If I'd be any of you, I'd let anyone that thinks that an "contiguous 80-bits missing and 256 - 80 bits known" problem is a 256-bits problem, to continue in believing so... rather than getting annoyed trying to explain some obvious things, maybe speed up your Python.
import os
import math
import time
from gmpy2 import gmpy2
class S: # Scalar field
N = 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141
N_2 = (N + 1) // 2 # 2**-1 mod N
gmp_N = gmpy2.mpz(N)
@staticmethod
def add(a, b):
return gmpy2.mod(gmpy2.add(a, b,), S.gmp_N)
@staticmethod
def mul(a, b):
return gmpy2.mod(gmpy2.mul(a, b), S.gmp_N)
class F: # Curve field
P = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f
gmp_P = gmpy2.mpz(P)
gmp_P4 = gmpy2.mpz((P + 1) // 4)
@staticmethod
def add(a, b):
return gmpy2.mod(gmpy2.add(a, b), F.gmp_P)
@staticmethod
def mul(a, b):
return gmpy2.mod(gmpy2.mul(a, b), F.gmp_P)
@staticmethod
def pow(b, e):
return gmpy2.powmod(b, e, F.gmp_P)
@staticmethod
def sqrt(a):
return gmpy2.powmod(a, F.gmp_P4, F.gmp_P)
@staticmethod
def inv(a):
return gmpy2.invert(a, F.gmp_P)
class Point: # Affine point
def __init__(self, x, y, parity=-1):
self.x = x
self.y = y if parity == -1 else Point.calc_y(x, parity)
@classmethod
def uncompress(cls, s):
parity, xh = int(s[:2], 16), s[2:]
if parity not in [2, 3]:
raise Exception("Expected parity 02 or 03")
return Point(int(xh, 16), 0, parity % 2)
@staticmethod
def calc_y(x, parity):
y = F.sqrt(F.add(F.pow(x, 3), 7)) # y = sqrt(x**3 + 7)
return y if parity == y % 2 else F.P - y
class JPoint: # Jacobian point
def __init__(self, x, y, z):
self.x = x
self.y = y
self.z = z
def affine(self):
z = F.inv(self.z)
z2 = F.mul(z, z)
return Point(F.mul(self.x, z2), F.mul(self.y, F.mul(z, z2)))
def mul(self, n):
if self.y == 0 or n == 0:
return JPoint(0, 0, 1)
if n == 1:
return self
if n < 0 or n >= S.N:
return self.mul(n % S.N)
if (n % 2) == 0:
return self.mul(n // 2).double()
return self.mul(n // 2).double().add(self)
def double(self):
if self.y == 0:
return JPoint(0, 0, 0)
y2 = F.mul(self.y, self.y)
s = F.mul(4 * self.x, y2)
n = F.mul(3 * self.x, self.x)
x = F.add(F.mul(n, n), - 2 * s)
return JPoint(x, F.add(F.mul(n, s - x), -F.mul(8 * y2, y2)), F.mul(2 * self.y, self.z))
def add(self, q):
if self.y == 0:
return q
if q.y == 0:
return self
qz2 = F.mul(q.z, q.z)
pz2 = F.mul(self.z, self.z)
u1 = F.mul(self.x, qz2)
u2 = F.mul(q.x, pz2)
s1 = F.mul(self.y, F.mul(q.z, qz2))
s2 = F.mul(q.y, F.mul(self.z, pz2))
if u1 == u2:
if s1 != s2:
return JPoint(0, 0, 1)
return self.double()
h = F.add(u2, -u1)
r = F.add(s2, -s1)
h2 = F.mul(h, h)
h3 = F.mul(h, h2)
u1h2 = F.mul(u1, h2)
nx = F.add(F.mul(r, r), -F.add(h3, 2 * u1h2))
ny = F.add(F.mul(r, F.add(u1h2, -nx)), -F.mul(s1, h3))
nz = F.mul(h * self.z, q.z)
return JPoint(nx, ny, nz)
class Group:
G = Point(
0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798,
0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8
)
@staticmethod
def add(p: Point, q: Point):
if p.x == q.x:
raise Exception('Point adding with same X not supported')
m = F.mul(F.add(p.y, -q.y), F.inv(F.add(p.x, -q.x)))
x = F.add(F.add(F.mul(m, m), -p.x), -q.x)
return Point(x, F.add(F.mul(m, F.add(q.x, -x)), -q.y))
