use bitcoin::secp256k1::{SecretKey, PublicKey, Scalar};
use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Message};
-use bitcoin::secp256k1::Error as SecpError;
use bitcoin::{PackedLockTime, secp256k1, Sequence, Witness};
use bitcoin::PublicKey as BitcoinPublicKey;
/// Derives a per-commitment-transaction private key (eg an htlc key or delayed_payment key)
/// from the base secret and the per_commitment_point.
-///
-/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
-/// generated (ie our own).
-pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, SecpError> {
+pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> SecretKey {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
sha.input(&PublicKey::from_secret_key(&secp_ctx, &base_secret).serialize());
let res = Sha256::from_engine(sha).into_inner();
base_secret.clone().add_tweak(&Scalar::from_be_bytes(res).unwrap())
+ .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak contains the hash of the key.")
}
/// Derives a per-commitment-transaction public key (eg an htlc key or a delayed_payment key)
/// from the base point and the per_commitment_key. This is the public equivalent of
/// derive_private_key - using only public keys to derive a public key instead of private keys.
-///
-/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
-/// generated (ie our own).
-pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, SecpError> {
+pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> PublicKey {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
sha.input(&base_point.serialize());
let res = Sha256::from_engine(sha).into_inner();
- let hashkey = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&res)?);
+ let hashkey = PublicKey::from_secret_key(&secp_ctx,
+ &SecretKey::from_slice(&res).expect("Hashes should always be valid keys unless SHA-256 is broken"));
base_point.combine(&hashkey)
+ .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak contains the hash of the key.")
}
/// Derives a per-commitment-transaction revocation key from its constituent parts.
/// commitment transaction, thus per_commitment_secret always come from cheater
/// and revocation_base_secret always come from punisher, which is the broadcaster
/// of the transaction spending with this key knowledge.
-///
-/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
-/// generated (ie our own).
-pub fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey) -> Result<SecretKey, SecpError> {
+pub fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>,
+ per_commitment_secret: &SecretKey, countersignatory_revocation_base_secret: &SecretKey)
+-> SecretKey {
let countersignatory_revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &countersignatory_revocation_base_secret);
let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
Sha256::from_engine(sha).into_inner()
};
- let countersignatory_contrib = countersignatory_revocation_base_secret.clone().mul_tweak(&Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())?;
- let broadcaster_contrib = per_commitment_secret.clone().mul_tweak(&Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())?;
+ let countersignatory_contrib = countersignatory_revocation_base_secret.clone().mul_tweak(&Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())
+ .expect("Multiplying a secret key by a hash is expected to never fail per secp256k1 docs");
+ let broadcaster_contrib = per_commitment_secret.clone().mul_tweak(&Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())
+ .expect("Multiplying a secret key by a hash is expected to never fail per secp256k1 docs");
countersignatory_contrib.add_tweak(&Scalar::from_be_bytes(broadcaster_contrib.secret_bytes()).unwrap())
+ .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak commits to the key.")
}
/// Derives a per-commitment-transaction revocation public key from its constituent parts. This is
///
/// Note that this is infallible iff we trust that at least one of the two input keys are randomly
/// generated (ie our own).
-pub fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, countersignatory_revocation_base_point: &PublicKey) -> Result<PublicKey, SecpError> {
+pub fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>,
+ per_commitment_point: &PublicKey, countersignatory_revocation_base_point: &PublicKey)
+-> PublicKey {
let rev_append_commit_hash_key = {
let mut sha = Sha256::engine();
sha.input(&countersignatory_revocation_base_point.serialize());
Sha256::from_engine(sha).into_inner()
};
- let countersignatory_contrib = countersignatory_revocation_base_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())?;
- let broadcaster_contrib = per_commitment_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())?;
+ let countersignatory_contrib = countersignatory_revocation_base_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(rev_append_commit_hash_key).unwrap())
+ .expect("Multiplying a valid public key by a hash is expected to never fail per secp256k1 docs");
+ let broadcaster_contrib = per_commitment_point.clone().mul_tweak(&secp_ctx, &Scalar::from_be_bytes(commit_append_rev_hash_key).unwrap())
+ .expect("Multiplying a valid public key by a hash is expected to never fail per secp256k1 docs");
countersignatory_contrib.combine(&broadcaster_contrib)
+ .expect("Addition only fails if the tweak is the inverse of the key. This is not possible when the tweak commits to the key.")
