secp256k1 #920

verify.py

from ec import *

import hashlib

def accumulate(m, h):
    if h.infinity:
        m.update(b'\0')
    else:
        m.update(h.encode_uncompressed())

# Copied from PR
expected = [
    0xe4, 0x71, 0x1b, 0x4d, 0x14, 0x1e, 0x68, 0x48,
    0xb7, 0xaf, 0x47, 0x2b, 0x4c, 0xd2, 0x04, 0x14,
    0x3a, 0x75, 0x87, 0x60, 0x1a, 0xf9, 0x63, 0x60,
    0xd0, 0xcb, 0x1f, 0xaa, 0x85, 0x9a, 0xb7, 0xb4
]

# table[i] = 2^i * h
table = []
h = G
for i in range(256):
    table.append(h)
    h = 2 * h

m = hashlib.sha256()
h = INFINITY
for i in range(37):
    accumulate(m, h)
    accumulate(m, -h)
    h += G

for i in range(256):
    # h = 2^i * G
    h = table[i]
    delta = 2 * h
    for j in range(1, 256, 2):
        accumulate(m, h)
        h = delta + h

assert list(m.digest()) == expected