93 lines
3.7 KiB
Python
93 lines
3.7 KiB
Python
#!/usr/bin/env python
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#
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# Electrum - Lightweight Bitcoin Client
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# Copyright (c) 2012 Thomas Voegtlin
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#
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# Permission is hereby granted, free of charge, to any person
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# obtaining a copy of this software and associated documentation files
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# (the "Software"), to deal in the Software without restriction,
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# including without limitation the rights to use, copy, modify, merge,
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# publish, distribute, sublicense, and/or sell copies of the Software,
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# and to permit persons to whom the Software is furnished to do so,
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# subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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from util import ThreadJob
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from bitcoin import *
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class SPV(ThreadJob):
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""" Simple Payment Verification """
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def __init__(self, network, wallet):
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self.wallet = wallet
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self.network = network
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# Keyed by tx hash. Value is None if the merkle branch was
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# requested, and the merkle root once it has been verified
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self.merkle_roots = {}
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def run(self):
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lh = self.network.get_local_height()
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unverified = self.wallet.get_unverified_txs()
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for tx_hash, tx_height in unverified.items():
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# do not request merkle branch before headers are available
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if tx_hash not in self.merkle_roots and tx_height <= lh:
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request = ('blockchain.transaction.get_merkle',
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[tx_hash, tx_height])
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self.network.send([request], self.verify_merkle)
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self.print_error('requested merkle', tx_hash)
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self.merkle_roots[tx_hash] = None
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def verify_merkle(self, r):
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if r.get('error'):
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self.print_error('received an error:', r)
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return
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params = r['params']
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merkle = r['result']
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# Verify the hash of the server-provided merkle branch to a
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# transaction matches the merkle root of its block
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tx_hash = params[0]
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tx_height = merkle.get('block_height')
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pos = merkle.get('pos')
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merkle_root = self.hash_merkle_root(merkle['merkle'], tx_hash, pos)
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header = self.network.get_header(tx_height)
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if not header or header.get('merkle_root') != merkle_root:
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# FIXME: we should make a fresh connection to a server to
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# recover from this, as this TX will now never verify
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self.print_error("merkle verification failed for", tx_hash)
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return
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# we passed all the tests
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self.merkle_roots[tx_hash] = merkle_root
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self.print_error("verified %s" % tx_hash)
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self.wallet.add_verified_tx(tx_hash, (tx_height, header.get('timestamp'), pos))
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def hash_merkle_root(self, merkle_s, target_hash, pos):
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h = hash_decode(target_hash)
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for i in range(len(merkle_s)):
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item = merkle_s[i]
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h = Hash( hash_decode(item) + h ) if ((pos >> i) & 1) else Hash( h + hash_decode(item) )
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return hash_encode(h)
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def undo_verifications(self, height):
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tx_hashes = self.wallet.undo_verifications(height)
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for tx_hash in tx_hashes:
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self.print_error("redoing", tx_hash)
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self.merkle_roots.pop(tx_hash, None)
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