации, вызывает разные методы для определения правильности
логина и пароля.
To Do: Если ядро ответило: доступ запретить-пропускаем.
"""
if self.access_type=='DHCP' or self.access_type=='lISG':
return True, ''
if code not in (packet.AccessReject, packet.AccessChallenge):
if self.typeauth=='PAP':
#print self._PwDecrypt()
if self._PwDecrypt():
#print 'pap=', True
return True, ''
elif self.typeauth=='CHAP':
if self._CHAPDecrypt():
return True, ''
elif self.typeauth=='MSCHAP2':
#print "mschap2"
if self._MSCHAP2Decrypt():
return True, ''
elif self.typeauth == 'EAP':
return self._EAP_Check()
return False, 'Password check: bad password: %s' % self.plainusername
def add_mppe_keys(self):
magic1 = \
"\x54\x68\x69\x73\x20\x69\x73\x20\x74" + \
"\x68\x65\x20\x4d\x50\x50\x45\x20\x4d" + \
"\x61\x73\x74\x65\x72\x20\x4b\x65\x79"
SHSpad1 = "\x00"*40
SHSpad2 = "\xf2"*40
Magic2 = \
"\x4f\x6e\x20\x74\x68\x65\x20\x63\x6c\x69" + \
"\x65\x6e\x74\x20\x73\x69\x64\x65\x2c\x20" + \
"\x74\x68\x69\x73\x20\x69\x73\x20\x74\x68" + \
"\x65\x20\x73\x65\x6e\x64\x20\x6b\x65\x79" + \
"\x3b\x20\x6f\x6e\x20\x74\x68\x65\x20\x73" + \
"\x65\x72\x76\x65\x72\x20\x73\x69\x64\x65" + \
"\x2c\x20\x69\x74\x20\x69\x73\x20\x74\x68" + \
"\x65\x20\x72\x65\x63\x65\x69\x76\x65\x20" + \
"\x6b\x65\x79\x2e"
Magic3 = \
"\x4f\x6e\x20\x74\x68\x65\x20\x63\x6c\x69" + \
"\x65\x6e\x74\x20\x73\x69\x64\x65\x2c\x20" + \
"\x74\x68\x69\x73\x20\x69\x73\x20\x74\x68" + \
"\x65\x20\x72\x65\x63\x65\x69\x76\x65\x20" + \
"\x6b\x65\x79\x3b\x20\x6f\x6e\x20\x74\x68" + \
"\x65\x20\x73\x65\x72\x76\x65\x72\x20\x73" + \
"\x69\x64\x65\x2c\x20\x69\x74\x20\x69\x73" + \
"\x20\x74\x68\x65\x20\x73\x65\x6e\x64\x20" + \
"\x6b\x65\x79\x2e"
masterSessionKey=SHA.new(self._NtPasswordHash(self.plainpassword)+self.NTResponse+magic1).digest()[:16]
sendMasterKey = SHA.new(masterSessionKey+SHSpad1+Magic3+SHSpad2).digest()[:16]
recvMasterKey = SHA.new(masterSessionKey+SHSpad1+Magic2+SHSpad2).digest()[:16]
salt = "\x80\x01"
#P = '\x0f'+recvMasterKey+'\x00'*15
P = bytearray(struct.pack("!B16s15x", 16, recvMasterKey))
b1=bytearray(md5.new(self.secret+self.packet.authenticator+salt).digest())
res=''
for i in xrange(0,16):
P[i] ^= b1[i]
m=bytearray(md5.new(self.secret+self.packet.authenticator).digest())
for i in xrange(0,16):
P[16+i]^=m[i]
recvkey = str(salt+P)
salt = "\x80\x02"
P = bytearray(struct.pack("!B16s15x", 16,sendMasterKey))
b1=bytearray(md5.new(self.secret+self.packet.authenticator+salt).digest())
res=''
for i in xrange(0,16):
P[i] ^= b1[i];
m=bytearray(md5.new(self.secret+self.packet.authenticator).digest())
for i in xrange(0,16):
P[16+i]^=m[i]
sendkey = str(salt+P)
#encryption policy
self.Reply.AddAttribute((311,7),struct.pack("!I", 2))
#encryption type
self.Reply.AddAttribute((311,8),struct.pack("!I", 6))
self.Reply.AddAttribute((311,16),sendkey)
self.Reply.AddAttribute((311,17),recvkey)
#===============================================================================
