def encrypt_mt19937(seed, plaintext):
assert (seed < 2**16)
key_stream = bytearray()
r = random(seed)
while len(key_stream) < len(plaintext):
key_stream.extend(int.to_bytes(r.random(), 4, byteorder='big'))
return xor_bytes(plaintext, key_stream)
def get_output():
global secret_seed
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
now = time.time()
secret_seed = int(now)
print("Seed is: %d" % secret_seed)
r = random(secret_seed)
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
return r.random()
def get_output():
global secret_seed
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
now = time.time()
secret_seed = int(now)
print("Seed is: %d" % secret_seed)
r = random(secret_seed)
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
return r.random()
from prng import random, clone_mt19937
rand = random(42)
outputs = [rand.random() for _ in range(1000)]
cloned = clone_mt19937(outputs)
for _ in range(1000):
assert(cloned.random() == rand.random())
from prng import random
import random as pyrand
from time import sleep
import time
# sanity check
r = random(10)
values1 = [r.random() for _ in range(1000)]
r = random(10)
values2 = [r.random() for _ in range(1000)]
assert(values1 == values2)
def get_output():
global secret_seed
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
now = time.time()
secret_seed = int(now)
print("Seed is: %d" % secret_seed)
r = random(secret_seed)
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
return r.random()
output = get_output()
now = int(time.time())
from prng import random
# See the notes on MT19937 as to why we're taking values generated by C++'s
# std::mt19937 rather than Python's random.
r = random(5)
assert (r.random() == 953453411)
for _ in range(1000):
r.random()
assert (r.random() == 2924403310)
from prng import random
import random as pyrand
from time import sleep
import time
# sanity check
r = random(10)
values1 = [r.random() for _ in range(1000)]
r = random(10)
values2 = [r.random() for _ in range(1000)]
assert (values1 == values2)
def get_output():
global secret_seed
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
now = time.time()
secret_seed = int(now)
print("Seed is: %d" % secret_seed)
r = random(secret_seed)
wait = pyrand.randint(40, 1000)
sleep(wait / 100) # we're not *that* patient...
return r.random()
output = get_output()
now = int(time.time())
from prng import random, clone_mt19937
rand = random(42)
outputs = [rand.random() for _ in range(1000)]
cloned = clone_mt19937(outputs)
for _ in range(1000):
assert (cloned.random() == rand.random())
def is_mt19937_token(token, time_window=300):
seed = int(time())
return any(
random(seed + time_diff).random() == token
for time_diff in range(-time_window, time_window + 1))
def generate_mt19937_token():
seed = int(time())
return random(seed).random()
random(seed + time_diff).random() == token
for time_diff in range(-time_window, time_window + 1))
assert (decrypt_mt19937(42,
encrypt_mt19937(42,
b"Hello World!")) == b"Hello World!")
known_plaintext = b"A" * 14
# normally we want 16-bits, but it takes too long... the idea is the same here.
secret_seed = int.from_bytes(urandom(1), byteorder='big')
print("Secret seed is: %d" % secret_seed)
hidden_prefix = urandom(urandom(1)[0])
hidden_plaintext = hidden_prefix + known_plaintext
ciphertext = encrypt_mt19937(secret_seed, hidden_plaintext)
valid_seeds = (seed for seed in range(2**16)
if known_plaintext in decrypt_mt19937(seed, ciphertext))
assert (next(valid_seeds) == secret_seed)
print("Found seed!")
print("Generating token...")
token = generate_mt19937_token()
assert (is_mt19937_token(token))
print("Detected!")
print("Generating fake token...")
token = random(42).random()
assert (not is_mt19937_token(token))
print("Detected!")
