hellman

hellman

hellman

from sage.all import *
from rejected import LFSR, taps
from binteger import Bin
from sock import Sock

n = 64
N = 2**30 + 2**29

f = Sock("mc.ax 31669")
f.send_line(str(N))

hellman

from sage.all import ZZ, GF, EllipticCurve, proof
from hashlib import scrypt

from sock import Sock
from psych import sidh, xor, G, H

proof.all(False)


def ser(*args):

hellman

hellman

hellman

'''
The idea is to reach a state consisting of 00 and FF bytes.
Because of the independence of shifts values, if the message block is the same 32-byte part repeated 2 times,
the state is preserved. We then can change the 32 byte part arbitrarily and keep the hash value unchanged.

To do this we first craft a 32x2 message block that lands on such state after 2nd round (1st round does nothing).
We have 32 bytes of freedom (-charset constraints), so this is reasonable and can be done with 1 byte guess and propagation.

One caveat is that the initial state is rather symmetric and and it's not always easy to land on a desired state,
so we prepend random block first to randomize the state.

hellman

prepare:
	mkfifo p1 p2

precomp:
	./stage1_precomp
	du -hs dump*
# 	17G	dump0
# 	17G	dump1
# 	17G	dump2
# 	17G	dump3

hellman

from sage.all import *
from crccheck.crc import *

def tobin(v, n):
    assert 0 <= v < 2**n
    return tuple(ZZ(v).digits(2, padto=n))[::-1]

def frombin(v):
    return sum(int(c)*2**i for i, c in enumerate(v[::-1]))

hellman