sapio_bitcoin/util/
merkleblock.rs

1// Rust Bitcoin Library
2// Written by
3//   John L. Jegutanis
4//
5// To the extent possible under law, the author(s) have dedicated all
6// copyright and related and neighboring rights to this software to
7// the public domain worldwide. This software is distributed without
8// any warranty.
9//
10// You should have received a copy of the CC0 Public Domain Dedication
11// along with this software.
12// If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.
13//
14//
15// This code was translated from merkleblock.h, merkleblock.cpp and pmt_tests.cpp
16// Copyright (c) 2009-2010 Satoshi Nakamoto
17// Copyright (c) 2009-2018 The Bitcoin Core developers
18// Distributed under the MIT software license, see the accompanying
19// file COPYING or http://www.opensource.org/licenses/mit-license.php.
20
21//! Merkle Block and Partial Merkle Tree.
22//!
23//! Support proofs that transaction(s) belong to a block.
24//!
25//! # Examples
26//!
27//! ```rust
28//! use bitcoin::hash_types::Txid;
29//! use bitcoin::hashes::hex::FromHex;
30//! use bitcoin::{Block, MerkleBlock};
31//!
32//! // Get the proof from a bitcoind by running in the terminal:
33//! // $ TXID="5a4ebf66822b0b2d56bd9dc64ece0bc38ee7844a23ff1d7320a88c5fdb2ad3e2"
34//! // $ bitcoin-cli gettxoutproof [\"$TXID\"]
35//! let mb_bytes = Vec::from_hex("01000000ba8b9cda965dd8e536670f9ddec10e53aab14b20bacad27b913719\
36//!     0000000000190760b278fe7b8565fda3b968b918d5fd997f993b23674c0af3b6fde300b38f33a5914ce6ed5b\
37//!     1b01e32f570200000002252bf9d75c4f481ebb6278d708257d1f12beb6dd30301d26c623f789b2ba6fc0e2d3\
38//!     2adb5f8ca820731dff234a84e78ec30bce4ec69dbd562d0b2b8266bf4e5a0105").unwrap();
39//! let mb: MerkleBlock = bitcoin::consensus::deserialize(&mb_bytes).unwrap();
40//!
41//! // Authenticate and extract matched transaction ids
42//! let mut matches: Vec<Txid> = vec![];
43//! let mut index: Vec<u32> = vec![];
44//! assert!(mb.extract_matches(&mut matches, &mut index).is_ok());
45//! assert_eq!(1, matches.len());
46//! assert_eq!(
47//!     Txid::from_hex(
48//!         "5a4ebf66822b0b2d56bd9dc64ece0bc38ee7844a23ff1d7320a88c5fdb2ad3e2").unwrap(),
49//!     matches[0]
50//! );
51//! assert_eq!(1, index.len());
52//! assert_eq!(1, index[0]);
53//! ```
54
55use prelude::*;
56
57use io;
58
59use hashes::Hash;
60use hash_types::{Txid, TxMerkleNode};
61
62use blockdata::transaction::Transaction;
63use blockdata::constants::{MAX_BLOCK_WEIGHT, MIN_TRANSACTION_WEIGHT};
64use consensus::encode::{self, Decodable, Encodable};
65use util::merkleblock::MerkleBlockError::*;
66use {Block, BlockHeader};
67
68/// An error when verifying the merkle block
69#[derive(Clone, PartialEq, Eq, Debug)]
70pub enum MerkleBlockError {
71    /// When header merkle root don't match to the root calculated from the partial merkle tree
72    MerkleRootMismatch,
73    /// When partial merkle tree contains no transactions
74    NoTransactions,
75    /// When there are too many transactions
76    TooManyTransactions,
77    /// General format error
78    BadFormat(String),
79}
80
81/// Data structure that represents a partial merkle tree.
82///
83/// It represents a subset of the txid's of a known block, in a way that
84/// allows recovery of the list of txid's and the merkle root, in an
85/// authenticated way.
86///
87/// The encoding works as follows: we traverse the tree in depth-first order,
88/// storing a bit for each traversed node, signifying whether the node is the
89/// parent of at least one matched leaf txid (or a matched txid itself). In
90/// case we are at the leaf level, or this bit is 0, its merkle node hash is
91/// stored, and its children are not explored further. Otherwise, no hash is
92/// stored, but we recurse into both (or the only) child branch. During
93/// decoding, the same depth-first traversal is performed, consuming bits and
94/// hashes as they written during encoding.
95///
96/// The serialization is fixed and provides a hard guarantee about the
97/// encoded size:
98///
99///   SIZE <= 10 + ceil(32.25*N)
100///
101/// Where N represents the number of leaf nodes of the partial tree. N itself
102/// is bounded by:
103///
104///   N <= total_transactions
105///   N <= 1 + matched_transactions*tree_height
106///
107/// The serialization format:
108///  - uint32     total_transactions (4 bytes)
109///  - varint     number of hashes   (1-3 bytes)
110///  - uint256[]  hashes in depth-first order (<= 32*N bytes)
111///  - varint     number of bytes of flag bits (1-3 bytes)
112///  - byte[]     flag bits, packed per 8 in a byte, least significant bit first (<= 2*N-1 bits)
113/// The size constraints follow from this.
