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| import random from pwn import * from tqdm import tqdm
class MT19937: def __init__(self, seed): (MT19937.w, MT19937.n, MT19937.m, MT19937.r) = (32, 624, 397, 31) MT19937.a = 0x9908B0DF (MT19937.u, MT19937.d) = (11, 0xFFFFFFFF) (MT19937.s, MT19937.b) = (7, 0x9D2C5680) (MT19937.t, MT19937.c) = (15, 0xEFC60000) MT19937.l = 18 self.states = [seed] MT19937.lowerMask = (1 << MT19937.r) - 1 MT19937.mask = (1 << MT19937.w) - 1 MT19937.upperMask = MT19937.mask ^ MT19937.lowerMask self.index = MT19937.n MT19937.f = 1812433253
for i in range(1, self.n): self.states.append(self.mask & (i + self.f * (self.states[i-1] ^ (self.states[i-1] >> (self.w - 2)))))
def temper(self,num): num = num ^ ((num >> MT19937.u) & MT19937.d) num = num ^ ((num << MT19937.s) & MT19937.b) num = num ^ ((num << MT19937.t) & MT19937.c) num = num ^ (num >> MT19937.l) return num def rand(self): if self.index >= MT19937.n: self.twist() y = self.states[self.index] self.index += 1 return self.temper(y)
def twist(self): for i in range(MT19937.n): x = (self.states[i] & MT19937.upperMask) ^ (self.states[(i + 1) % MT19937.n] & MT19937.lowerMask) xA = x >> 1 if x & 1: xA = xA ^ self.a
self.states[i] = self.states[(i + MT19937.m) % MT19937.n] ^ xA
self.index = 0
class bitwiseMT19937: def __init__(self): self.states = [[1 << (i * 32 + j) for j in range(32)] for i in range(MT19937.n)] self.index = MT19937.n
def temper(self, num): ret = num[:] for i in range(32): if (MT19937.d >> i) & 1: if i + MT19937.u < 32: ret[i] ^= ret[i + MT19937.u]
for i in range(31, -1, -1): if (MT19937.b >> i) & 1: if i - MT19937.s >= 0: ret[i] ^= ret[i - MT19937.s]
for i in range(31, -1, -1): if (MT19937.c >> i) & 1: if i - MT19937.t >= 0: ret[i] ^= ret[i - MT19937.t] for i in range(32): if i + MT19937.l < 32: ret[i] ^= ret[i + MT19937.l] return ret def rand(self): if self.index >= MT19937.n: self.twist() y = self.states[self.index] self.index += 1 return self.temper(y)
def twist(self): for i in range(MT19937.n): x = self.states[(i + 1) % MT19937.n][:-1] + self.states[i][-1:] xA = x[1:] + [0] for t in range(32): if (MT19937.a >> t) & 1: xA[t] ^= x[0]
for t in range(32): self.states[i][t] = self.states[(i + MT19937.m) % MT19937.n][t] ^ xA[t]
self.index = 0
def count(x): ret = 0 for i in range(20000): ret ^= ((x >> i) & 1) return ret
TOTAL_BITS = 19968
linear_base = [(-1, -1) for _ in range(TOTAL_BITS)] total = 0
def add(bits, output): global total while bits: idx = bits.bit_length() - 1 if linear_base[idx] == (-1, -1): linear_base[idx] = (bits, output) total += 1 return else: bits ^= linear_base[idx][0] output ^= linear_base[idx][1]
rng = MT19937(9487) bitRng = bitwiseMT19937()
r = remote('1337pins.balsnctf.com', 27491)
def getNextOutput(debug = False): if debug: return random.getrandbits(32) % 10 else: r.sendline(b'0') tmp = r.recvline().strip() return 0 if tmp == b'.' else int(tmp)
for i in tqdm(range(20000)): bits = bitRng.rand()[0] output = getNextOutput() & 1 add(bits, output)
print(total)
for i in range(TOTAL_BITS): if linear_base[i] == (-1, -1): continue assert (linear_base[i][0] & ((1 << 31) - 1)) == 0
for i in tqdm(range(TOTAL_BITS)): if linear_base[i] == (-1, -1): linear_base[i] = (1 << i, 0) continue
mask = linear_base[i][0] ^ (1 << i) while mask: idx = mask.bit_length() - 1 linear_base[i] = (linear_base[i][0] ^ linear_base[idx][0], linear_base[i][1] ^ linear_base[idx][1]) mask ^= (1 << idx)
for i in range(TOTAL_BITS): assert linear_base[i][0] == (1 << i)
stateLong = sum((1 << i) * linear_base[i][1] for i in range(TOTAL_BITS)) states = [] for i in range(MT19937.n): states.append(stateLong & ((1 << 32) - 1)) stateLong >>= 32
rng.states = states[:]
for i in range(20000): rng.rand()
for i in range(1337): myGuess = rng.rand() % 10 r.sendline(str(myGuess)) r.recvline() r.interactive()
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