1 // This file is Copyright its original authors, visible in version control
4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
7 // You may not use this file except in accordance with one or both of these
10 //! Tagged hashes for use in signature calculation and verification.
12 use bitcoin::hashes::{Hash, HashEngine, sha256};
13 use bitcoin::secp256k1::{Message, PublicKey, Secp256k1, self};
14 use bitcoin::secp256k1::schnorr::Signature;
16 use crate::util::ser::{BigSize, Readable};
18 use crate::prelude::*;
20 /// Valid type range for signature TLV records.
21 const SIGNATURE_TYPES: core::ops::RangeInclusive<u64> = 240..=1000;
23 tlv_stream!(SignatureTlvStream, SignatureTlvStreamRef, SIGNATURE_TYPES, {
24 (240, signature: Signature),
27 /// Error when signing messages.
28 #[derive(Debug, PartialEq)]
29 pub enum SignError<E> {
30 /// User-defined error when signing the message.
32 /// Error when verifying the produced signature using the given pubkey.
33 Verification(secp256k1::Error),
36 /// Signs a message digest consisting of a tagged hash of the given bytes, checking if it can be
37 /// verified with the supplied pubkey.
39 /// Panics if `bytes` is not a well-formed TLV stream containing at least one TLV record.
40 pub(super) fn sign_message<F, E>(
41 sign: F, tag: &str, bytes: &[u8], pubkey: PublicKey,
42 ) -> Result<Signature, SignError<E>>
44 F: FnOnce(&Message) -> Result<Signature, E>
46 let digest = message_digest(tag, bytes);
47 let signature = sign(&digest).map_err(|e| SignError::Signing(e))?;
49 let pubkey = pubkey.into();
50 let secp_ctx = Secp256k1::verification_only();
51 secp_ctx.verify_schnorr(&signature, &digest, &pubkey).map_err(|e| SignError::Verification(e))?;
56 /// Verifies the signature with a pubkey over the given bytes using a tagged hash as the message
59 /// Panics if `bytes` is not a well-formed TLV stream containing at least one TLV record.
60 pub(super) fn verify_signature(
61 signature: &Signature, tag: &str, bytes: &[u8], pubkey: PublicKey,
62 ) -> Result<(), secp256k1::Error> {
63 let digest = message_digest(tag, bytes);
64 let pubkey = pubkey.into();
65 let secp_ctx = Secp256k1::verification_only();
66 secp_ctx.verify_schnorr(signature, &digest, &pubkey)
69 fn message_digest(tag: &str, bytes: &[u8]) -> Message {
70 let tag = sha256::Hash::hash(tag.as_bytes());
71 let merkle_root = root_hash(bytes);
72 Message::from_slice(&tagged_hash(tag, merkle_root)).unwrap()
75 /// Computes a merkle root hash for the given data, which must be a well-formed TLV stream
76 /// containing at least one TLV record.
77 fn root_hash(data: &[u8]) -> sha256::Hash {
78 let nonce_tag = tagged_hash_engine(sha256::Hash::from_engine({
79 let first_tlv_record = TlvStream::new(&data[..]).next().unwrap();
80 let mut engine = sha256::Hash::engine();
81 engine.input("LnNonce".as_bytes());
82 engine.input(first_tlv_record.record_bytes);
85 let leaf_tag = tagged_hash_engine(sha256::Hash::hash("LnLeaf".as_bytes()));
86 let branch_tag = tagged_hash_engine(sha256::Hash::hash("LnBranch".as_bytes()));
88 let mut leaves = Vec::new();
89 let tlv_stream = TlvStream::new(&data[..]);
90 for record in tlv_stream.skip_signatures() {
91 leaves.push(tagged_hash_from_engine(leaf_tag.clone(), &record.record_bytes));
92 leaves.push(tagged_hash_from_engine(nonce_tag.clone(), &record.type_bytes));
95 // Calculate the merkle root hash in place.
96 let num_leaves = leaves.len();
98 let step = 2 << level;
99 let offset = step / 2;
100 if offset >= num_leaves {
104 let left_branches = (0..num_leaves).step_by(step);
105 let right_branches = (offset..num_leaves).step_by(step);
106 for (i, j) in left_branches.zip(right_branches) {
107 leaves[i] = tagged_branch_hash_from_engine(branch_tag.clone(), leaves[i], leaves[j]);
111 *leaves.first().unwrap()
114 fn tagged_hash<T: AsRef<[u8]>>(tag: sha256::Hash, msg: T) -> sha256::Hash {
115 let engine = tagged_hash_engine(tag);
116 tagged_hash_from_engine(engine, msg)
119 fn tagged_hash_engine(tag: sha256::Hash) -> sha256::HashEngine {
120 let mut engine = sha256::Hash::engine();
121 engine.input(tag.as_ref());
122 engine.input(tag.as_ref());
126 fn tagged_hash_from_engine<T: AsRef<[u8]>>(mut engine: sha256::HashEngine, msg: T) -> sha256::Hash {
127 engine.input(msg.as_ref());
128 sha256::Hash::from_engine(engine)
131 fn tagged_branch_hash_from_engine(
132 mut engine: sha256::HashEngine, leaf1: sha256::Hash, leaf2: sha256::Hash,
135 engine.input(leaf1.as_ref());
136 engine.input(leaf2.as_ref());
138 engine.input(leaf2.as_ref());
139 engine.input(leaf1.as_ref());
141 sha256::Hash::from_engine(engine)
144 /// [`Iterator`] over a sequence of bytes yielding [`TlvRecord`]s. The input is assumed to be a
145 /// well-formed TLV stream.