114#[derive(PartialEq, Eq, Clone, Debug)]
115pub struct PartialMerkleTree {
116    /// The total number of transactions in the block
117    num_transactions: u32,
118    /// node-is-parent-of-matched-txid bits
119    bits: Vec<bool>,
120    /// Transaction ids and internal hashes
121    hashes: Vec<TxMerkleNode>,
122}
123
124impl PartialMerkleTree {
125    /// Construct a partial merkle tree
126    /// The `txids` are the transaction hashes of the block and the `matches` is the contains flags
127    /// wherever a tx hash should be included in the proof.
128    ///
129    /// Panics when `txids` is empty or when `matches` has a different length
130    ///
131    /// # Examples
132    ///
133    /// ```rust
134    /// use bitcoin::hash_types::Txid;
135    /// use bitcoin::hashes::hex::FromHex;
136    /// use bitcoin::util::merkleblock::PartialMerkleTree;
137    ///
138    /// // Block 80000
139    /// let txids: Vec<Txid> = [
140    ///     "c06fbab289f723c6261d3030ddb6be121f7d2508d77862bb1e484f5cd7f92b25",
141    ///     "5a4ebf66822b0b2d56bd9dc64ece0bc38ee7844a23ff1d7320a88c5fdb2ad3e2",
142    /// ]
143    /// .iter()
144    /// .map(|hex| Txid::from_hex(hex).unwrap())
145    /// .collect();
146    ///
147    /// // Select the second transaction
148    /// let matches = vec![false, true];
149    /// let tree = PartialMerkleTree::from_txids(&txids, &matches);
150    /// assert!(tree.extract_matches(&mut vec![], &mut vec![]).is_ok());
151    /// ```
152    pub fn from_txids(txids: &[Txid], matches: &[bool]) -> Self {
153        // We can never have zero txs in a merkle block, we always need the coinbase tx
154        assert_ne!(txids.len(), 0);
155        assert_eq!(txids.len(), matches.len());
156
157        let mut pmt = PartialMerkleTree {
158            num_transactions: txids.len() as u32,
159            bits: Vec::with_capacity(txids.len()),
160            hashes: vec![],
161        };
162        // calculate height of tree
163        let mut height = 0;
164        while pmt.calc_tree_width(height) > 1 {
165            height += 1;
166        }
167        // traverse the partial tree
168        pmt.traverse_and_build(height, 0, txids, matches);
169        pmt
170    }
171
172    /// Extract the matching txid's represented by this partial merkle tree
173    /// and their respective indices within the partial tree.
174    /// returns the merkle root, or error in case of failure
175    pub fn extract_matches(
176        &self,
177        matches: &mut Vec<Txid>,
178        indexes: &mut Vec<u32>,
179    ) -> Result<TxMerkleNode, MerkleBlockError> {
180        matches.clear();
181        indexes.clear();
182        // An empty set will not work
183        if self.num_transactions == 0 {
184            return Err(NoTransactions);
185        };
186        // check for excessively high numbers of transactions
187        if self.num_transactions > MAX_BLOCK_WEIGHT / MIN_TRANSACTION_WEIGHT {
188            return Err(TooManyTransactions);
189        }
190        // there can never be more hashes provided than one for every txid
191        if self.hashes.len() as u32 > self.num_transactions {
192            return Err(BadFormat("Proof contains more hashes than transactions".to_owned()));
193        };
194        // there must be at least one bit per node in the partial tree, and at least one node per hash
195        if self.bits.len() < self.hashes.len() {
196            return Err(BadFormat("Proof contains less bits than hashes".to_owned()));
197        };
198        // calculate height of tree
199        let mut height = 0;
200        while self.calc_tree_width(height) > 1 {
201            height += 1;
202        }
203        // traverse the partial tree
204        let mut bits_used = 0u32;
205        let mut hash_used = 0u32;
206        let hash_merkle_root =
207            self.traverse_and_extract(height, 0, &mut bits_used, &mut hash_used, matches, indexes)?;
208        // Verify that all bits were consumed (except for the padding caused by
209        // serializing it as a byte sequence)
210        if (bits_used + 7) / 8 != (self.bits.len() as u32 + 7) / 8 {
211            return Err(BadFormat("Not all bit were consumed".to_owned()));
212        }
213        // Verify that all hashes were consumed
214        if hash_used != self.hashes.len() as u32 {
215            return Err(BadFormat("Not all hashes were consumed".to_owned()));
216        }
217        Ok(TxMerkleNode::from_inner(hash_merkle_root.into_inner()))
218    }
219
220    /// Helper function to efficiently calculate the number of nodes at given height
221    /// in the merkle tree
222    #[inline]
223    fn calc_tree_width(&self, height: u32) -> u32 {
224        (self.num_transactions + (1 << height) - 1) >> height
225    }
226
227    /// Calculate the hash of a node in the merkle tree (at leaf level: the txid's themselves)
228    fn calc_hash(&self, height: u32, pos: u32, txids: &[Txid]) -> TxMerkleNode {
229        if height == 0 {
230            // Hash at height 0 is the txid itself
231            TxMerkleNode::from_inner(txids[pos as usize].into_inner())
232        } else {
233            // Calculate left hash
234            let left = self.calc_hash(height - 1, pos * 2, txids);
235            // Calculate right hash if not beyond the end of the array - copy left hash otherwise
236            let right = if pos * 2 + 1 < self.calc_tree_width(height - 1) {
237                self.calc_hash(height - 1, pos * 2 + 1, txids)
238            } else {
239                left
240            };
241            // Combine subhashes
242            PartialMerkleTree::parent_hash(left, right)
