electrum-bitcoinprivate/scripts/validate_tx

#!/usr/bin/env python

import sys, hashlib
from electrum import Interface
from electrum.bitcoin import Hash, rev_hex, int_to_hex

"""validate a transaction (SPV)"""


i = Interface({'server':'ecdsa.org:50002:s'})
i.start()


encode = lambda x: x[::-1].encode('hex')
decode = lambda x: x.decode('hex')[::-1]


def merkle_root(merkle_s, target_hash):
    h = decode(target_hash)
    for item in merkle_s:
        is_left = item[0] == 'L'
        if is_left:
            h = Hash( h + decode(item[1:]) )
        else:
            h = Hash( decode(item[1:]) + h )
    return encode(h)


def hash_header(res):
    header = int_to_hex(res.get('version'),4) \
        + rev_hex(res.get('prev_block_hash')) \
        + rev_hex(res.get('merkle_root')) \
        + int_to_hex(int(res.get('timestamp')),4) \
        + int_to_hex(int(res.get('bits')),4) \
        + int_to_hex(int(res.get('nonce')),4)
    return rev_hex(Hash(header.decode('hex')).encode('hex'))


def verify_tx(tx_hash):
    
    res = i.synchronous_get([ ('blockchain.transaction.get_merkle',[tx_hash]) ])[0]
    assert res.get('merkle_root') == merkle_root(res['merkle'], tx_hash)
    block_height = res.get('block_height')
    print block_height

    headers_requests = []
    for height in range(block_height-10,block_height+10):
        headers_requests.append( ('blockchain.block.get_header',[height]) )
    res = i.synchronous_get(headers_requests)

    _hash = None
    for header in res:
        if _hash: assert _hash == header.get('prev_block_hash')
        _hash = hash_header(header)
        print _hash
        if height==block_height:
            assert header.get('merkle_root') == res.get('merkle_root')


try:
    tx = sys.argv[1]
except:
    tx = '587430e52af2cec98b3fd543083469ffa7a5f5dd2bd569898a7897a64e2eb031'

verify_tx(tx)