def configure(self):
my_private_key = self.generate_private_key()
self.my_pub_key_data = self.encode_pub_key(my_private_key.public_key())
self.bt_write(service_uuid, step1, True, "\x01\x00")
self.bt_write(service_uuid, step1plus, True, "\x01\x00")
self.bt_write(service_uuid, step1plus, False, CMD_GET_INFO)
while self.state != WR_DID_STATE:
if self.p.waitForNotifications(1.0):
# handleNotification() was called
continue
print "Waiting..."
# Perhaps do something else here
remote_key = self.decode_pub_key(self.remote_key_data)
e_share_key = self.create_e_share_key(remote_key, my_private_key)
print("eShareKey:", e_share_key.encode("hex"))
derived_key = HKDF(algorithm=hashes.SHA256(),
length=64,
salt=None,
info=b'mible-setup-info',
backend=default_backend()).derive(e_share_key)
print("HKDF result:", derived_key.encode("hex"))
token = derived_key[0:12]
bind_key = derived_key[12:28]
A = derived_key[28:44]
print("token:", token.encode("hex"))
print("bind_key:", bind_key.encode("hex"))
print("A:", A.encode("hex"))
aesccm = AESCCM(A)
nonce = bytearray([16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27])
did = "blt.3.129vl4ap05o01".encode()
aad = "devID".encode()
self.did_ct = aesccm.encrypt(nonce, did, aad)
print("AES did CT:", self.did_ct.encode("hex"))
self.bt_write(service_uuid, step1, False, CMD_WR_DID)
while self.state != FINISHED_STATE:
if self.p.waitForNotifications(1.0):
# handleNotification() was called
continue
print "Waiting..."
from cryptography.hazmat.primitives import hashes
from cryptography.hazmat.primitives.kdf.hkdf import HKDF
from pwn import *
p = process("challenge.py")
client_sk = ec.generate_private_key(ec.SECP384R1(), default_backend())
client_pk = client_sk.public_key()
client_der = client_pk.public_bytes(
encoding=serialization.Encoding.DER,
format=serialization.PublicFormat.SubjectPublicKeyInfo)
res = p.recvuntil("Send your public key (hex):")
server_der = res.split("\n")[1].decode("hex")
server_pk = serialization.load_der_public_key(server_der, default_backend())
shared_key = client_sk.exchange(ec.ECDH(), server_pk)
derived_key = HKDF(algorithm=hashes.SHA256(),
length=16,
salt=None,
info=b"handshake data",
backend=default_backend()).derive(shared_key)
p.sendline(client_der.encode('hex'))
res = p.recvuntil("Please, prove you know stuffs: ")
msg = process(["collide.py",
derived_key.encode("hex")]).recvall().split("\n")[1]
p.sendline(msg)
flag = p.recvall()
print(flag)