243        }
244    }
245
246    /// Recursive function that traverses tree nodes, storing the data as bits and hashes
247    fn traverse_and_build(&mut self, height: u32, pos: u32, txids: &[Txid], matches: &[bool]) {
248        // Determine whether this node is the parent of at least one matched txid
249        let mut parent_of_match = false;
250        let mut p = pos << height;
251        while p < (pos + 1) << height && p < self.num_transactions {
252            parent_of_match |= matches[p as usize];
253            p += 1;
254        }
255        // Store as flag bit
256        self.bits.push(parent_of_match);
257
258        if height == 0 || !parent_of_match {
259            // If at height 0, or nothing interesting below, store hash and stop
260            let hash = self.calc_hash(height, pos, txids);
261            self.hashes.push(hash);
262        } else {
263            // Otherwise, don't store any hash, but descend into the subtrees
264            self.traverse_and_build(height - 1, pos * 2, txids, matches);
265            if pos * 2 + 1 < self.calc_tree_width(height - 1) {
266                self.traverse_and_build(height - 1, pos * 2 + 1, txids, matches);
267            }
268        }
269    }
270
271    /// Recursive function that traverses tree nodes, consuming the bits and hashes produced by
272    /// TraverseAndBuild. It returns the hash of the respective node and its respective index.
273    fn traverse_and_extract(
274        &self,
275        height: u32,
276        pos: u32,
277        bits_used: &mut u32,
278        hash_used: &mut u32,
279        matches: &mut Vec<Txid>,
280        indexes: &mut Vec<u32>,
281    ) -> Result<TxMerkleNode, MerkleBlockError> {
282        if *bits_used as usize >= self.bits.len() {
283            return Err(BadFormat("Overflowed the bits array".to_owned()));
284        }
285        let parent_of_match = self.bits[*bits_used as usize];
286        *bits_used += 1;
287        if height == 0 || !parent_of_match {
288            // If at height 0, or nothing interesting below, use stored hash and do not descend
289            if *hash_used as usize >= self.hashes.len() {
290                return Err(BadFormat("Overflowed the hash array".to_owned()));
291            }
292            let hash = self.hashes[*hash_used as usize];
293            *hash_used += 1;
294            if height == 0 && parent_of_match {
295                // in case of height 0, we have a matched txid
296                matches.push(Txid::from_inner(hash.into_inner()));
297                indexes.push(pos);
298            }
299            Ok(hash)
300        } else {
301            // otherwise, descend into the subtrees to extract matched txids and hashes
302            let left = self.traverse_and_extract(
303                height - 1,
304                pos * 2,
305                bits_used,
306                hash_used,
307                matches,
308                indexes,
309            )?;
310            let right;
311            if pos * 2 + 1 < self.calc_tree_width(height - 1) {
312                right = self.traverse_and_extract(
313                    height - 1,
314                    pos * 2 + 1,
315                    bits_used,
316                    hash_used,
317                    matches,
318                    indexes,
319                )?;
320                if right == left {
321                    // The left and right branches should never be identical, as the transaction
322                    // hashes covered by them must each be unique.
323                    return Err(BadFormat("Found identical transaction hashes".to_owned()));
324                }
325            } else {
326                right = left;
327            }
328            // and combine them before returning
329            Ok(PartialMerkleTree::parent_hash(left, right))
330        }
331    }
332
333    /// Helper method to produce SHA256D(left + right)
334    fn parent_hash(left: TxMerkleNode, right: TxMerkleNode) -> TxMerkleNode {
335        let mut encoder = TxMerkleNode::engine();
336        left.consensus_encode(&mut encoder).expect("engines don't error");
337        right.consensus_encode(&mut encoder).expect("engines don't error");
338        TxMerkleNode::from_engine(encoder)
339    }
340}
341
342impl Encodable for PartialMerkleTree {
343    fn consensus_encode<S: io::Write>(&self, mut s: S) -> Result<usize, io::Error> {
344        let ret = self.num_transactions.consensus_encode(&mut s)?
345            + self.hashes.consensus_encode(&mut s)?;
346        let mut bytes: Vec<u8> = vec![0; (self.bits.len() + 7) / 8];
347        for p in 0..self.bits.len() {
348            bytes[p / 8] |= (self.bits[p] as u8) << (p % 8) as u8;
349        }
350        Ok(ret + bytes.consensus_encode(s)?)
351    }
352}
353
354impl Decodable for PartialMerkleTree {
355    fn consensus_decode<D: io::Read>(mut d: D) -> Result<Self, encode::Error> {
356        let num_transactions: u32 = Decodable::consensus_decode(&mut d)?;
357        let hashes: Vec<TxMerkleNode> = Decodable::consensus_decode(&mut d)?;
358
359        let bytes: Vec<u8> = Decodable::consensus_decode(d)?;
360        let mut bits: Vec<bool> = vec![false; bytes.len() * 8];
361
362        for (p, bit) in bits.iter_mut().enumerate() {
363            *bit = (bytes[p / 8] & (1 << (p % 8) as u8)) != 0;
364        }
365        Ok(PartialMerkleTree {
366            num_transactions,
367            hashes,
368            bits,
369        })
370    }
371}
372
373/// Data structure that represents a block header paired to a partial merkle tree.
