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85 lines
3.3 KiB
85 lines
3.3 KiB
#!/usr/bin/env python |
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# |
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# Electrum - lightweight Bitcoin client |
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# Copyright (C) 2012 thomasv@ecdsa.org |
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# |
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# This program is free software: you can redistribute it and/or modify |
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# it under the terms of the GNU General Public License as published by |
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# the Free Software Foundation, either version 3 of the License, or |
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# (at your option) any later version. |
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# |
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# This program is distributed in the hope that it will be useful, |
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# but WITHOUT ANY WARRANTY; without even the implied warranty of |
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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# GNU General Public License for more details. |
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# |
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# You should have received a copy of the GNU General Public License |
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# along with this program. If not, see <http://www.gnu.org/licenses/>. |
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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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