@classmethod
def mul(cls, p: Point, k):
return JPoint(p.x, p.y, 1).mul(k).affine()
@classmethod
def batch_add(cls, ga, gb):
n = len(ga)
d = [0] * n
p = [0] * n
z = 1
for i in range(n):
d[i] = F.add(ga[i].x, -gb[i].x)
z = F.mul(z, d[i])
p[i] = z
t = F.inv(z)
for i in range(n - 1, -1, -1):
if i > 0:
xi = F.mul(t, p[i - 1])
t = F.mul(t, d[i])
else:
xi = t
m = F.mul(F.add(ga[i].y, -gb[i].y), xi)
ga[i].x = F.add(F.add(F.mul(m, m), -ga[i].x), -gb[i].x)
ga[i].y = F.add(F.mul(m, F.add(gb[i].x, -ga[i].x)), -gb[i].y)
class TrueRandom:
def __init__(self, max_value: int, num_bits: int, min_value: int = 0):
self.upper_bound = max_value - min_value + 1
self.min = min_value
self.num_bits = num_bits
self.domain = 2 ** num_bits
self.num_bytes = math.ceil(num_bits / 8)
self.shift = 8 * self.num_bytes - num_bits
def get_next(self):
random_bytes = os.urandom(self.num_bytes)
# trim to num_bits
random_int = int.from_bytes(random_bytes, byteorder='big') >> self.shift
# normalize from domain range to target range
sample = self.upper_bound * random_int // self.domain
return sample + self.min
class Kangaroo:
def __init__(self, k1: int, k2: int, dp: int, herd_size: int,
verify: bool = False):
self.key_offset = k1
b = k2 - k1 + 1
# subtract k1 to search in [0, b) interval
k2 -= k1
k1 = 0
self.k1 = k1
self.k2 = k2
self.b = b
self.dp = dp
self.herd_size = herd_size
self.verify = verify
self.m = herd_size + herd_size # m/2 + m/2
# compute optimal alpha for minimum expected total group operations
# numJumps(a) = (b/4a + 4a/m**2) * m; minimal when a = m * sqrt(b)/4
alpha = herd_size * math.sqrt(b) / 2
self.jump_distances, self.jump_points, _ = self.build_jump_distances(alpha, with_points=True)
self.n = len(self.jump_distances)
# ensure we'll never stumble a kang onto a jump point (erase doubling branch)
self.key_offset -= (2 ** (self.n + 10) + 1)
self.k1 += (2 ** (self.n + 10) + 1)
self.k2 += (2 ** (self.n + 10) + 1)
self.alpha_real = sum(self.jump_distances) / self.n
# adjust alpha to the actual average jump distance
self.alpha_expected = alpha
# (b/(4m * sqrt(b)/4) + 4(m * sqrt(b)/4)/m**2) * m == 2 sqrt(b)
self.expected_total_jumps = 2 * math.sqrt(b)
# set v to the "partition" size for a processor, and not a power of two
# v = b // m - 1 # (b/2) / (m/2)
self.v = 37
# DP overhead assuming we jump all herds at once, at every step
self.expected_total_jumps += (1 << self.dp) * self.m
self.avg_jumps_per_kang = self.expected_total_jumps / self.m
self.hashmap = {}
self.tames: list[Point | None] = [None] * herd_size
self.t_dist = [0] * herd_size
self.wilds: list[Point | None] = [None] * herd_size
self.w_dist = [0] * herd_size
self.P = self.P_neg = None
self.num_created = 0
self.batch_jp: list = [None] * herd_size # buffer for batched group operations
def solve(self, target_point: Point):
# shift P to the left to bring DLP in search interval
target_point = Group.add(target_point, Group.mul(Group.G, -self.key_offset))
self.P = target_point
self.num_created = 0
self.hashmap.clear()
k_cand, counter, tbl_size = self.kangaroo()
failed = self.verify
for i in range(len(k_cand)):
if failed:
q = Group.mul(Group.G, k_cand[i])
if q.x == self.P.x and q.y == self.P.y:
failed = False