# def add_mppe_keys_v2(self):
# def rc4crypt(data, key):
# x = 0
# box = range(256)
# for i in range(256):
# x = (x + box[i] + ord(key[i % len(key)])) % 256
# box[i], box[x] = box[x], box[i]
# x,y = 0, 0
# out = []
# for char in data:
# x = (x + 1) % 256
# y = (y + box[x]) % 256
# box[x], box[y] = box[y], box[x]
# out.append(chr(ord(char) ^ box[(box[x] + box[y]) % 256]))
# return ''.join(out)
#
# magic1 = \
# "\x54\x68\x69\x73\x20\x69\x73\x20\x74" + \
# "\x68\x65\x20\x4d\x50\x50\x45\x20\x4d" + \
# "\x61\x73\x74\x65\x72\x20\x4b\x65\x79"
#
# SHSpad1 = "\x00"*40
# SHSpad2 = "\xf2"*40
#
# Magic2 = \
# "\x4f\x6e\x20\x74\x68\x65\x20\x63\x6c\x69" + \
# "\x65\x6e\x74\x20\x73\x69\x64\x65\x2c\x20" + \
# "\x74\x68\x69\x73\x20\x69\x73\x20\x74\x68" + \
# "\x65\x20\x73\x65\x6e\x64\x20\x6b\x65\x79" + \
# "\x3b\x20\x6f\x6e\x20\x74\x68\x65\x20\x73" + \
# "\x65\x72\x76\x65\x72\x20\x73\x69\x64\x65" + \
# "\x2c\x20\x69\x74\x20\x69\x73\x20\x74\x68" + \
# "\x65\x20\x72\x65\x63\x65\x69\x76\x65\x20" + \
# "\x6b\x65\x79\x2e"
#
# Magic3 = \
# "\x4f\x6e\x20\x74\x68\x65\x20\x63\x6c\x69" + \
# "\x65\x6e\x74\x20\x73\x69\x64\x65\x2c\x20" + \
# "\x74\x68\x69\x73\x20\x69\x73\x20\x74\x68" + \
# "\x65\x20\x72\x65\x63\x65\x69\x76\x65\x20" + \
# "\x6b\x65\x79\x3b\x20\x6f\x6e\x20\x74\x68" + \
# "\x65\x20\x73\x65\x72\x76\x65\x72\x20\x73" + \
# "\x69\x64\x65\x2c\x20\x69\x74\x20\x69\x73" + \
# "\x20\x74\x68\x65\x20\x73\x65\x6e\x64\x20" + \
# "\x6b\x65\x79\x2e"
#
#
# #masterSessionKey=SHA.new(self._NtPasswordHash(self.plainpassword)+self.NTResponse+magic1).digest()[:16]
# #
# passwordhash = self._NtPasswordHash(self.password)
#
# md4_context = md4.new() #Эксперимент с нативной md4 библиотекой
# md4_context.update(passwordhash) #
# passwordhashhash = md4_context.digest() #
#
# masterSessionKey=SHA.new(passwordhashhash[:16]+self.NTResponse[:24]+magic1).digest()[:16]
#
#
# sendMasterKey = SHA.new(masterSessionKey+SHSpad1+Magic3+SHSpad2).digest()[:16]
# recvMasterKey = SHA.new(masterSessionKey+SHSpad1+Magic2+SHSpad2).digest()[:16]
#
#
#
# #encryption policy
# self.Reply.AddAttribute((311,7),struct.pack("!I", 1))
#
# #encryption type
# self.Reply.AddAttribute((311,8),struct.pack("!I", 4))
#
# self.Reply.AddAttribute((311,16),sendkey)
# self.Reply.AddAttribute((311,17),recvkey)
#
# def add_mppe_keys_v3(self):
# instance = PPTP_MPPE(self.plainpassword, self.NTResponse)
# self.Reply.AddAttribute((311,7),struct.pack("!i", 1))
#
# #encryption type
# self.Reply.AddAttribute((311,8),struct.pack("!i", 4))
#
# print instance.ssk, instance.srk
#
# self.Reply.AddAttribute((311,16), instance.ssk)
# self.Reply.AddAttribute((311,17), instance.srk)
#===============================================================================
def _MSCHAP2Decrypt(self):
(self.ident, var, self.PeerChallenge, reserved, self.NTResponse)=struct.unpack("!BB16s8s24s",self.packet['MS-CHAP2-Response'][0])
self.AuthenticatorChallenge=self.packet.get('MS-CHAP-Challenge', [''])[0]
return self.NTResponse==self._GenerateNTResponse(self.AuthenticatorChallenge, self.PeerChallenge, self.plainusername, self.plainpassword)
def _CHAPDecrypt(self):
(ident , password)=struct.unpack('!B16s',self.packet['CHAP-Password'][0])
if self.packet.has_key('CHAP-Challenge'):
pck="%s%s%s" % (struct.pack('!B',ident),self.plainpassword,self.packet.get('CHAP-Challenge', [''])[0])
else:
pck="%s%s%s" % (struct.pack('!B',ident),self.plainpassword,self.packet.authenticator)
return md5.new(pck).digest()==password
def _PwDecrypt(self):
"""
Функция расшифровывает пароль из атрибута 2 (Password) с помощью секретного ключа, и аутентикатора
Используется только в алгоритме PAP
Unobfuscate a RADIUS password
RADIUS hides passwords in packets by using an algorithm
based on the MD5 hash of the pacaket authenticator and RADIUS
secret. This function reverses the obfuscation process.
