hash_grin_pow.py

#!/usr/bin/env python3

import bitarray
from hashlib import blake2b

# POW Constants
BASE_EDGE_BITS = 24
PROOFSIZE = 42;

# https://github.com/mimblewimble/grin/blob/cccaf984936d4792f8b6c39e6b500ad2e3f08817/core/src/pow/types.rs#L314

def hash_pow(proof, nonce_bits):
    bitvec = (nonce_bits*PROOFSIZE) * [0]
    for n, nonce in enumerate(proof):
        for bit in range(0, nonce_bits):
            if nonce & (1 << bit) != 0:
                bitvec[n * nonce_bits + bit] = 1
    ba = bitarray.bitarray(bitvec,  endian='little')
    h = blake2b(digest_size=32)
    h.update(ba)
    return h.hexdigest()

if __name__ == "__main__":
    # Example: Block 1149420
    pow = [86374760,154070018,222282246,242833237,438849293,619616595,699767524,824463679,960080314,1036405980,1089437639,1113708730,1148690094,1175329636,1286909702,1596013578,1636801188,1701402692,1723742869,1728061221,1747385321,1749092119,1831902087,1838767249,1960982891,2242937324,2335872672,2595968733,2622951640,2636225213,2827083503,2895620255,3058609249,3102998739,3165804021,3241357991,3390683027,3694396261,3737229546,3970590467,4038313798,4294675502]
    edge_bits = 32

    h = hash_pow(pow, edge_bits)
    print("Hash: {}".format(h))