146 struct TlvStream<'a> {
147 data: io::Cursor<&'a [u8]>,
150 impl<'a> TlvStream<'a> {
151 fn new(data: &'a [u8]) -> Self {
153 data: io::Cursor::new(data),
157 fn skip_signatures(self) -> core::iter::Filter<TlvStream<'a>, fn(&TlvRecord) -> bool> {
158 self.filter(|record| !SIGNATURE_TYPES.contains(&record.r#type))
162 /// A slice into a [`TlvStream`] for a record.
163 struct TlvRecord<'a> {
165 type_bytes: &'a [u8],
166 // The entire TLV record.
167 record_bytes: &'a [u8],
170 impl<'a> Iterator for TlvStream<'a> {
171 type Item = TlvRecord<'a>;
173 fn next(&mut self) -> Option<Self::Item> {
174 if self.data.position() < self.data.get_ref().len() as u64 {
175 let start = self.data.position();
177 let r#type = <BigSize as Readable>::read(&mut self.data).unwrap().0;
178 let offset = self.data.position();
179 let type_bytes = &self.data.get_ref()[start as usize..offset as usize];
181 let length = <BigSize as Readable>::read(&mut self.data).unwrap().0;
182 let offset = self.data.position();
183 let end = offset + length;
185 let _value = &self.data.get_ref()[offset as usize..end as usize];
186 let record_bytes = &self.data.get_ref()[start as usize..end as usize];
188 self.data.set_position(end);
190 Some(TlvRecord { r#type, type_bytes, record_bytes })
199 use bitcoin::hashes::{Hash, sha256};
200 use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
201 use core::convert::Infallible;
202 use crate::offers::offer::{Amount, OfferBuilder};
203 use crate::offers::invoice_request::InvoiceRequest;
204 use crate::offers::parse::Bech32Encode;
207 fn calculates_merkle_root_hash() {
208 // BOLT 12 test vectors
209 macro_rules! tlv1 { () => { "010203e8" } }
210 macro_rules! tlv2 { () => { "02080000010000020003" } }
211 macro_rules! tlv3 { () => { "03310266e4598d1d3c415f572a8488830b60f7e744ed9235eb0b1ba93283b315c0351800000000000000010000000000000002" } }
213 super::root_hash(&hex::decode(tlv1!()).unwrap()),
214 sha256::Hash::from_slice(&hex::decode("b013756c8fee86503a0b4abdab4cddeb1af5d344ca6fc2fa8b6c08938caa6f93").unwrap()).unwrap(),
217 super::root_hash(&hex::decode(concat!(tlv1!(), tlv2!())).unwrap()),
218 sha256::Hash::from_slice(&hex::decode("c3774abbf4815aa54ccaa026bff6581f01f3be5fe814c620a252534f434bc0d1").unwrap()).unwrap(),
221 super::root_hash(&hex::decode(concat!(tlv1!(), tlv2!(), tlv3!())).unwrap()),
222 sha256::Hash::from_slice(&hex::decode("ab2e79b1283b0b31e0b035258de23782df6b89a38cfa7237bde69aed1a658c5d").unwrap()).unwrap(),
227 fn calculates_merkle_root_hash_from_invoice_request() {
228 let secp_ctx = Secp256k1::new();
229 let recipient_pubkey = {
230 let secret_key = SecretKey::from_slice(&hex::decode("4141414141414141414141414141414141414141414141414141414141414141").unwrap()).unwrap();
231 KeyPair::from_secret_key(&secp_ctx, &secret_key).public_key()
234 let secret_key = SecretKey::from_slice(&hex::decode("4242424242424242424242424242424242424242424242424242424242424242").unwrap()).unwrap();
235 KeyPair::from_secret_key(&secp_ctx, &secret_key)
238 // BOLT 12 test vectors
239 let invoice_request = OfferBuilder::new("A Mathematical Treatise".into(), recipient_pubkey)
240 .amount(Amount::Currency { iso4217_code: *b"USD", amount: 100 })
242 .request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
244 .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &payer_keys)))
247 invoice_request.to_string(),
248 "lnr1qqyqqqqqqqqqqqqqqcp4256ypqqkgzshgysy6ct5dpjk6ct5d93kzmpq23ex2ct5d9ek293pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpjkppqvjx204vgdzgsqpvcp4mldl3plscny0rt707gvpdh6ndydfacz43euzqhrurageg3n7kafgsek6gz3e9w52parv8gs2hlxzk95tzeswywffxlkeyhml0hh46kndmwf4m6xma3tkq2lu04qz3slje2rfthc89vss",
251 super::root_hash(&invoice_request.bytes[..]),
252 sha256::Hash::from_slice(&hex::decode("608407c18ad9a94d9ea2bcdbe170b6c20c462a7833a197621c916f78cf18e624").unwrap()).unwrap(),
256 impl AsRef<[u8]> for InvoiceRequest {
257 fn as_ref(&self) -> &[u8] {
262 impl Bech32Encode for InvoiceRequest {
263 const BECH32_HRP: &'static str = "lnr";
266 impl core::fmt::Display for InvoiceRequest {
267 fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
268 self.fmt_bech32_str(f)