def toTxt(key,iv,seq,msg):
assert(len(key) == 16)
assert(len(iv) == 8)
seq_txt = struct.pack('I',seq)
pkl = cPickle.dumps(msg,cPickle.HIGHEST_PROTOCOL)
txt = seq_txt + pkl.encode('zip')
enc = xtea.crypt(key,txt,iv)
result = enc.encode('base64').strip()
return result
def toTxt(key, iv, seq, msg):
assert (len(key) == 16)
assert (len(iv) == 8)
seq_txt = struct.pack('I', seq)
pkl = cPickle.dumps(msg, cPickle.HIGHEST_PROTOCOL)
txt = seq_txt + pkl.encode('zip')
enc = xtea.crypt(key, txt, iv)
result = enc.encode('base64').strip()
return result
def fromTxt(key, iv, expected_seq, txt):
seq_size = struct.calcsize('I')
dec = xtea.crypt(key, txt.decode('base64'), iv)
seq = struct.unpack('I', dec[:seq_size])[0]
if (seq != expected_seq):
raise MsgSequenceError(seq, expected_seq)
pkl = dec[seq_size:].decode('zip')
msg = cPickle.loads(pkl)
return msg
def fromTxt(key,iv,expected_seq,txt):
seq_size = struct.calcsize('I')
dec = xtea.crypt(key,txt.decode('base64'),iv)
seq = struct.unpack('I',dec[:seq_size])[0]
if(seq != expected_seq):
raise MsgSequenceError(seq,expected_seq)
pkl = dec[seq_size:].decode('zip')
msg = cPickle.loads(pkl)
return msg
def toFlag(self,txt):
txt = txt.strip()
size = struct.calcsize("<IIId")
if(len(txt) <= 3+size):
raise FlagParseException(txt)
if(txt.startswith("FLG") == False):
raise FlagParseException(txt)
try:
enc = base64.urlsafe_b64decode(txt[3:])
dec = xtea.crypt(self.key,enc,self.iv)
packed = dec[:size]
sig = dec[size:]
except Exception as e:
raise FlagParseException(str(e))
if(sig != hmac.new(self.phrase,packed,hashlib.md5).digest()):
raise FlagParseException(txt)
teamId,serviceId,round,timestamp = struct.unpack("<IIId",packed)
return Flag(teamId,serviceId,round,timestamp)
def toFlag(self, txt):
txt = txt.strip()
size = struct.calcsize("<BBId")
if (len(txt) <= 3 + size):
raise FlagParseException(txt)
if (txt.startswith("FLG") == False):
raise FlagParseException(txt)
try:
enc = base64.urlsafe_b64decode(txt[3:])
dec = xtea.crypt(self.key, enc, self.iv)
packed = dec[:size]
sig = dec[size:]
except Exception as e:
raise FlagParseException(str(e))
if (sig != hmac.new(self.phrase, packed, hashlib.md5).digest()[:12]):
raise FlagParseException(txt)
teamId, serviceId, round, timestamp = struct.unpack("<BBId", packed)
return Flag(teamId, serviceId, round, timestamp)
def toTxt(self,flag):
packed = struct.pack("<IIId",flag.teamId,flag.serviceId,flag.round,flag.timestamp)
sig = hmac.new(self.phrase,packed,hashlib.md5).digest()
enc = xtea.crypt(self.key,packed+sig,self.iv)
return "FLG"+base64.urlsafe_b64encode(enc)
def toTxt(self, flag):
packed = struct.pack("<BBId", flag.teamId, flag.serviceId, flag.round,
flag.timestamp)
sig = hmac.new(self.phrase, packed, hashlib.md5).digest()[:12]
enc = xtea.crypt(self.key, packed + sig, self.iv)
return "FLG" + base64.urlsafe_b64encode(enc)