print(f'Private Key: {hex(S.add(k_cand[i], self.key_offset))}')
k_cand[i] = S.add(k_cand[i], self.key_offset)
if failed:
raise Exception(f'Solution verify failed!\n{k_cand}')
return k_cand, counter, tbl_size
def create_kangaroo(self, kang_type, pos: int, v: int):
k1, k2 = self.k1, self.k2
if kang_type == 0:
d = self.b // 2 + pos * v # b/2 + i * v
self.t_dist[pos] = d
self.tames[pos] = Group.mul(Group.G, k1 + d)
else:
d = pos * v # 0 + i * v
self.w_dist[pos] = d
self.wilds[pos] = Group.add(self.P, Group.mul(Group.G, d))
def check_col(self, kang_type, pos, dp_mask):
k1, k2, hashmap = self.k1, self.k2, self.hashmap
if kang_type == 0:
herd, dist = self.tames, self.t_dist
else:
herd, dist = self.wilds, self.w_dist
x = herd[pos].x # shift >> 192 too expensive in Python
if (x & dp_mask) == 0:
item = hashmap.get(x)
if item is not None:
if item[0] != kang_type:
# collision
d_wild, d_tame = (item[1], dist[pos]) if kang_type == 0 else (dist[pos], item[1])
# k1 + tameDist == k + wildDist
return [
S.add(k1 + d_tame, -d_wild), # k1 + t = k + w (k > 0)
], 0
else:
# move forward
d = 7
dist[pos] += d
herd[pos] = Group.add(herd[pos], Group.mul(Group.G, d))
# this will recurse until a non-dead kangaroo is produced
k, created = self.check_col(kang_type, pos, dp_mask)
self.num_created += created
return k, 1 + created
else:
hashmap[x] = kang_type, dist[pos]
return 0, 0
@staticmethod
def build_jump_distances(alpha, with_points=False):
jump_points_fwd = None
jump_points_bwd = None
jump_distances = []
# compute |A| as powers of two for all elements but the last
# and adjust the last element so that avg(A) == alpha
r = 0
s = 0
while True:
jump_distance = 2 ** r
s += jump_distance
r += 1
a = s / r
if a < alpha:
jump_distances.append(jump_distance)
else:
total = s - jump_distance
last_dist = int(alpha * r - total)
jump_distances.append(last_dist)
break
if with_points:
jump_points_fwd, jump_points_bwd = Kangaroo.create_jump_points(jump_distances)
return jump_distances, jump_points_fwd, jump_points_bwd
@staticmethod
def create_jump_points(jump_distances: list, base_p = Group.G):
jump_points_fwd = []
jump_points_bwd = []
for dist in jump_distances:
q = Group.mul(base_p, dist)
jump_points_fwd.append(q)
jump_points_bwd.append(Point(q.x, F.P - q.y))
return jump_points_fwd, jump_points_bwd
def kangaroo(self):
k1, k2, dp, herd_size = self.k1, self.k2, self.dp, self.herd_size
print(
f' kangaroos (m): {self.m}'
f'\n jump distances |A|: {self.n}'
f'\n avg jumps / kang: {self.avg_jumps_per_kang:.0f}'
f'\n expected total jumps: {self.expected_total_jumps:20.0f} {math.log2(self.expected_total_jumps):.2f} bits'
f'\n avg ideal jump distance: {self.alpha_expected:20.0f} {math.log2(self.alpha_expected):.2f} bits'
f'\n avg real jump distance: {self.alpha_real:20.0f} {math.log2(self.alpha_real):.2f} bits'
)
batch_jp = self.batch_jp
num_ops = 0
dp_mask = (1 << dp) - 1
for idx in range(herd_size):
self.create_kangaroo(0, idx, self.v)
self.create_kangaroo(1, idx, self.v)
self.num_created += 2
tames, t_dist = self.tames, self.t_dist
wilds, w_dist = self.wilds, self.w_dist
n = self.n
start_time = time.time()
last_p_time = 0
while True:
for idx in range(herd_size):