@param password: obfuscated form of password
@type password: string
@return: plaintext password
@rtype: string
"""
pw=''
password=self.packet["User-Password"][0]
authenticator=self.packet.authenticator
while password:
hash=md5.new(self.secret+authenticator).digest()
for i in range(16):
pw+=chr(ord(hash[i]) ^ ord(password[i]))
(authenticator,password)=(password[:16], password[16:])
while pw.endswith("\x00"):
pw=pw[:-1]
if self.logger:
self.logger.debug("PAP user=%s password=%s", (self.plainusername, pw))
return pw==self.plainpassword
#Функции для генерации MSCHAP2 response
def _convert_key(self, key):
"""
Converts a 7-bytes key to an 8-bytes key based on an algorithm.
Функция для дополнения ключа до длины, кратной 8-ми
"""
assert len(key) == 7, "NTLM convert_key needs 7-byte key"
bytes = [key[0],
chr(((ord(key[0]) << 7) & 0xFF) | (ord(key[1]) >> 1)),
chr(((ord(key[1]) << 6) & 0xFF) | (ord(key[2]) >> 2)),
chr(((ord(key[2]) << 5) & 0xFF) | (ord(key[3]) >> 3)),
chr(((ord(key[3]) << 4) & 0xFF) | (ord(key[4]) >> 4)),
chr(((ord(key[4]) << 3) & 0xFF) | (ord(key[5]) >> 5)),
chr(((ord(key[5]) << 2) & 0xFF) | (ord(key[6]) >> 6)),
chr( (ord(key[6]) << 1) & 0xFF),
]
return "".join([ self._set_odd_parity(b) for b in bytes ])
def _set_odd_parity (self,byte):
"""
Turns one-byte into odd parity. Odd parity means that a number in
binary has odd number of 1's.
Функция для дополнения ключа до длины, кратной 8-ми
"""
assert len(byte) == 1
parity = 0
ordbyte = ord(byte)
for dummy in range(8):
if (ordbyte & 0x01) != 0:
parity += 1
ordbyte >>= 1
ordbyte = ord(byte)
if parity % 2 == 0:
if (ordbyte & 0x01) != 0:
ordbyte &= 0xFE
else:
ordbyte |= 0x01
return chr(ordbyte)
def _ChallengeHash(self, PeerChallenge, AuthenticatorChallenge, username):
return SHA.new("%s%s%s" % (PeerChallenge, AuthenticatorChallenge, username)).digest()[0:8]
def _NtPasswordHash(self, password, utf16=True):
"""Generate a NT password hash.
The NT password hash is a MD4 hash of the UTF-16 little endian
encoding of the password.
"""
if utf16==True:
pw=password.encode("utf-16-le")
else:
pw=password
md4_context = md4.new() #Эксперимент с нативной md4 библиотекой
md4_context.update(pw) #
hash = md4_context.digest() #
return hash
def _GenerateNTResponse(self, authchallenge, peerchallenge, username, password):
"""
Генерируем 24-битное значение ответа клиента на challenge-запрос сервера
чтобы сравнить с полученным от NAS значением. Если совпадают-авторизировать пользователя.
"""
challenge = self._ChallengeHash(peerchallenge, authchallenge, username)
passwordhash = self._NtPasswordHash(password)
return self._ChallengeResponse(challenge, passwordhash)
def _ChallengeResponse(self, challenge, pwhash):
"""Calculate a response to a password challenge.
The challenge-response algorithm is based on DES encoding:
the challenge is encoded three times with the three successive
7-byte blocks from the password hash.
"""
# По алгоритму дополняем нолями MD4 хэш пароля до 21 символа
pwhash+='\x00' * (21-len(pwhash))
resp=''
for i in range(3):
desk=DES.new(self._convert_key(pwhash[i*7:(i+1)*7]), DES.MODE_ECB)
resp+=desk.encrypt(challenge)
return resp
def _MSchapSuccess(self):
return struct.pack("!BBB42s", 26, 45, self.ident, self._GenerateAuthenticatorResponse())
def _GenerateAuthenticatorResponse(self):
magic1= \
"\x4D\x61\x67\x69\x63\x20\x73\x65" + \
"\x72\x76\x65\x72\x20\x74\x6F\x20" + \
"\x63\x6C\x69\x65\x6E\x74\x20\x73" + \
"\x69\x67\x6E\x69\x6E\x67\x20\x63" + \
"\x6F\x6E\x73\x74\x61\x6E\x74"
magic2= \
"\x50\x61\x64\x20\x74\x6F\x20\x6D" + \
"\x61\x6B\x65\x20\x69\x74\x20\x64" + \
"\x6F\x20\x6D\x6F\x72\x65\x20\x74" + \
"\x68\x61\x6E\x20\x6F\x6E\x65\x20" + \
"\x69\x74\x65\x72\x61\x74\x69\x6F" + \
"\x6E"
pwhash=self._NtPasswordHash(self.plainpassword)
pwhashash=self._NtPasswordHash(pwhash,False)
digest=SHA.new(pwhashash+self.NTResponse+magic1).digest()
challenge=self._ChallengeHash(self.PeerChallenge, self.AuthenticatorChallenge, self.plainusername)
digest=SHA.new(digest+challenge+magic2).digest()
return "S="+digest.encode("hex").upper()