scripts/validate_tx

   1 #!/usr/bin/env python
   2
   3 import sys, hashlib
   4 from electrum import Interface
   5 from electrum.bitcoin import Hash, rev_hex, int_to_hex, hash_encode, hash_decode
   6
   7 """validate a transaction (SPV)"""
   8
   9 i = Interface({'server':'ecdsa.org:50002:s'})
  10 i.start()
  11
  12
  13 def hash_merkle_root(merkle_s, target_hash, pos):
  14     h = hash_decode(target_hash)
  15     for i in range(len(merkle_s)):
  16         item = merkle_s[i]
  17         h = Hash( hash_decode(item) + h ) if ((pos >> i) & 1) else Hash( h + hash_decode(item) )
  18     return hash_encode(h)
  19
  20
  21 def hash_header(res):
  22     header = int_to_hex(res.get('version'),4) \
  23         + rev_hex(res.get('prev_block_hash')) \
  24         + rev_hex(res.get('merkle_root')) \
  25         + int_to_hex(int(res.get('timestamp')),4) \
  26         + int_to_hex(int(res.get('bits')),4) \
  27         + int_to_hex(int(res.get('nonce')),4)
  28     return rev_hex(Hash(header.decode('hex')).encode('hex'))
  29
  30
  31 def verify_tx(tx_hash):
  32
  33     res = i.synchronous_get([ ('blockchain.transaction.get_merkle',[tx_hash]) ])[0]
  34     raw_tx = i.synchronous_get([ ('blockchain.transaction.get',[tx_hash, res['block_height']]) ])[0]
  35     assert hash_encode(Hash(raw_tx.decode('hex'))) == tx_hash
  36
  37     merkle_root = hash_merkle_root(res['merkle'], tx_hash, res['pos'])
  38     tx_height = res.get('block_height')
  39     headers_requests = []
  40     for height in range(tx_height-10,tx_height+10):
  41         headers_requests.append( ('blockchain.block.get_header',[height]) )
  42     headers = i.synchronous_get(headers_requests)
  43     _hash = None
  44     for header in headers:
  45         if _hash: assert _hash == header.get('prev_block_hash')
  46         _hash = hash_header(header)
  47         height = header.get('block_height')
  48         if height==tx_height:
  49             assert header.get('merkle_root') == merkle_root
  50             print height, _hash, '*'
  51         else:
  52             print height, _hash
  53
  54 try:
  55     tx = sys.argv[1]
  56 except:
  57     tx = '587430e52af2cec98b3fd543083469ffa7a5f5dd2bd569898a7897a64e2eb031'
  58
  59 verify_tx(tx)
  60