}
/// The set of public keys which are used in the creation of one commitment transaction.
impl TxCreationKeys {
/// Create per-state keys from channel base points and the per-commitment point.
/// Key set is asymmetric and can't be used as part of counter-signatory set of transactions.
- pub fn derive_new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> Result<TxCreationKeys, SecpError> {
- Ok(TxCreationKeys {
+ pub fn derive_new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, broadcaster_delayed_payment_base: &PublicKey, broadcaster_htlc_base: &PublicKey, countersignatory_revocation_base: &PublicKey, countersignatory_htlc_base: &PublicKey) -> TxCreationKeys {
+ TxCreationKeys {
per_commitment_point: per_commitment_point.clone(),
- revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base)?,
- broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base)?,
- countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base)?,
- broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base)?,
- })
+ revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &countersignatory_revocation_base),
+ broadcaster_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_htlc_base),
+ countersignatory_htlc_key: derive_public_key(&secp_ctx, &per_commitment_point, &countersignatory_htlc_base),
+ broadcaster_delayed_payment_key: derive_public_key(&secp_ctx, &per_commitment_point, &broadcaster_delayed_payment_base),
+ }
}
/// Generate per-state keys from channel static keys.
/// Key set is asymmetric and can't be used as part of counter-signatory set of transactions.
- pub fn from_channel_static_keys<T: secp256k1::Signing + secp256k1::Verification>(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TxCreationKeys, SecpError> {
+ pub fn from_channel_static_keys<T: secp256k1::Signing + secp256k1::Verification>(per_commitment_point: &PublicKey, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> TxCreationKeys {
TxCreationKeys::derive_new(
&secp_ctx,
&per_commitment_point,
pub fn verify<T: secp256k1::Signing + secp256k1::Verification>(&self, channel_parameters: &DirectedChannelTransactionParameters, broadcaster_keys: &ChannelPublicKeys, countersignatory_keys: &ChannelPublicKeys, secp_ctx: &Secp256k1<T>) -> Result<TrustedCommitmentTransaction, ()> {
// This is the only field of the key cache that we trust
let per_commitment_point = self.keys.per_commitment_point;
- let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx).unwrap();
+ let keys = TxCreationKeys::from_channel_static_keys(&per_commitment_point, broadcaster_keys, countersignatory_keys, secp_ctx);
if keys != self.keys {
return Err(());
}
let keys = &inner.keys;
let txid = inner.built.txid;
let mut ret = Vec::with_capacity(inner.htlcs.len());
- let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key).map_err(|_| ())?;
+ let holder_htlc_key = derive_private_key(secp_ctx, &inner.keys.per_commitment_point, htlc_base_key);
for this_htlc in inner.htlcs.iter() {
assert!(this_htlc.transaction_output_index.is_some());
let htlc_basepoint = &signer.pubkeys().htlc_basepoint;
let holder_pubkeys = signer.pubkeys();
let counterparty_pubkeys = counterparty_signer.pubkeys();
- let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint).unwrap();
+ let keys = TxCreationKeys::derive_new(&secp_ctx, &per_commitment_point, delayed_payment_base, htlc_basepoint, &counterparty_pubkeys.revocation_basepoint, &counterparty_pubkeys.htlc_basepoint);
let mut channel_parameters = ChannelTransactionParameters {
holder_pubkeys: holder_pubkeys.clone(),
holder_selected_contest_delay: 0,
projects / rust-lightning / blobdiff