k, born = self.check_col(0, idx, dp_mask)
self.num_created += born
if k:
return k, num_ops, len(self.hashmap)
jump_idx = tames[idx].x % n
# tames[idx] = Group.add(tames[idx], jump_points[d]) # un-batched addition
batch_jp[idx] = self.jump_points[jump_idx]
t_dist[idx] += self.jump_distances[jump_idx]
Group.batch_add(tames, batch_jp)
num_ops += len(tames)
for idx in range(herd_size):
k, born = self.check_col(1, idx, dp_mask)
self.num_created += born
if k:
return k, num_ops, len(self.hashmap)
jump_idx = wilds[idx].x % n
# wilds[idx] = Group.add(wilds[idx], jump_points[d]) # un-batched addition
batch_jp[idx] = self.jump_points[jump_idx]
w_dist[idx] += self.jump_distances[jump_idx]
Group.batch_add(wilds, batch_jp)
num_ops += len(wilds)
total_time = time.time() - start_time
if total_time - last_p_time > 2:
last_p_time = total_time
print(f'Ops: {num_ops} Table size: {len(self.hashmap)} Speed: {num_ops / total_time:.0f} ops/s')
def benchmark_kangaroo(bits: int, dp: int = 0, herd_size: int = 128, num_runs=100):
k1, k2 = 1, 1 << bits # k interval = [1, 2**n]
total_group_add = 0 # group operations (e.g. P + Q)
total_group_mul = 0 # point scalar ops (e.g. [k] * P)
total_size = 0
total_time = 0
tr = TrueRandom(k2, 256, k1)
kangaroo = Kangaroo(k1, k2, dp, herd_size, verify=True)
for i in range(num_runs):
pk = tr.get_next()
print(f'Solve for {pk}')
target_point = Group.mul(Group.G, pk)
start_time = time.monotonic()
k, ops, hashmap_size = kangaroo.solve(target_point)
total_time += time.monotonic() - start_time
found = False
for k_cand in k:
if k_cand == pk:
found = True
break
if not found:
raise Exception(f'BAD solution! {pk} not in {k}')
total_group_mul += kangaroo.num_created
total_group_add += ops
total_size += hashmap_size
ops_per_solve = total_group_add / (i + 1)
dp_ovh = (1 << dp) * herd_size
ops_minus_dp_overhead = ops_per_solve - dp_ovh
print(f'[{i + 1}] AVG Ops: {ops_per_solve:.0f}'
f' ({ops_minus_dp_overhead / math.sqrt(k2 - k1 + 1):.3f} * sqrt(b)'
f' + (dp_ovh = 2**{math.log2(dp_ovh)}))'
f' AVG Stored: {total_size / (i + 1):.0f}'
f' AVG k_crt: {total_group_mul / (i + 1):.0f}'
f' AVG Speed: {total_group_add / total_time:.0f} op/s'
)
def run_puzzle(idx: int, pub_key, dp: int = 0, herd_size: int = 128):
# puzzle #X has (X - 1) unknown bits
k1 = 1 << (idx - 1)
k2 = (k1 << 1) - 1
target_point = Point.uncompress(pub_key)
k = Kangaroo(k1, k2, dp, herd_size, verify=True)
start_time = time.monotonic()
_, ops, hashmap_size = k.solve(target_point)
total_time = time.monotonic() - start_time
print(f'Ops: {ops} Stored: {hashmap_size}'
f'\nSpeed: {ops / total_time:.0f} ops/s'
f'\nFinished in {total_time:.3} s'
)
if __name__ == '__main__':
# run_puzzle(32, '0209c58240e50e3ba3f833c82655e8725c037a2294e14cf5d73a5df8d56159de69',
# herd_size=512)
# run_puzzle(40, '03a2efa402fd5268400c77c20e574ba86409ededee7c4020e4b9f0edbee53de0d4',
# herd_size=512, dp=4)
run_puzzle(48, '0291bee5cf4b14c291c650732faa166040e4c18a14731f9a930c1e87d3ec12debb',
herd_size=1024, dp=6)
# benchmark_kangaroo(32, dp=4, herd_size=512, num_runs=1000)
48 bits finished 3 times faster than expected. Oh well.
Zero randomness used (the only purpose of TrueRandom is to generate random private keys to benchmark).