374///
375/// NOTE: This assumes that the given Block has *at least* 1 transaction. If the Block has 0 txs,
376/// it will hit an assertion.
377#[derive(PartialEq, Eq, Clone, Debug)]
378pub struct MerkleBlock {
379    /// The block header
380    pub header: BlockHeader,
381    /// Transactions making up a partial merkle tree
382    pub txn: PartialMerkleTree,
383}
384
385impl MerkleBlock {
386    /// Create a MerkleBlock from a block, that contains proofs for specific txids.
387    ///
388    /// The `block` is a full block containing the header and transactions and `match_txids` is a
389    /// function that returns true for the ids that should be included in the partial merkle tree.
390    ///
391    /// # Examples
392    ///
393    /// ```rust
394    /// use bitcoin::hash_types::Txid;
395    /// use bitcoin::hashes::hex::FromHex;
396    /// use bitcoin::{Block, MerkleBlock};
397    ///
398    /// // Block 80000
399    /// let block_bytes = Vec::from_hex("01000000ba8b9cda965dd8e536670f9ddec10e53aab14b20bacad2\
400    ///     7b9137190000000000190760b278fe7b8565fda3b968b918d5fd997f993b23674c0af3b6fde300b38f33\
401    ///     a5914ce6ed5b1b01e32f5702010000000100000000000000000000000000000000000000000000000000\
402    ///     00000000000000ffffffff0704e6ed5b1b014effffffff0100f2052a01000000434104b68a50eaa0287e\
403    ///     ff855189f949c1c6e5f58b37c88231373d8a59809cbae83059cc6469d65c665ccfd1cfeb75c6e8e19413\
404    ///     bba7fbff9bc762419a76d87b16086eac000000000100000001a6b97044d03da79c005b20ea9c0e1a6d9d\
405    ///     c12d9f7b91a5911c9030a439eed8f5000000004948304502206e21798a42fae0e854281abd38bacd1aee\
406    ///     d3ee3738d9e1446618c4571d1090db022100e2ac980643b0b82c0e88ffdfec6b64e3e6ba35e7ba5fdd7d\
407    ///     5d6cc8d25c6b241501ffffffff0100f2052a010000001976a914404371705fa9bd789a2fcd52d2c580b6\
408    ///     5d35549d88ac00000000").unwrap();
409    /// let block: Block = bitcoin::consensus::deserialize(&block_bytes).unwrap();
410    ///
411    /// // Create a merkle block containing a single transaction
412    /// let txid = Txid::from_hex(
413    ///     "5a4ebf66822b0b2d56bd9dc64ece0bc38ee7844a23ff1d7320a88c5fdb2ad3e2").unwrap();
414    /// let match_txids: Vec<Txid> = vec![txid].into_iter().collect();
415    /// let mb = MerkleBlock::from_block_with_predicate(&block, |t| match_txids.contains(t));
416    ///
417    /// // Authenticate and extract matched transaction ids
418    /// let mut matches: Vec<Txid> = vec![];
419    /// let mut index: Vec<u32> = vec![];
420    /// assert!(mb.extract_matches(&mut matches, &mut index).is_ok());
421    /// assert_eq!(txid, matches[0]);
422    /// ```
423    pub fn from_block_with_predicate<F>(block: &Block, match_txids: F) -> Self
424    where
425        F: Fn(&Txid) -> bool
426    {
427        let block_txids: Vec<_> = block.txdata.iter().map(Transaction::txid).collect();
428        Self::from_header_txids_with_predicate(&block.header, &block_txids, match_txids)
429    }
430
431    /// Create a MerkleBlock from a block, that contains proofs for specific txids.
432    #[cfg(feature = "std")]
433    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
434    #[deprecated(since = "0.26.2", note = "use from_block_with_predicate")]
435    pub fn from_block(block: &Block, match_txids: &::std::collections::HashSet<Txid>) -> Self {
436        Self::from_block_with_predicate(block, |t| match_txids.contains(t))
437    }
438
439    /// Create a MerkleBlock from the block's header and txids, that contain proofs for specific txids.
440    ///
441    /// The `header` is the block header, `block_txids` is the full list of txids included in the block and
442    /// `match_txids` is a function that returns true for the ids that should be included in the partial merkle tree.
443    pub fn from_header_txids_with_predicate<F>(
444        header: &BlockHeader,
445        block_txids: &[Txid],
446        match_txids: F,
447    ) -> Self
448    where
449        F: Fn(&Txid) -> bool
450    {
451        let matches: Vec<bool> = block_txids
452            .iter()
453            .map(match_txids)
454            .collect();
455
456        let pmt = PartialMerkleTree::from_txids(block_txids, &matches);
457        MerkleBlock {
458            header: *header,
459            txn: pmt,
460        }
461    }
462
463    /// Create a MerkleBlock from the block's header and txids, that should contain proofs for match_txids.
