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92 lines
3.7 KiB
92 lines
3.7 KiB
#!/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_height>0 and 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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