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| from hashlib import sha512,sha1
import random,sys,struct
import SocketServer
import base64 as b64
import os
import hmac
from time import time
class HandleCheckin(SocketServer.BaseRequestHandler):
N = 59244860562241836037412967740090202129129493209028128777608075105340045576269119581606482976574497977007826166502644772626633024570441729436559376092540137133423133727302575949573761665758712151467911366235364142212961105408972344133228752133405884706571372774484384452551216417305613197930780130560424424943100169162129296770713102943256911159434397670875927197768487154862841806112741324720583453986631649607781487954360670817072076325212351448760497872482740542034951413536329940050886314722210271560696533722492893515961159297492975432439922689444585637489674895803176632819896331235057103813705143408943511591629
accepted={}
def hashToInt(self,*params):
sha=sha512()
for el in params:
sha.update("%r"%el)
return int(sha.hexdigest(), 16)
def cryptrand(self,n=2048):
p1=self.hashToInt(os.urandom(40))<<1600
p1+=self.hashToInt(p1)<<1000
p1+=self.hashToInt(p1)<<500
p1+=self.hashToInt(p1)
bitmask=((2<<(n+1))-1)
p1=(p1&bitmask)
return (p1% self.N)
def sendInt(self,toSend):
s=hex(toSend)
s=s[2:]
if s[-1]=="L":
s=s[:-1]
self.request.sendall(s+"\n")
def readInt(self):
req=self.request
leng = struct.unpack("H", req.recv(2))[0]
if leng>520:
req.sendall("Sorry that is too long a number\n")
req.close()
return None
toRead = ""
while len(toRead) < leng:
toRead += req.recv(leng - len(toRead))
if len(toRead) > leng:
req.sendall("Ain't happenin today dave\n")
req.close()
return None
return int(toRead,16)
def checkBlacklist(self):
foreign=self.request.getpeername()[0]
if foreign in self.accepted:
while(len(self.accepted[foreign]) >0 and
self.accepted[foreign][0]<time()-600):
del self.accepted[foreign][0]
if len(self.accepted[foreign])>5:
self.request.send("Too many requests too quick sorry\n")
self.request.close()
return False
else:
self.accepted[foreign]=[]
return True
def doChallenge(self):
req=self.request
proof = b64.b64encode(os.urandom(12))
req.sendall("You must first solve a puzzle, a sha1 sum ending in 24 bit's set to 1, it must be of length %s bytes, starting with %s" % (len(proof)+5, proof))
test = req.recv(21)
ha = sha1()
ha.update(test)
if(not self.checkBlacklist()):
return False
if (test[0:16] != proof or
ha.digest()[-3:] != "\xff\xff\xff"):
req.sendall("NOPE")
req.close()
return False
self.accepted[self.request.getpeername()[0]].append(time())
return True
def getClientParams(self):
N=self.N
req=self.request
index=self.readInt()
if index is None:
return
if index<2 or index>N/2:#we don't have nearly that many users, we wish we did but lets be honest ,brute force attempt
req.sendall("A Wrong move against the motherland\n")
req.close()
return None
req.sendall("Please provide your ephemeral key, can never be too careful\n")
cEphemeral=self.readInt()
if cEphemeral is None:
return None
if cEphemeral%N==0:
req.sendall("The Wrong move against the motherland\n")
req.close()
return None
return cEphemeral,index
def doSlurp(self,index,cEphemeral,salt):
N=self.N
password = ""
hashToInt= self.hashToInt
salt=hashToInt(index)
storedKey = pow(index, hashToInt(salt, password), N)
multiplierSlush = 3
sEphemeralPriv = self.cryptrand()
sEphemeral = (multiplierSlush * storedKey +
pow(index, sEphemeralPriv, N)) % N
self.sendInt(salt)
self.sendInt(sEphemeral)
slush = hashToInt(cEphemeral, sEphemeral)
agreedKey = hashToInt(pow(cEphemeral * pow(storedKey, slush, N), sEphemeralPriv, N))
return agreedKey,sEphemeral
def handle(self):
N=self.N
hashToInt=self.hashToInt
req = self.request
if(not self.doChallenge()):
return
req.sendall("Welcome to Arstotzka's check in server, please provide the agent number\n")
cEphemeral,index=self.getClientParams()
salt=self.hashToInt(index)
agreedKey,sEphemeral=self.doSlurp(index,cEphemeral,salt)
gennedKey=hashToInt(hashToInt(N) ^ hashToInt(index), hashToInt(index), salt,
cEphemeral, sEphemeral, agreedKey)
check=self.readInt()
if(check==gennedKey):
req.sendall("Well done comrade, the key to the vault is {} \n")
req.close()
class ThreadedServer(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
pass
if __name__ == "__main__":
HOST, PORT = "", int(sys.argv[1])
server = ThreadedServer((HOST, PORT), HandleCheckin)
server.allow_reuse_address = True
server.serve_forever()
|
