import sys, hashlib
from electrum import Interface
+from electrum.bitcoin import Hash, rev_hex, int_to_hex
"""validate a transaction (SPV)"""
-
-Hash = lambda x: hashlib.sha256(hashlib.sha256(x).digest()).digest()
-
-def rev_hex(s):
- return s.decode('hex')[::-1].encode('hex')
-
-def int_to_hex(i, length=1):
- s = hex(i)[2:].rstrip('L')
- s = "0"*(2*length - len(s)) + s
- return rev_hex(s)
-
-
i = Interface({'server':'ecdsa.org:50002:s'})
i.start()
-
-def get_header(i, block_height):
- i.send([('blockchain.block.get_header',[block_height])])
- while True:
- r = i.responses.get(True, 100000000000)
- method = r.get('method')
- if method == 'blockchain.block.get_header':
- break
- return r.get('result')
-
+encode = lambda x: x[::-1].encode('hex')
+decode = lambda x: x.decode('hex')[::-1]
-def get_merkle(i, tx_hash):
-
- i.send([('blockchain.transaction.get_merkle',[tx_hash])])
- while True:
- r = i.responses.get(True, 100000000000)
- method = r.get('method')
- if method == 'blockchain.transaction.get_merkle':
- break
-
- return r.get('result')
-
-
-def merkle_root(merkle):
-
- merkle = map (lambda tx_hash: tx_hash.decode('hex')[::-1], merkle)
- while len(merkle) != 1:
- if len(merkle)%2: merkle.append( merkle[-1] )
- n = []
- while merkle:
- n.append( Hash( merkle[0] + merkle[1] ) )
- merkle = merkle[2:]
-
- merkle = n
-
- return merkle[0][::-1].encode('hex')
+def do_merkle_root(merkle_s, target_hash):
+ h = decode(target_hash)
+ for item in merkle_s:
+ is_left = item[0] == 'L'
+ h = Hash( h + decode(item[1:]) ) if is_left else Hash( decode(item[1:]) + h )
+ return encode(h)
def hash_header(res):
def verify_tx(tx_hash):
- res = get_merkle(i, tx_hash)
- assert tx_hash in res.get('merkle')
- assert res.get('merkle_root') == merkle_root(res['merkle'])
- block_height = res.get('block_height')
+ res = i.synchronous_get([ ('blockchain.transaction.get_merkle',[tx_hash]) ])[0]
+ merkle_root = do_merkle_root(res['merkle'], tx_hash)
+ tx_height = res.get('block_height')
+ headers_requests = []
+ for height in range(tx_height-10,tx_height+10):
+ headers_requests.append( ('blockchain.block.get_header',[height]) )
+ headers = i.synchronous_get(headers_requests)
_hash = None
- for height in range(block_height-10,block_height+10):
- header = get_header(i, height)
+ for header in headers:
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')
-
-
+ height = header.get('block_height')
+ if height==tx_height:
+ assert header.get('merkle_root') == merkle_root
+ print height, _hash, '*'
+ else:
+ print height, _hash
try:
tx = sys.argv[1]