464    #[cfg(feature = "std")]
465    #[cfg_attr(docsrs, doc(cfg(feature = "std")))]
466    #[deprecated(since = "0.26.2", note = "use from_header_txids_with_predicate")]
467    pub fn from_header_txids(
468        header: &BlockHeader,
469        block_txids: &[Txid],
470        match_txids: &::std::collections::HashSet<Txid>,
471    ) -> Self {
472        Self::from_header_txids_with_predicate(header, block_txids, |t| match_txids.contains(t))
473    }
474
475    /// Extract the matching txid's represented by this partial merkle tree
476    /// and their respective indices within the partial tree.
477    /// returns Ok(()) on success, or error in case of failure
478    pub fn extract_matches(
479        &self,
480        matches: &mut Vec<Txid>,
481        indexes: &mut Vec<u32>,
482    ) -> Result<(), MerkleBlockError> {
483        let merkle_root = self.txn.extract_matches(matches, indexes)?;
484
485        if merkle_root.eq(&self.header.merkle_root) {
486            Ok(())
487        } else {
488            Err(MerkleRootMismatch)
489        }
490    }
491}
492
493impl Encodable for MerkleBlock {
494    fn consensus_encode<S: io::Write>(&self, mut s: S) -> Result<usize, io::Error> {
495        let len = self.header.consensus_encode(&mut s)?
496            + self.txn.consensus_encode(s)?;
497        Ok(len)
498    }
499}
500
501impl Decodable for MerkleBlock {
502    fn consensus_decode<D: io::Read>(mut d: D) -> Result<Self, encode::Error> {
503        Ok(MerkleBlock {
504            header: Decodable::consensus_decode(&mut d)?,
505            txn: Decodable::consensus_decode(d)?,
506        })
507    }
508}
509
510#[cfg(test)]
511mod tests {
512    use core::cmp::min;
513
514    use hashes::Hash;
515    use hashes::hex::{FromHex, ToHex};
516    use hash_types::{Txid, TxMerkleNode};
517    use secp256k1::rand::prelude::*;
518
519    use consensus::encode::{deserialize, serialize};
520    use util::hash::bitcoin_merkle_root;
521    use util::merkleblock::{MerkleBlock, PartialMerkleTree};
522    use Block;
523
524    #[test]
525    fn pmt_tests() {
526        let mut rng = thread_rng();
527        let tx_counts = vec![1, 4, 7, 17, 56, 100, 127, 256, 312, 513, 1000, 4095];
528
529        for num_tx in tx_counts {
530            // Create some fake tx ids
531            let txids = (1..num_tx + 1) // change to `1..=num_tx` when min Rust >= 1.26.0
532                .map(|i| Txid::from_hex(&format!("{:064x}", i)).unwrap())
533                .collect::<Vec<_>>();
534
535            // Calculate the merkle root and height
536            let hashes = txids.iter().map(|t| t.as_hash());
537            let merkle_root_1: TxMerkleNode = bitcoin_merkle_root(hashes).expect("hashes is not empty").into();
538            let mut height = 1;
539            let mut ntx = num_tx;
540            while ntx > 1 {
541                ntx = (ntx + 1) / 2;
542                height += 1;
543            }
544
545            // Check with random subsets with inclusion chances 1, 1/2, 1/4, ..., 1/128
546            for att in 1..15 {
547                let mut matches = vec![false; num_tx];
548                let mut match_txid1 = vec![];
549                for j in 0..num_tx {
550                    // Generate `att / 2` random bits
551                    let rand_bits = match att / 2 {
552                        0 => 0,
553                        bits => rng.gen::<u64>() >> (64 - bits),
554                    };
555                    let include = rand_bits == 0;
556                    matches[j] = include;
557
558                    if include {
559                        match_txid1.push(txids[j]);
560                    };
561                }
562
563                // Build the partial merkle tree
564                let pmt1 = PartialMerkleTree::from_txids(&txids, &matches);
565                let serialized = serialize(&pmt1);
566
567                // Verify PartialMerkleTree's size guarantees
568                let n = min(num_tx, 1 + match_txid1.len() * height);
569                assert!(serialized.len() <= 10 + (258 * n + 7) / 8);
570
571                // Deserialize into a tester copy
572                let pmt2: PartialMerkleTree =
573                    deserialize(&serialized).expect("Could not deserialize own data");
574
575                // Extract merkle root and matched txids from copy
576                let mut match_txid2: Vec<Txid> = vec![];
577                let mut indexes = vec![];
578                let merkle_root_2 = pmt2
579                    .extract_matches(&mut match_txid2, &mut indexes)
580                    .expect("Could not extract matches");
581
582                // Check that it has the same merkle root as the original, and a valid one
583                assert_eq!(merkle_root_1, merkle_root_2);
584                assert_ne!(merkle_root_2, TxMerkleNode::default());
585
586                // check that it contains the matched transactions (in the same order!)
