4 from electrum import Interface
6 """validate a transaction (SPV)"""
9 Hash = lambda x: hashlib.sha256(hashlib.sha256(x).digest()).digest()
12 return s.decode('hex')[::-1].encode('hex')
14 def int_to_hex(i, length=1):
15 s = hex(i)[2:].rstrip('L')
16 s = "0"*(2*length - len(s)) + s
20 i = Interface({'server':'ecdsa.org:50002:s'})
24 def merkle_root(merkle):
26 merkle = map (lambda tx_hash: tx_hash.decode('hex')[::-1], merkle)
27 while len(merkle) != 1:
28 if len(merkle)%2: merkle.append( merkle[-1] )
31 n.append( Hash( merkle[0] + merkle[1] ) )
36 return merkle[0][::-1].encode('hex')
40 header = int_to_hex(res.get('version'),4) \
41 + rev_hex(res.get('prev_block_hash')) \
42 + rev_hex(res.get('merkle_root')) \
43 + int_to_hex(int(res.get('timestamp')),4) \
44 + int_to_hex(int(res.get('bits')),4) \
45 + int_to_hex(int(res.get('nonce')),4)
46 return rev_hex(Hash(header.decode('hex')).encode('hex'))
49 def verify_tx(tx_hash):
51 res = i.synchronous_get([ ('blockchain.transaction.get_merkle',[tx_hash]) ])[0]
52 assert tx_hash in res.get('merkle')
53 assert res.get('merkle_root') == merkle_root(res['merkle'])
54 block_height = res.get('block_height')
58 for height in range(block_height-10,block_height+10):
59 headers_requests.append( ('blockchain.block.get_header',[height]) )
60 res = i.synchronous_get(headers_requests)
64 if _hash: assert _hash == header.get('prev_block_hash')
65 _hash = hash_header(header)
67 if height==block_height:
68 assert header.get('merkle_root') == res.get('merkle_root')
75 tx = '587430e52af2cec98b3fd543083469ffa7a5f5dd2bd569898a7897a64e2eb031'