+//! Various utilities for building scripts and deriving keys related to channels. These are
+//! largely of interest for those implementing chain::keysinterface::ChannelKeys message signing
+//! by hand.
+
use bitcoin::blockdata::script::{Script,Builder};
use bitcoin::blockdata::opcodes;
use bitcoin::blockdata::transaction::{TxIn,TxOut,OutPoint,Transaction};
use secp256k1::Secp256k1;
use secp256k1;
-pub const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
-pub const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
+pub(super) const HTLC_SUCCESS_TX_WEIGHT: u64 = 703;
+pub(super) const HTLC_TIMEOUT_TX_WEIGHT: u64 = 663;
// Various functions for key derivation and transaction creation for use within channels. Primarily
// used in Channel and ChannelMonitor.
-pub fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] {
+pub(super) fn build_commitment_secret(commitment_seed: &[u8; 32], idx: u64) -> [u8; 32] {
let mut res: [u8; 32] = commitment_seed.clone();
for i in 0..48 {
let bitpos = 47 - i;
res
}
+/// Derives a per-commitment-transaction private key (eg an htlc key or payment key) from the base
+/// private key for that type of key and the per_commitment_point (available in TxCreationKeys)
pub fn derive_private_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
Ok(key)
}
-pub fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
+pub
(super) fn derive_public_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
let mut sha = Sha256::engine();
sha.input(&per_commitment_point.serialize());
sha.input(&base_point.serialize());
}
/// Derives a revocation key from its constituent parts
-pub fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, revocation_base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
+pub(super) fn derive_private_revocation_key<T: secp256k1::Signing>(secp_ctx: &Secp256k1<T>, per_commitment_secret: &SecretKey, revocation_base_secret: &SecretKey) -> Result<SecretKey, secp256k1::Error> {
let revocation_base_point = PublicKey::from_secret_key(&secp_ctx, &revocation_base_secret);
let per_commitment_point = PublicKey::from_secret_key(&secp_ctx, &per_commitment_secret);
Ok(part_a)
}
-pub fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, revocation_base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
+pub
(super) fn derive_public_revocation_key<T: secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, revocation_base_point: &PublicKey) -> Result<PublicKey, secp256k1::Error> {
let rev_append_commit_hash_key = {
let mut sha = Sha256::engine();
sha.input(&revocation_base_point.serialize());
part_a.combine(&part_b)
}
+/// The set of public keys which are used in the creation of one commitment transaction.
+/// These are derived from the channel base keys and per-commitment data.
pub struct TxCreationKeys {
+ /// The per-commitment public key which was used to derive the other keys.
pub per_commitment_point: PublicKey,
+ /// The revocation key which is used to allow the owner of the commitment transaction to
+ /// provide their counterparty the ability to punish them if they broadcast an old state.
pub revocation_key: PublicKey,
+ /// A's HTLC Key
pub a_htlc_key: PublicKey,
+ /// B's HTLC Key
pub b_htlc_key: PublicKey,
+ /// A's Payment Key (which isn't allowed to be spent from for some delay)
pub a_delayed_payment_key: PublicKey,
+ /// B's Payment Key
pub b_payment_key: PublicKey,
}
impl TxCreationKeys {
- pub fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
+ pub(super) fn new<T: secp256k1::Signing + secp256k1::Verification>(secp_ctx: &Secp256k1<T>, per_commitment_point: &PublicKey, a_delayed_payment_base: &PublicKey, a_htlc_base: &PublicKey, b_revocation_base: &PublicKey, b_payment_base: &PublicKey, b_htlc_base: &PublicKey) -> Result<TxCreationKeys, secp256k1::Error> {
Ok(TxCreationKeys {
per_commitment_point: per_commitment_point.clone(),
revocation_key: derive_public_revocation_key(&secp_ctx, &per_commitment_point, &b_revocation_base)?,
/// Gets the "to_local" output redeemscript, ie the script which is time-locked or spendable by
/// the revocation key
-pub fn get_revokeable_redeemscript(revocation_key: &PublicKey, to_self_delay: u16, delayed_payment_key: &PublicKey) -> Script {
+pub(super) fn get_revokeable_redeemscript(revocation_key: &PublicKey, to_self_delay: u16, delayed_payment_key: &PublicKey) -> Script {
Builder::new().push_opcode(opcodes::all::OP_IF)
.push_slice(&revocation_key.serialize())
.push_opcode(opcodes::all::OP_ELSE)
}
#[derive(Clone, PartialEq)]
+/// Information about an HTLC as it appears in a commitment transaction
pub struct HTLCOutputInCommitment {
+ /// Whether the HTLC was "offered" (ie outbound in relation to this commitment transaction).
+ /// Note that this is not the same as whether it is ountbound *from us*. To determine that you
+ /// need to compare this value to whether the commitment transaction in question is that of
+ /// the remote party or our own.
pub offered: bool,
+ /// The value, in msat, of the HTLC. The value as it appears in the commitment transaction is
+ /// this divided by 1000.
pub amount_msat: u64,
+ /// The CLTV lock-time at which this HTLC expires.
pub cltv_expiry: u32,
+ /// The hash of the preimage which unlocks this HTLC.
pub payment_hash: PaymentHash,
+ /// The position within the commitment transactions' outputs. This may be None if the value is
+ /// below the dust limit (in which case no output appears in the commitment transaction and the
+ /// value is spent to additional transaction fees).
pub transaction_output_index: Option<u32>,
}
#[inline]
-pub fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
+pub(super) fn get_htlc_redeemscript_with_explicit_keys(htlc: &HTLCOutputInCommitment, a_htlc_key: &PublicKey, b_htlc_key: &PublicKey, revocation_key: &PublicKey) -> Script {
let payment_hash160 = Ripemd160::hash(&htlc.payment_hash.0[..]).into_inner();
if htlc.offered {
Builder::new().push_opcode(opcodes::all::OP_DUP)
projects / rust-lightning / blobdiff