4 from electrum import Interface
5 from electrum.bitcoin import Hash, rev_hex, int_to_hex
7 """validate a transaction (SPV)"""
9 i = Interface({'server':'ecdsa.org:50002:s'})
12 encode = lambda x: x[::-1].encode('hex')
13 decode = lambda x: x.decode('hex')[::-1]
16 def do_merkle_root(merkle_s, target_hash):
17 h = decode(target_hash)
19 is_left = item[0] == 'L'
20 h = Hash( h + decode(item[1:]) ) if is_left else Hash( decode(item[1:]) + h )
25 header = int_to_hex(res.get('version'),4) \
26 + rev_hex(res.get('prev_block_hash')) \
27 + rev_hex(res.get('merkle_root')) \
28 + int_to_hex(int(res.get('timestamp')),4) \
29 + int_to_hex(int(res.get('bits')),4) \
30 + int_to_hex(int(res.get('nonce')),4)
31 return rev_hex(Hash(header.decode('hex')).encode('hex'))
34 def verify_tx(tx_hash):
35 res = i.synchronous_get([ ('blockchain.transaction.get_merkle',[tx_hash]) ])[0]
36 merkle_root = do_merkle_root(res['merkle'], tx_hash)
37 tx_height = res.get('block_height')
39 for height in range(tx_height-10,tx_height+10):
40 headers_requests.append( ('blockchain.block.get_header',[height]) )
41 headers = i.synchronous_get(headers_requests)
43 for header in headers:
44 if _hash: assert _hash == header.get('prev_block_hash')
45 _hash = hash_header(header)
46 height = header.get('block_height')
48 assert header.get('merkle_root') == merkle_root
49 print height, _hash, '*'
56 tx = '587430e52af2cec98b3fd543083469ffa7a5f5dd2bd569898a7897a64e2eb031'