Python으로 비트코인 블록체인 블록헤더 해쉬 계산해보기

Python으로 블록헤더 해쉬 계산해보기

 

1. 계산해볼 블록 선정(예시, 블록 높이 734206)

 

 

2. 계산 공식

 

3. 파이썬 코드

 

3-1. block header에 들어갈 변수들(version, previous blockhash, merkleroot, time, bits, nonce)로 구조체 만들기

# block 734206 header
block_header={
    'ver': '0x2000e004',    # 4 bytes
    'prev_block':'0000000000000000000914331e5d52001a51ce23b4d176b4adbbdba9aac57663',    # 32 bytes
    'mrkl_root':'c6c565adffee226711d676ffee5fca583f5e5c4a5b93e6f03804386643f024bc',     # 32 bytes
    'time' : '2022-04-30 15:42:07',  # 4 bytes
    'bits' : '0x17097275',  # 4 bytes
    'nonce' : '0x3e1cb67c'  # 4 bytes
}   # total 80 bytes
 

 

3-2. string, int, datetime으로 된 각 값들을 hex값으로 convert

[INPUT]

##########################
# format convert to hex
##########################
from datetime import datetime
import time
import binascii
 
# reverse hex
block_header['ver'] = binascii.unhexlify(block_header['ver'][2:])[::-1].hex()
block_header['prev_block'] = binascii.unhexlify(block_header['prev_block'])[::-1].hex()
block_header['mrkl_root'] = binascii.unhexlify(block_header['mrkl_root'])[::-1].hex()
block_header['bits'] = binascii.unhexlify(block_header['bits'][2:])[::-1].hex()
block_header['nonce'] = binascii.unhexlify(block_header['nonce'][2:])[::-1].hex()
# time -> unix epoch -> hex
# and reverse hex
block_header['time'] = binascii.unhexlify(hex(int(time.mktime(\
    datetime.strptime(block_header['time'], '%Y-%m-%d %H:%M:%S').timetuple())))[2:])[::-1].hex()
 
from pprint import pprint
pprint(block_header)

[OUTPUT]

{'bits': '75720917',
 'mrkl_root': 'bc24f04366380438f0e6935b4a5c5e3f58ca5feeff76d6116722eeffad65c5c6',
 'nonce': '7cb61c3e',
 'prev_block': '6376c5aaa9dbbbadb476d1b423ce511a00525d1e331409000000000000000000',
 'time': '3fda6c62',
 'ver': '04e00020'}

 

3-3. header 직렬화(serialized) 및 double hashing

[INPUT]

##########################################################################
# serialized(80 bytes) -> double hashing(32 bytes) -> reverse -> get ID
##########################################################################
 
# serialized(80 bytes)
header = block_header['ver']+block_header['prev_block']+\
    block_header['mrkl_root']+str(block_header['time'])+block_header['bits']+block_header['nonce']
 
print(header)
print('size = ',len(header)*4,'bits')
header_bin = binascii.a2b_hex(header)
 
 
# double hashing(32 bytes)
import hashlib
import codecs
hash256 = hashlib.sha256(hashlib.sha256(header_bin).digest()).digest()
id_block_header_hash = codecs.encode(hash256[::-1],'hex').decode('utf-8')
print(id_block_header_hash)

[OUTPUT]

04e000206376c5aaa9dbbbadb476d1b423ce511a00525d1e331409000000000000000000bc24f04366380438f0e6935b4a5c5e3f58ca5feeff76d6116722eeffad65c5c63fda6c62757209177cb61c3e
size =  640 bits
00000000000000000008cd76babc05dc40cf177f790cbec0f79a54459657c2ae

 

4. 3-3에서 나온 id_block_header_hash와 734206높이의 block header 비교