|
| 1 | +#!/usr/bin/env python3 |
| 2 | + |
| 3 | +import hashlib |
| 4 | +import json |
| 5 | +import sys |
| 6 | + |
| 7 | +## Graypaper conforming implementation of the binary tree used for the state merklization (Appendix D) |
| 8 | +## Based on GP 0.2.2 |
| 9 | + |
| 10 | +# Blake2b-256 |
| 11 | +def hash(data): |
| 12 | + return hashlib.blake2b(data, digest_size=32).digest() |
| 13 | + |
| 14 | +# GP (286) |
| 15 | +def branch(l, r): |
| 16 | + assert len(l) == 32 |
| 17 | + assert len(r) == 32 |
| 18 | + head = l[0] & 0xfe |
| 19 | + return bytes([head]) + l[1:] + r |
| 20 | + |
| 21 | +# GP (287) |
| 22 | +def leaf(k, v): |
| 23 | + if len(v) <= 32: |
| 24 | + head = 0b01 | (len(v) << 2) |
| 25 | + return bytes([head]) + k[:-1] + v + ((32 - len(v)) * b'\0') |
| 26 | + head = 0b11 |
| 27 | + return bytes([head]) + k[:-1] + hash(v) |
| 28 | + |
| 29 | +def bit(k, i): |
| 30 | + return (k[i >> 3] & (1 << (i & 7))) != 0 |
| 31 | + |
| 32 | +# GP (289) |
| 33 | +def merkle(kvs, i=0): |
| 34 | + if not kvs: |
| 35 | + return 32 * b'\0' |
| 36 | + if len(kvs) == 1: |
| 37 | + encoded = leaf(*kvs[0]) |
| 38 | + else: |
| 39 | + l = [] |
| 40 | + r = [] |
| 41 | + for k, v in kvs: |
| 42 | + if bit(k, i): |
| 43 | + r.append((k, v)) |
| 44 | + else: |
| 45 | + l.append((k, v)) |
| 46 | + encoded = branch(merkle(l, i + 1), merkle(r, i + 1)) |
| 47 | + assert len(encoded) == 64 |
| 48 | + return hash(encoded) |
| 49 | + |
| 50 | +## Random number generation |
| 51 | + |
| 52 | +def wrap_64(x): |
| 53 | + return x & ((1 << 64) - 1) |
| 54 | + |
| 55 | +def rol_64(x, y): |
| 56 | + return wrap_64(x << y) | (x >> (64 - y)) |
| 57 | + |
| 58 | +class Rng: |
| 59 | + '''Xoshiro256** RNG. |
| 60 | +
|
| 61 | + Matches Xoshiro256StarStar in crates.io's rand_xoshiro 0.6.0 with rand 0.8.5.''' |
| 62 | + |
| 63 | + def __init__(self, seed): |
| 64 | + def split_mix_64(): |
| 65 | + nonlocal seed |
| 66 | + seed = wrap_64(seed + 0x9e3779b97f4a7c15) |
| 67 | + res = wrap_64((seed ^ (seed >> 30)) * 0xbf58476d1ce4e5b9) |
| 68 | + res = wrap_64((res ^ (res >> 27)) * 0x94d049bb133111eb) |
| 69 | + return res ^ (res >> 31) |
| 70 | + |
| 71 | + self.__s = [split_mix_64() for i in range(4)] |
| 72 | + |
| 73 | + def next_64(self): |
| 74 | + res = wrap_64(rol_64(wrap_64(self.__s[1] * 5), 7) * 9) |
| 75 | + |
| 76 | + t = wrap_64(self.__s[1] << 17) |
| 77 | + |
| 78 | + self.__s[2] ^= self.__s[0] |
| 79 | + self.__s[3] ^= self.__s[1] |
| 80 | + self.__s[1] ^= self.__s[2] |
| 81 | + self.__s[0] ^= self.__s[3] |
| 82 | + |
| 83 | + self.__s[2] ^= t |
| 84 | + |
| 85 | + self.__s[3] = rol_64(self.__s[3], 45) |
| 86 | + |
| 87 | + return res |
| 88 | + |
| 89 | + def next_32(self): |
| 90 | + return self.next_64() >> 32 |
| 91 | + |
| 92 | + def bytes(self, num): |
| 93 | + data = bytearray() |
| 94 | + while len(data) < num: |
| 95 | + if (num - len(data)) > 4: |
| 96 | + data.extend(self.next_64().to_bytes(8, byteorder='little')) |
| 97 | + else: |
| 98 | + data.extend(self.next_32().to_bytes(4, byteorder='little')) |
| 99 | + return bytes(data[:num]) |
| 100 | + |
| 101 | + def range_64(self, low, high): |
| 102 | + assert 0 <= low <= high < (1 << 64) |
| 103 | + |
| 104 | + r = high - low + 1 |
| 105 | + if r == (1 << 64): |
| 106 | + assert low == 0 |
| 107 | + return self.next_64() |
| 108 | + |
| 109 | + zone = r << (64 - r.bit_length()) |
| 110 | + while True: |
| 111 | + x = self.next_64() * r |
| 112 | + if wrap_64(x) < zone: |
| 113 | + return low + (x >> 64) |
| 114 | + |
| 115 | +## Test vector generation |
| 116 | + |
| 117 | +def random_key(rng): |
| 118 | + return rng.bytes(32) |
| 119 | + |
| 120 | +def random_value(rng, size=None): |
| 121 | + if size is None: |
| 122 | + size = rng.range_64(0, 64) |
| 123 | + return rng.bytes(size) |
| 124 | + |
| 125 | +def inputs(): |
| 126 | + rng = Rng(42) |
| 127 | + |
| 128 | + yield [] |
| 129 | + yield [(random_key(rng), b'')] |
| 130 | + yield [(random_key(rng), random_value(rng, 1))] |
| 131 | + yield [(random_key(rng), random_value(rng, 32))] |
| 132 | + yield [(random_key(rng), random_value(rng, 33))] |
| 133 | + yield [(random_key(rng), random_value(rng, 60))] |
| 134 | + |
| 135 | + k1 = random_key(rng) |
| 136 | + k2 = bytes([k1[0] ^ 1]) + k1[1:] |
| 137 | + yield [(k1, random_value(rng)), (k2, random_value(rng))] |
| 138 | + |
| 139 | + k1 = random_key(rng) |
| 140 | + k2 = k1[:1] + bytes([k1[1] ^ 1]) + k1[2:] |
| 141 | + yield [(k1, random_value(rng)), (k2, random_value(rng))] |
| 142 | + |
| 143 | + yield [(random_key(rng), random_value(rng)) for i in range(2)] |
| 144 | + yield [(random_key(rng), random_value(rng)) for i in range(5)] |
| 145 | + yield [(random_key(rng), random_value(rng)) for i in range(10)] |
| 146 | + |
| 147 | +def hex(data): |
| 148 | + return ''.join(f'{x:02x}' for x in data) |
| 149 | + |
| 150 | +def test_vectors(): |
| 151 | + for kvs in inputs(): |
| 152 | + yield { |
| 153 | + 'input': {hex(k): hex(v) for k, v in kvs}, |
| 154 | + 'output': hex(merkle(kvs)), |
| 155 | + } |
| 156 | + |
| 157 | +def main(): |
| 158 | + json.dump(list(test_vectors()), sys.stdout, indent=' ') |
| 159 | + |
| 160 | +main() |
0 commit comments