587                assert_eq!(match_txid1, match_txid2);
588
589                // check that random bit flips break the authentication
590                for _ in 0..4 {
591                    let mut pmt3: PartialMerkleTree = deserialize(&serialized).unwrap();
592                    pmt3.damage(&mut rng);
593                    let mut match_txid3 = vec![];
594                    let merkle_root_3 = pmt3
595                        .extract_matches(&mut match_txid3, &mut indexes)
596                        .unwrap();
597                    assert_ne!(merkle_root_3, merkle_root_1);
598                }
599            }
600        }
601    }
602
603    #[test]
604    fn pmt_malleability() {
605        // Create some fake tx ids with the last 2 hashes repeating
606        let txids: Vec<Txid> = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 10]
607            .iter()
608            .map(|i| Txid::from_hex(&format!("{:064x}", i)).unwrap())
609            .collect();
610
611        let matches = vec![
612            false, false, false, false, false, false, false, false, false, true, true, false,
613        ];
614
615        let tree = PartialMerkleTree::from_txids(&txids, &matches);
616        // Should fail due to duplicate txs found
617        let result = tree.extract_matches(&mut vec![], &mut vec![]);
618        assert!(result.is_err());
619    }
620
621    #[test]
622    fn merkleblock_serialization() {
623        // Got it by running the rpc call
624        // `gettxoutproof '["220ebc64e21abece964927322cba69180ed853bb187fbc6923bac7d010b9d87a"]'`
625        let mb_hex =
626            "0100000090f0a9f110702f808219ebea1173056042a714bad51b916cb6800000000000005275289558f51c\
627            9966699404ae2294730c3c9f9bda53523ce50e9b95e558da2fdb261b4d4c86041b1ab1bf930900000005fac\
628            7708a6e81b2a986dea60db2663840ed141130848162eb1bd1dee54f309a1b2ee1e12587e497ada70d9bd10d\
629            31e83f0a924825b96cb8d04e8936d793fb60db7ad8b910d0c7ba2369bc7f18bb53d80e1869ba2c32274996c\
630            ebe1ae264bc0e2289189ff0316cdc10511da71da757e553cada9f3b5b1434f3923673adb57d83caac392c38\
631            af156d6fc30b55fad4112df2b95531e68114e9ad10011e72f7b7cfdb025700";
632
633        let mb: MerkleBlock = deserialize(&Vec::from_hex(mb_hex).unwrap()).unwrap();
634        assert_eq!(get_block_13b8a().block_hash(), mb.header.block_hash());
635        assert_eq!(
636            mb.header.merkle_root,
637            mb.txn.extract_matches(&mut vec![], &mut vec![]).unwrap()
638        );
639        // Serialize again and check that it matches the original bytes
640        assert_eq!(mb_hex, serialize(&mb).to_hex().as_str());
641    }
642
643    /// Create a CMerkleBlock using a list of txids which will be found in the
644    /// given block.
645    #[test]
646    fn merkleblock_construct_from_txids_found() {
647        let block = get_block_13b8a();
648
649        let txids: Vec<Txid> = [
650            "74d681e0e03bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20",
651            "f9fc751cb7dc372406a9f8d738d5e6f8f63bab71986a39cf36ee70ee17036d07",
652        ]
653        .iter()
654        .map(|hex| Txid::from_hex(hex).unwrap())
655        .collect();
656
657        let txid1 = txids[0];
658        let txid2 = txids[1];
659        let txids = vec![txid1, txid2];
660
661        let merkle_block = MerkleBlock::from_block_with_predicate(&block, |t| txids.contains(t));
662
663        assert_eq!(merkle_block.header.block_hash(), block.block_hash());
664
665        let mut matches: Vec<Txid> = vec![];
666        let mut index: Vec<u32> = vec![];
667
668        assert_eq!(
669            merkle_block
670                .txn
671                .extract_matches(&mut matches, &mut index)
672                .unwrap(),
673            block.header.merkle_root
674        );
675        assert_eq!(matches.len(), 2);
676
677        // Ordered by occurrence in depth-first tree traversal.
678        assert_eq!(matches[0], txid2);
679        assert_eq!(index[0], 1);
680
681        assert_eq!(matches[1], txid1);
682        assert_eq!(index[1], 8);
683    }
684
685    /// Create a CMerkleBlock using a list of txids which will not be found in the given block
686    #[test]
687    fn merkleblock_construct_from_txids_not_found() {
688        let block = get_block_13b8a();
689        let txids: Vec<Txid> = ["c0ffee00003bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20"]
690            .iter()
691            .map(|hex| Txid::from_hex(hex).unwrap())
692            .collect();
693
694        let merkle_block = MerkleBlock::from_block_with_predicate(&block, |t| txids.contains(t));
695
696        assert_eq!(merkle_block.header.block_hash(), block.block_hash());
697
698        let mut matches: Vec<Txid> = vec![];
699        let mut index: Vec<u32> = vec![];
700
701        assert_eq!(
702            merkle_block
703                .txn
704                .extract_matches(&mut matches, &mut index)
705                .unwrap(),
706            block.header.merkle_root
707        );
708        assert_eq!(matches.len(), 0);
709        assert_eq!(index.len(), 0);
710    }
711
712    impl PartialMerkleTree {
713        /// Flip one bit in one of the hashes - this should break the authentication
714        fn damage(&mut self, rng: &mut ThreadRng) {
715            let n = rng.gen_range(0.. self.hashes.len());
716            let bit = rng.gen::<u8>();
717            let hashes = &mut self.hashes;
718            let mut hash = hashes[n].into_inner();
719            hash[(bit >> 3) as usize] ^= 1 << (bit & 7);
720            hashes[n] = TxMerkleNode::from_slice(&hash).unwrap();
721        }
722    }
723
724    /// Returns a real block (0000000000013b8ab2cd513b0261a14096412195a72a0c4827d229dcc7e0f7af)
725    /// with 9 txs.
