//! Tagged hashes for use in signature calculation and verification.
use bitcoin::hashes::{Hash, HashEngine, sha256};
+use bitcoin::secp256k1::{Message, PublicKey, Secp256k1, self};
+use bitcoin::secp256k1::schnorr::Signature;
use crate::io;
-use crate::util::ser::{BigSize, Readable};
+use crate::util::ser::{BigSize, Readable, Writeable, Writer};
use crate::prelude::*;
/// Valid type range for signature TLV records.
const SIGNATURE_TYPES: core::ops::RangeInclusive<u64> = 240..=1000;
+tlv_stream!(SignatureTlvStream, SignatureTlvStreamRef, SIGNATURE_TYPES, {
+ (240, signature: Signature),
+});
+
+/// Error when signing messages.
+#[derive(Debug, PartialEq)]
+pub enum SignError<E> {
+ /// User-defined error when signing the message.
+ Signing(E),
+ /// Error when verifying the produced signature using the given pubkey.
+ Verification(secp256k1::Error),
+}
+
+/// Signs a message digest consisting of a tagged hash of the given bytes, checking if it can be
+/// verified with the supplied pubkey.
+///
+/// Panics if `bytes` is not a well-formed TLV stream containing at least one TLV record.
+pub(super) fn sign_message<F, E>(
+ sign: F, tag: &str, bytes: &[u8], pubkey: PublicKey,
+) -> Result<Signature, SignError<E>>
+where
+ F: FnOnce(&Message) -> Result<Signature, E>
+{
+ let digest = message_digest(tag, bytes);
+ let signature = sign(&digest).map_err(|e| SignError::Signing(e))?;
+
+ let pubkey = pubkey.into();
+ let secp_ctx = Secp256k1::verification_only();
+ secp_ctx.verify_schnorr(&signature, &digest, &pubkey).map_err(|e| SignError::Verification(e))?;
+
+ Ok(signature)
+}
+
+/// Verifies the signature with a pubkey over the given bytes using a tagged hash as the message
+/// digest.
+///
+/// Panics if `bytes` is not a well-formed TLV stream containing at least one TLV record.
+pub(super) fn verify_signature(
+ signature: &Signature, tag: &str, bytes: &[u8], pubkey: PublicKey,
+) -> Result<(), secp256k1::Error> {
+ let digest = message_digest(tag, bytes);
+ let pubkey = pubkey.into();
+ let secp_ctx = Secp256k1::verification_only();
+ secp_ctx.verify_schnorr(signature, &digest, &pubkey)
+}
+
+pub(super) fn message_digest(tag: &str, bytes: &[u8]) -> Message {
+ let tag = sha256::Hash::hash(tag.as_bytes());
+ let merkle_root = root_hash(bytes);
+ Message::from_slice(&tagged_hash(tag, merkle_root)).unwrap()
+}
+
/// Computes a merkle root hash for the given data, which must be a well-formed TLV stream
/// containing at least one TLV record.
fn root_hash(data: &[u8]) -> sha256::Hash {
- let mut tlv_stream = TlvStream::new(&data[..]).peekable();
let nonce_tag = tagged_hash_engine(sha256::Hash::from_engine({
+ let first_tlv_record = TlvStream::new(&data[..]).next().unwrap();
let mut engine = sha256::Hash::engine();
engine.input("LnNonce".as_bytes());
- engine.input(tlv_stream.peek().unwrap().record_bytes);
+ engine.input(first_tlv_record.record_bytes);
engine
}));
let leaf_tag = tagged_hash_engine(sha256::Hash::hash("LnLeaf".as_bytes()));
let branch_tag = tagged_hash_engine(sha256::Hash::hash("LnBranch".as_bytes()));
let mut leaves = Vec::new();
- for record in tlv_stream {
- if !SIGNATURE_TYPES.contains(&record.r#type) {
- leaves.push(tagged_hash_from_engine(leaf_tag.clone(), &record));
- leaves.push(tagged_hash_from_engine(nonce_tag.clone(), &record.type_bytes));
- }
+ let tlv_stream = TlvStream::new(&data[..]);
+ for record in tlv_stream.skip_signatures() {
+ leaves.push(tagged_hash_from_engine(leaf_tag.clone(), &record.record_bytes));
+ leaves.push(tagged_hash_from_engine(nonce_tag.clone(), &record.type_bytes));
}
// Calculate the merkle root hash in place.
data: io::Cursor::new(data),
}
}
+
+ fn skip_signatures(self) -> core::iter::Filter<TlvStream<'a>, fn(&TlvRecord) -> bool> {
+ self.filter(|record| !SIGNATURE_TYPES.contains(&record.r#type))
+ }
}
/// A slice into a [`TlvStream`] for a record.
record_bytes: &'a [u8],
}
-impl AsRef<[u8]> for TlvRecord<'_> {
- fn as_ref(&self) -> &[u8] { &self.record_bytes }
-}
-
impl<'a> Iterator for TlvStream<'a> {
type Item = TlvRecord<'a>;
}
}
+/// Encoding for a pre-serialized TLV stream that excludes any signature TLV records.
