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94 lines
2.4 KiB
94 lines
2.4 KiB
#!/usr/bin/env python |
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import sys, hashlib |
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from electrum import Interface |
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"""validate a transaction (SPV)""" |
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Hash = lambda x: hashlib.sha256(hashlib.sha256(x).digest()).digest() |
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def rev_hex(s): |
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return s.decode('hex')[::-1].encode('hex') |
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def int_to_hex(i, length=1): |
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s = hex(i)[2:].rstrip('L') |
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s = "0"*(2*length - len(s)) + s |
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return rev_hex(s) |
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i = Interface({'server':'ecdsa.org:50002:s'}) |
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i.start() |
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def get_header(i, block_height): |
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i.send([('blockchain.block.get_header',[block_height])]) |
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while True: |
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r = i.responses.get(True, 100000000000) |
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method = r.get('method') |
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if method == 'blockchain.block.get_header': |
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break |
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return r.get('result') |
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def get_merkle(i, tx_hash): |
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i.send([('blockchain.transaction.get_merkle',[tx_hash])]) |
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while True: |
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r = i.responses.get(True, 100000000000) |
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method = r.get('method') |
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if method == 'blockchain.transaction.get_merkle': |
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break |
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return r.get('result') |
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def merkle_root(merkle): |
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merkle = map (lambda tx_hash: tx_hash.decode('hex')[::-1], merkle) |
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while len(merkle) != 1: |
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if len(merkle)%2: merkle.append( merkle[-1] ) |
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n = [] |
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while merkle: |
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n.append( Hash( merkle[0] + merkle[1] ) ) |
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merkle = merkle[2:] |
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merkle = n |
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return merkle[0][::-1].encode('hex') |
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def hash_header(res): |
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header = int_to_hex(res.get('version'),4) \ |
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+ rev_hex(res.get('prev_block_hash')) \ |
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+ rev_hex(res.get('merkle_root')) \ |
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+ int_to_hex(int(res.get('timestamp')),4) \ |
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+ int_to_hex(int(res.get('bits')),4) \ |
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+ int_to_hex(int(res.get('nonce')),4) |
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return rev_hex(Hash(header.decode('hex')).encode('hex')) |
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def verify_tx(tx_hash): |
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res = get_merkle(i, tx_hash) |
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assert tx_hash in res.get('merkle') |
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assert res.get('merkle_root') == merkle_root(res['merkle']) |
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block_height = res.get('block_height') |
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_hash = None |
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for height in range(block_height-10,block_height+10): |
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header = get_header(i, height) |
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if _hash: assert _hash == header.get('prev_block_hash') |
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_hash = hash_header(header) |
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#print _hash |
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if height==block_height: |
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assert header.get('merkle_root') == res.get('merkle_root') |
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try: |
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tx = sys.argv[1] |
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except: |
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tx = '587430e52af2cec98b3fd543083469ffa7a5f5dd2bd569898a7897a64e2eb031' |
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verify_tx(tx) |
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