726    fn get_block_13b8a() -> Block {
727        let block_hex =
728            "0100000090f0a9f110702f808219ebea1173056042a714bad51b916cb6800000000000005275289558f51c\
729            9966699404ae2294730c3c9f9bda53523ce50e9b95e558da2fdb261b4d4c86041b1ab1bf930901000000010\
730            000000000000000000000000000000000000000000000000000000000000000ffffffff07044c86041b0146\
731            ffffffff0100f2052a01000000434104e18f7afbe4721580e81e8414fc8c24d7cfacf254bb5c7b949450c3e\
732            997c2dc1242487a8169507b631eb3771f2b425483fb13102c4eb5d858eef260fe70fbfae0ac000000000100\
733            00000196608ccbafa16abada902780da4dc35dafd7af05fa0da08cf833575f8cf9e836000000004a4930460\
734            22100dab24889213caf43ae6adc41cf1c9396c08240c199f5225acf45416330fd7dbd022100fe37900e0644\
735            bf574493a07fc5edba06dbc07c311b947520c2d514bc5725dcb401ffffffff0100f2052a010000001976a91\
736            4f15d1921f52e4007b146dfa60f369ed2fc393ce288ac000000000100000001fb766c1288458c2bafcfec81\
737            e48b24d98ec706de6b8af7c4e3c29419bfacb56d000000008c493046022100f268ba165ce0ad2e6d93f089c\
738            fcd3785de5c963bb5ea6b8c1b23f1ce3e517b9f022100da7c0f21adc6c401887f2bfd1922f11d76159cbc59\
739            7fbd756a23dcbb00f4d7290141042b4e8625a96127826915a5b109852636ad0da753c9e1d5606a50480cd0c\
740            40f1f8b8d898235e571fe9357d9ec842bc4bba1827daaf4de06d71844d0057707966affffffff0280969800\
741            000000001976a9146963907531db72d0ed1a0cfb471ccb63923446f388ac80d6e34c000000001976a914f06\
742            88ba1c0d1ce182c7af6741e02658c7d4dfcd388ac000000000100000002c40297f730dd7b5a99567eb8d27b\
743            78758f607507c52292d02d4031895b52f2ff010000008b483045022100f7edfd4b0aac404e5bab4fd3889e0\
744            c6c41aa8d0e6fa122316f68eddd0a65013902205b09cc8b2d56e1cd1f7f2fafd60a129ed94504c4ac7bdc67\
745            b56fe67512658b3e014104732012cb962afa90d31b25d8fb0e32c94e513ab7a17805c14ca4c3423e18b4fb5\
746            d0e676841733cb83abaf975845c9f6f2a8097b7d04f4908b18368d6fc2d68ecffffffffca5065ff9617cbcb\
747            a45eb23726df6498a9b9cafed4f54cbab9d227b0035ddefb000000008a473044022068010362a13c7f9919f\
748            a832b2dee4e788f61f6f5d344a7c2a0da6ae740605658022006d1af525b9a14a35c003b78b72bd59738cd67\
749            6f845d1ff3fc25049e01003614014104732012cb962afa90d31b25d8fb0e32c94e513ab7a17805c14ca4c34\
750            23e18b4fb5d0e676841733cb83abaf975845c9f6f2a8097b7d04f4908b18368d6fc2d68ecffffffff01001e\
751            c4110200000043410469ab4181eceb28985b9b4e895c13fa5e68d85761b7eee311db5addef76fa862186513\
752            4a221bd01f28ec9999ee3e021e60766e9d1f3458c115fb28650605f11c9ac000000000100000001cdaf2f75\
753            8e91c514655e2dc50633d1e4c84989f8aa90a0dbc883f0d23ed5c2fa010000008b48304502207ab51be6f12\
754            a1962ba0aaaf24a20e0b69b27a94fac5adf45aa7d2d18ffd9236102210086ae728b370e5329eead9accd880\
755            d0cb070aea0c96255fae6c4f1ddcce1fd56e014104462e76fd4067b3a0aa42070082dcb0bf2f388b6495cf3\
756            3d789904f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312ef1c0e8ebbb12dcd4ffff\
757            ffff02404b4c00000000001976a9142b6ba7c9d796b75eef7942fc9288edd37c32f5c388ac002d310100000\
758            0001976a9141befba0cdc1ad56529371864d9f6cb042faa06b588ac000000000100000001b4a47603e71b61\
759            bc3326efd90111bf02d2f549b067f4c4a8fa183b57a0f800cb010000008a4730440220177c37f9a505c3f1a\
760            1f0ce2da777c339bd8339ffa02c7cb41f0a5804f473c9230220585b25a2ee80eb59292e52b987dad92acb0c\
761            64eced92ed9ee105ad153cdb12d001410443bd44f683467e549dae7d20d1d79cbdb6df985c6e9c029c8d0c6\
762            cb46cc1a4d3cf7923c5021b27f7a0b562ada113bc85d5fda5a1b41e87fe6e8802817cf69996ffffffff0280\
763            651406000000001976a9145505614859643ab7b547cd7f1f5e7e2a12322d3788ac00aa0271000000001976a\