+///
+/// Panics if the wrapped bytes are not a well-formed TLV stream.
+pub(super) struct WithoutSignatures<'a>(pub &'a Vec<u8>);
+
+impl<'a> Writeable for WithoutSignatures<'a> {
+ #[inline]
+ fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+ let tlv_stream = TlvStream::new(&self.0[..]);
+ for record in tlv_stream.skip_signatures() {
+ writer.write_all(record.record_bytes)?;
+ }
+ Ok(())
+ }
+}
+
#[cfg(test)]
mod tests {
+ use super::{TlvStream, WithoutSignatures};
+
use bitcoin::hashes::{Hash, sha256};
+ use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey};
+ use core::convert::Infallible;
+ use crate::offers::offer::{Amount, OfferBuilder};
+ use crate::offers::invoice_request::InvoiceRequest;
+ use crate::offers::parse::Bech32Encode;
+ use crate::util::ser::Writeable;
#[test]
fn calculates_merkle_root_hash() {
sha256::Hash::from_slice(&hex::decode("ab2e79b1283b0b31e0b035258de23782df6b89a38cfa7237bde69aed1a658c5d").unwrap()).unwrap(),
);
}
+
+ #[test]
+ fn calculates_merkle_root_hash_from_invoice_request() {
+ let secp_ctx = Secp256k1::new();
+ let recipient_pubkey = {
+ let secret_key = SecretKey::from_slice(&hex::decode("4141414141414141414141414141414141414141414141414141414141414141").unwrap()).unwrap();
+ KeyPair::from_secret_key(&secp_ctx, &secret_key).public_key()
+ };
+ let payer_keys = {
+ let secret_key = SecretKey::from_slice(&hex::decode("4242424242424242424242424242424242424242424242424242424242424242").unwrap()).unwrap();
+ KeyPair::from_secret_key(&secp_ctx, &secret_key)
+ };
+
+ // BOLT 12 test vectors
+ let invoice_request = OfferBuilder::new("A Mathematical Treatise".into(), recipient_pubkey)
+ .amount(Amount::Currency { iso4217_code: *b"USD", amount: 100 })
+ .build_unchecked()
+ .request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
+ .build_unchecked()
+ .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &payer_keys)))
+ .unwrap();
+ assert_eq!(
+ invoice_request.to_string(),
+ "lnr1qqyqqqqqqqqqqqqqqcp4256ypqqkgzshgysy6ct5dpjk6ct5d93kzmpq23ex2ct5d9ek293pqthvwfzadd7jejes8q9lhc4rvjxd022zv5l44g6qah82ru5rdpnpjkppqvjx204vgdzgsqpvcp4mldl3plscny0rt707gvpdh6ndydfacz43euzqhrurageg3n7kafgsek6gz3e9w52parv8gs2hlxzk95tzeswywffxlkeyhml0hh46kndmwf4m6xma3tkq2lu04qz3slje2rfthc89vss",
+ );
+ assert_eq!(
+ super::root_hash(&invoice_request.bytes[..]),
+ sha256::Hash::from_slice(&hex::decode("608407c18ad9a94d9ea2bcdbe170b6c20c462a7833a197621c916f78cf18e624").unwrap()).unwrap(),
+ );
+ }
+
+ #[test]
+ fn skips_encoding_signature_tlv_records() {
+ let secp_ctx = Secp256k1::new();
+ let recipient_pubkey = {
+ let secret_key = SecretKey::from_slice(&[41; 32]).unwrap();
+ KeyPair::from_secret_key(&secp_ctx, &secret_key).public_key()
+ };
+ let payer_keys = {
+ let secret_key = SecretKey::from_slice(&[42; 32]).unwrap();
+ KeyPair::from_secret_key(&secp_ctx, &secret_key)
+ };
+
+ let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey)
+ .amount_msats(100)
+ .build_unchecked()
+ .request_invoice(vec![0; 8], payer_keys.public_key()).unwrap()
+ .build_unchecked()
+ .sign::<_, Infallible>(|digest| Ok(secp_ctx.sign_schnorr_no_aux_rand(digest, &payer_keys)))
+ .unwrap();
+
+ let mut bytes_without_signature = Vec::new();
+ WithoutSignatures(&invoice_request.bytes).write(&mut bytes_without_signature).unwrap();
+
+ assert_ne!(bytes_without_signature, invoice_request.bytes);
+ assert_eq!(
+ TlvStream::new(&bytes_without_signature).count(),
+ TlvStream::new(&invoice_request.bytes).count() - 1,
+ );
+ }
+
+ impl AsRef<[u8]> for InvoiceRequest {
+ fn as_ref(&self) -> &[u8] {
+ &self.bytes
+ }
+ }
+
+ impl Bech32Encode for InvoiceRequest {
+ const BECH32_HRP: &'static str = "lnr";
+ }
+
+ impl core::fmt::Display for InvoiceRequest {
+ fn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {
+ self.fmt_bech32_str(f)
+ }
+ }
}
projects / rust-lightning / blobdiff