Crypto-Hack-WUs

#hash birhtday conffustion from math import log, sqrt p = 0.75 H = 2**11

print(sqrt(2Hlog(1/(1-p))))

#hash birthday

from math import log

H=2**11 print(log(0.5) / log(1 - 1/H))

#hash sutfffing import json from pwn import * from Crypto.Util.number import *

2^128 collision protection!

BLOCK_SIZE = 32

Nothing up my sleeve numbers (ref: Dual_EC_DRBG P-256 coordinates)

W = [0x6b17d1f2, 0xe12c4247, 0xf8bce6e5, 0x63a440f2, 0x77037d81, 0x2deb33a0, 0xf4a13945, 0xd898c296] X = [0x4fe342e2, 0xfe1a7f9b, 0x8ee7eb4a, 0x7c0f9e16, 0x2bce3357, 0x6b315ece, 0xcbb64068, 0x37bf51f5] Y = [0xc97445f4, 0x5cdef9f0, 0xd3e05e1e, 0x585fc297, 0x235b82b5, 0xbe8ff3ef, 0xca67c598, 0x52018192] Z = [0xb28ef557, 0xba31dfcb, 0xdd21ac46, 0xe2a91e3c, 0x304f44cb, 0x87058ada, 0x2cb81515, 0x1e610046]

Lets work with bytes instead!

W_bytes = b''.join([x.to_bytes(4,'big') for x in W]) X_bytes = b''.join([x.to_bytes(4,'big') for x in X]) Y_bytes = b''.join([x.to_bytes(4,'big') for x in Y]) Z_bytes = b''.join([x.to_bytes(4,'big') for x in Z])

def pad(data): padding_len = (BLOCK_SIZE - len(data)) % BLOCK_SIZE return data + bytes([padding_len]*padding_len)

def blocks(data): return [data[i:(i+BLOCK_SIZE)] for i in range(0,len(data),BLOCK_SIZE)]

def xor(a,b): return bytes([x^y for x,y in zip(a,b)])

def rotate_left(data, x): x = x % BLOCK_SIZE return data[x:] + data[:x]

def rotate_right(data, x): x = x % BLOCK_SIZE return data[-x:] + data[:-x]

def scramble_block(block): for _ in range(40): block = xor(W_bytes, block) block = rotate_left(block, 6) block = xor(X_bytes, block) block = rotate_right(block, 17) return block

def cryptohash(msg): initial_state = xor(Y_bytes, Z_bytes) msg_padded = pad(msg) msg_blocks = blocks(msg_padded) for i,b in enumerate(msg_blocks): mix_in = scramble_block(b) for _ in range(i): mix_in = rotate_right(mix_in, i+11) mix_in = xor(mix_in, X_bytes) mix_in = rotate_left(mix_in, i+6) initial_state = xor(initial_state,mix_in) return initial_state.hex()

io = remote('socket.cryptohack.org', 13405)

i = io.recvuntil(b'JSON: ') print(i) io.send(json.dumps({'m1': "0101010101010101010101010101010101010101010101010101010101010101", 'm2': "01010101010101010101010101010101010101010101010101010101010101"}).encode()) i = io.recv() print(i)

#oh snap crypto{w1R3d_equ1v4l3nt_pr1v4cy?!}