764            914ea4720a7a52fc166c55ff2298e07baf70ae67e1b88ac00000000010000000586c62cd602d219bb60edb1\
765            4a3e204de0705176f9022fe49a538054fb14abb49e010000008c493046022100f2bc2aba2534becbdf062eb\
766            993853a42bbbc282083d0daf9b4b585bd401aa8c9022100b1d7fd7ee0b95600db8535bbf331b19eed8d961f\
767            7a8e54159c53675d5f69df8c014104462e76fd4067b3a0aa42070082dcb0bf2f388b6495cf33d789904f07d\
768            0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312ef1c0e8ebbb12dcd4ffffffff03ad0e58\
769            ccdac3df9dc28a218bcf6f1997b0a93306faaa4b3a28ae83447b2179010000008b483045022100be12b2937\
770            179da88599e27bb31c3525097a07cdb52422d165b3ca2f2020ffcf702200971b51f853a53d644ebae9ec8f3\
771            512e442b1bcb6c315a5b491d119d10624c83014104462e76fd4067b3a0aa42070082dcb0bf2f388b6495cf3\
772            3d789904f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312ef1c0e8ebbb12dcd4ffff\
773            ffff2acfcab629bbc8685792603762c921580030ba144af553d271716a95089e107b010000008b483045022\
774            100fa579a840ac258871365dd48cd7552f96c8eea69bd00d84f05b283a0dab311e102207e3c0ee9234814cf\
775            bb1b659b83671618f45abc1326b9edcc77d552a4f2a805c0014104462e76fd4067b3a0aa42070082dcb0bf2\
776            f388b6495cf33d789904f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15312ef1c0e8eb\
777            bb12dcd4ffffffffdcdc6023bbc9944a658ddc588e61eacb737ddf0a3cd24f113b5a8634c517fcd20000000\
778            08b4830450221008d6df731df5d32267954bd7d2dda2302b74c6c2a6aa5c0ca64ecbabc1af03c75022010e5\
779            5c571d65da7701ae2da1956c442df81bbf076cdbac25133f99d98a9ed34c014104462e76fd4067b3a0aa420\
780            70082dcb0bf2f388b6495cf33d789904f07d0f55c40fbd4b82963c69b3dc31895d0c772c812b1d5fbcade15\
781            312ef1c0e8ebbb12dcd4ffffffffe15557cd5ce258f479dfd6dc6514edf6d7ed5b21fcfa4a038fd69f06b83\
782            ac76e010000008b483045022023b3e0ab071eb11de2eb1cc3a67261b866f86bf6867d4558165f7c8c8aca2d\
783            86022100dc6e1f53a91de3efe8f63512850811f26284b62f850c70ca73ed5de8771fb451014104462e76fd4\
784            067b3a0aa42070082dcb0bf2f388b6495cf33d789904f07d0f55c40fbd4b82963c69b3dc31895d0c772c812\
785            b1d5fbcade15312ef1c0e8ebbb12dcd4ffffffff01404b4c00000000001976a9142b6ba7c9d796b75eef794\
786            2fc9288edd37c32f5c388ac00000000010000000166d7577163c932b4f9690ca6a80b6e4eb001f0a2fa9023\
787            df5595602aae96ed8d000000008a4730440220262b42546302dfb654a229cefc86432b89628ff259dc87edd\
788            1154535b16a67e102207b4634c020a97c3e7bbd0d4d19da6aa2269ad9dded4026e896b213d73ca4b63f0141\
789            04979b82d02226b3a4597523845754d44f13639e3bf2df5e82c6aab2bdc79687368b01b1ab8b19875ae3c90\
790            d661a3d0a33161dab29934edeb36aa01976be3baf8affffffff02404b4c00000000001976a9144854e695a0\
791            2af0aeacb823ccbc272134561e0a1688ac40420f00000000001976a914abee93376d6b37b5c2940655a6fca\
792            f1c8e74237988ac0000000001000000014e3f8ef2e91349a9059cb4f01e54ab2597c1387161d3da89919f7e\
793            a6acdbb371010000008c49304602210081f3183471a5ca22307c0800226f3ef9c353069e0773ac76bb58065\
794            4d56aa523022100d4c56465bdc069060846f4fbf2f6b20520b2a80b08b168b31e66ddb9c694e24001410497\
795            6c79848e18251612f8940875b2b08d06e6dc73b9840e8860c066b7e87432c477e9a59a453e71e6d76d5fe34\
796            058b800a098fc1740ce3012e8fc8a00c96af966ffffffff02c0e1e400000000001976a9144134e75a6fcb60\
797            42034aab5e18570cf1f844f54788ac404b4c00000000001976a9142b6ba7c9d796b75eef7942fc9288edd37\
798            c32f5c388ac00000000";
799        deserialize(&Vec::from_hex(block_hex).unwrap()).unwrap()
800    }
801}
sapio_bitcoin/util/merkleblock.rs

sapio_bitcoin/util/
merkleblock.rs
