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94 lines
2.3 KiB
94 lines
2.3 KiB
12 years ago
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#!/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 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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