4 from electrum import Interface
5 from electrum.bitcoin import Hash, rev_hex, int_to_hex
7 """validate a transaction (SPV)"""
10 i = Interface({'server':'ecdsa.org:50002:s'})
14 encode = lambda x: x[::-1].encode('hex')
15 decode = lambda x: x.decode('hex')[::-1]
18 def merkle_root(merkle_s, target_hash):
19 h = decode(target_hash)
21 is_left = item[0] == 'L'
23 h = Hash( h + decode(item[1:]) )
25 h = Hash( decode(item[1:]) + h )
30 header = int_to_hex(res.get('version'),4) \
31 + rev_hex(res.get('prev_block_hash')) \
32 + rev_hex(res.get('merkle_root')) \
33 + int_to_hex(int(res.get('timestamp')),4) \
34 + int_to_hex(int(res.get('bits')),4) \
35 + int_to_hex(int(res.get('nonce')),4)
36 return rev_hex(Hash(header.decode('hex')).encode('hex'))
39 def verify_tx(tx_hash):
41 res = i.synchronous_get([ ('blockchain.transaction.get_merkle',[tx_hash]) ])[0]
42 assert res.get('merkle_root') == merkle_root(res['merkle'], tx_hash)
43 block_height = res.get('block_height')
47 for height in range(block_height-10,block_height+10):
48 headers_requests.append( ('blockchain.block.get_header',[height]) )
49 res = i.synchronous_get(headers_requests)
53 if _hash: assert _hash == header.get('prev_block_hash')
54 _hash = hash_header(header)
56 if height==block_height:
57 assert header.get('merkle_root') == res.get('merkle_root')
63 tx = '587430e52af2cec98b3fd543083469ffa7a5f5dd2bd569898a7897a64e2eb031'