def Handshake(password, reader, writer):
myPrivateKey = Private()
myNonce = os.urandom(32)
WriteBin(writer, myPrivateKey.get_public().serialize())
WriteBin(writer, myNonce)
theirPublicKey = ReadBin(reader)
theirNonce = ReadBin(reader)
if myNonce == theirNonce:
return None
if theirPublicKey in (b'\x00' * 32, b'\x01' + (b'\x00' * 31)):
return None
theirPublicKey = Public(theirPublicKey)
sharedKey = myPrivateKey.get_shared_key(theirPublicKey)
myProof = ComputeProof(sharedKey, theirNonce + password)
WriteBin(writer, myProof)
theirProof = ReadBin(reader)
if not VerifyProof(sharedKey, myNonce + password, theirProof):
return None
return sharedKey
def test_hashfunc(self):
priv1 = Private(seed=b"abc")
priv2 = Private(seed=b"def")
shared_sha256 = priv1.get_shared_key(priv2.get_public())
e = b"da959ffe77ebeb4757fe5ba310e28ede425ae0d0ff5ec9c884e2d08f311cf5e5"
self.assertEqual(hexlify(shared_sha256), e)
# confirm the hash function remains what we think it is
def myhash(shared_key):
return sha256(b"curve25519-shared:" + shared_key).digest()
shared_myhash = priv1.get_shared_key(priv2.get_public(), myhash)
self.assertEqual(hexlify(shared_myhash), e)
def hexhash(shared_key):
return sha1(shared_key).hexdigest().encode()
shared_hexhash = priv1.get_shared_key(priv2.get_public(), hexhash)
self.assertEqual(shared_hexhash,
b"80eec98222c8edc4324fb9477a3c775ce7c6c93a")
def test_basic(self):
secret1 = b"abcdefghijklmnopqrstuvwxyz123456"
self.assertEqual(len(secret1), 32)
secret2 = b"654321zyxwvutsrqponmlkjihgfedcba"
self.assertEqual(len(secret2), 32)
priv1 = Private(secret=secret1)
pub1 = priv1.get_public()
priv2 = Private(secret=secret2)
pub2 = priv2.get_public()
shared12 = priv1.get_shared_key(pub2)
e = b"b0818125eab42a8ac1af5e8b9b9c15ed2605c2bbe9675de89e5e6e7f442b9598"
self.assertEqual(hexlify(shared12), e)
shared21 = priv2.get_shared_key(pub1)
self.assertEqual(shared12, shared21)
pub2a = Public(pub2.serialize())
shared12a = priv1.get_shared_key(pub2a)
self.assertEqual(hexlify(shared12a), e)
from pwn import * # pip install --upgrade pwntools
from curve25519 import Private, Public
import nacl.secret
import hmac
import hashlib
HOST = 'mitm.ctfcompetition.com'
PORT = 1337
r = remote(HOST, PORT)
print('+++ Getting their keys +++')
r.sendline('s')
theirPublic = r.recv()
theirNonce = r.recv()
myPrivateKey = Private()
myNonce = os.urandom(32)
print('+++ their keys +++')
print('Server public = ' + theirPublic, 'Server nonce = ' + theirNonce)
r.sendline(myPrivateKey)
r.sendline(myNonce)
r.interactive()
#!/usr/bin/env python3
from curve25519 import Private, Public
from binascii import hexlify
keys = set()
for i in range(30):
myPrivate = Private()
val = int.to_bytes(
325606250916557431795983626356110631294008115727848805560023387167927233504,
32, 'little')
theirPublic = Public(val)
shared = myPrivate.get_shared_key(theirPublic)
print(hexlify(shared))
keys.add(shared)
print("[~] Num of different keys: {}".format(len(keys)))
###### handle passphrase
# drop argv[0] (script file name) and join rest with spaces
del sys.argv[0];
passphrase = " ".join(sys.argv);
# print passphrase inside double quotes
print("Passphrase = \"%s\""%(passphrase));
###### get long id for account
# private key from passphrase
private = sha256(passphrase.encode('utf-8')).digest();
# public key from curve25519
curve = Private(secret=private);
public = curve.get_public();
# hash public key
hashdress = sha256(public.serialize()).digest();
# create long id from hash
address = long(0);
i = 7;
while i>=0:
placevalue = pow(256,i);
try: # python 2 give character
bytesum = ord(hashdress[i]) * placevalue;
except TypeError: # python 3 gives int
bytesum = hashdress[i] * placevalue;
address += bytesum;
def test_seed(self):
# use 32-byte secret
self.assertRaises(TypeError, Private, secret=123)
self.assertRaises(TypeError, Private, secret=b"too short")
secret1 = b"abcdefghijklmnopqrstuvwxyz123456"
assert len(secret1) == 32
priv1 = Private(secret=secret1)
priv1a = Private(secret=secret1)
priv1b = Private(priv1.serialize())
self.assertEqual(priv1.serialize(), priv1a.serialize())
self.assertEqual(priv1.serialize(), priv1b.serialize())
e = b"6062636465666768696a6b6c6d6e6f707172737475767778797a313233343576"
self.assertEqual(hexlify(priv1.serialize()), e)
# the private key is a clamped form of the secret, so they won't
# quite be the same
p = Private(secret=b"\x00" * 32)
self.assertEqual(hexlify(p.serialize()), b"00" * 31 + b"40")
p = Private(secret=b"\xff" * 32)
self.assertEqual(hexlify(p.serialize()), b"f8" + b"ff" * 30 + b"7f")
# use arbitrary-length seed
self.assertRaises(TypeError, Private, seed=123)
priv1 = Private(seed=b"abc")
priv1a = Private(seed=b"abc")
priv1b = Private(priv1.serialize())
self.assertEqual(priv1.serialize(), priv1a.serialize())
self.assertEqual(priv1.serialize(), priv1b.serialize())
self.assertRaises(AssertionError, Private, seed=b"abc", secret=b"no")
priv1 = Private(seed=b"abc")
priv1a = Private(priv1.serialize())
self.assertEqual(priv1.serialize(), priv1a.serialize())
self.assertRaises(AssertionError, Private, seed=b"abc", secret=b"no")
# use built-in os.urandom
priv2 = Private()
priv2a = Private(priv2.private)
self.assertEqual(priv2.serialize(), priv2a.serialize())
# attempt to use both secret= and seed=, not allowed
self.assertRaises(AssertionError, Private, seed=b"abc", secret=b"no")
def test_errors(self):
priv1 = Private()
self.assertRaises(ValueError, priv1.get_shared_key, priv1)
from binascii import hexlify
from binascii import unhexlify
import logging
import sys
import os
from curve25519 import Private, Public
import nacl.secret
import hmac
import hashlib
from pwn import *
context.log_level = 'debug'
sk = Private()
mypk = b'\xed\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff\x7f'
pk = Public(mypk)
myshare = sk.get_shared_key(pk)
def getmac(myn):
c = remote('mitm.ctfcompetition.com', 1337)
c.sendline('c')
pk = c.recvline()
n0 = c.recvline()
c.sendline(hexlify(mypk))
c.sendline(myn)
mac = c.recvline()
c.close()
return mac
