use bitcoin::secp256k1;
use util::{byte_utils, transaction_utils};
+use util::crypto::hkdf_extract_expand_twice;
use util::ser::{Writeable, Writer, Readable, ReadableArgs};
use chain::transaction::OutPoint;
pub trait Sign: BaseSign + Writeable + Clone {
}
+/// Specifies the recipient of an invoice, to indicate to [`KeysInterface::sign_invoice`] what node
+/// secret key should be used to sign the invoice.
+pub enum Recipient {
+ /// The invoice should be signed with the local node secret key.
+ Node,
+ /// The invoice should be signed with the phantom node secret key. This secret key must be the
+ /// same for all nodes participating in the [phantom node payment].
+ ///
+ /// [phantom node payment]: PhantomKeysManager
+ PhantomNode,
+}
+
/// A trait to describe an object which can get user secrets and key material.
pub trait KeysInterface {
/// A type which implements Sign which will be returned by get_channel_signer.
type Signer : Sign;
- /// Get node secret key (aka node_id or network_key).
+ /// Get node secret key (aka node_id or network_key) based on the provided [`Recipient`].
///
- /// This method must return the same value each time it is called.
- fn get_node_secret(&self) -> SecretKey;
+ /// This method must return the same value each time it is called with a given `Recipient`
+ /// parameter.
+ fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()>;
/// Get a script pubkey which we send funds to when claiming on-chain contestable outputs.
///
/// This method should return a different value each time it is called, to avoid linking
/// this trait to parse the invoice and make sure they're signing what they expect, rather than
/// blindly signing the hash.
/// The hrp is ascii bytes, while the invoice data is base32.
- fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5]) -> Result<RecoverableSignature, ()>;
+ ///
+ /// The secret key used to sign the invoice is dependent on the [`Recipient`].
+ fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], receipient: Recipient) -> Result<RecoverableSignature, ()>;
/// Get secret key material as bytes for use in encrypting and decrypting inbound payment data.
///
+ /// If the implementor of this trait supports [phantom node payments], then every node that is
+ /// intended to be included in the phantom invoice route hints must return the same value from
+ /// this method.
+ // This is because LDK avoids storing inbound payment data by encrypting payment data in the
+ // payment hash and/or payment secret, therefore for a payment to be receivable by multiple
+ // nodes, they must share the key that encrypts this payment data.
+ ///
/// This method must return the same value each time it is called.
+ ///
+ /// [phantom node payments]: PhantomKeysManager
fn get_inbound_payment_key_material(&self) -> KeyMaterial;
}
/// ChannelMonitor closes may use seed/1'
/// Cooperative closes may use seed/2'
/// The two close keys may be needed to claim on-chain funds!
+///
+/// This struct cannot be used for nodes that wish to support receiving phantom payments;
+/// [`PhantomKeysManager`] must be used instead.
+///
+/// Note that switching between this struct and [`PhantomKeysManager`] will invalidate any
+/// previously issued invoices and attempts to pay previous invoices will fail.
pub struct KeysManager {
secp_ctx: Secp256k1<secp256k1::All>,
node_secret: SecretKey,
/// transaction will have a feerate, at least, of the given value.
///
/// Returns `Err(())` if the output value is greater than the input value minus required fee,
- /// if a descriptor was duplicated, or if an output descriptor script_pubkey
+ /// if a descriptor was duplicated, or if an output descriptor `script_pubkey`
/// does not match the one we can spend.
///
/// We do not enforce that outputs meet the dust limit or that any output scripts are standard.
impl KeysInterface for KeysManager {
type Signer = InMemorySigner;
- fn get_node_secret(&self) -> SecretKey {
- self.node_secret.clone()
+ fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
+ match recipient {
+ Recipient::Node => Ok(self.node_secret.clone()),
+ Recipient::PhantomNode => Err(())
+ }
}
fn get_inbound_payment_key_material(&self) -> KeyMaterial {
}
fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
- InMemorySigner::read(&mut io::Cursor::new(reader), self.get_node_secret())
+ InMemorySigner::read(&mut io::Cursor::new(reader), self.node_secret.clone())
+ }
+
+ fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
+ let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
+ let secret = match recipient {
+ Recipient::Node => self.get_node_secret(Recipient::Node)?,
+ Recipient::PhantomNode => return Err(()),
+ };
+ Ok(self.secp_ctx.sign_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
+ }
+}
+
+/// Similar to [`KeysManager`], but allows the node using this struct to receive phantom node
+/// payments.
+///
+/// A phantom node payment is a payment made to a phantom invoice, which is an invoice that can be
+/// paid to one of multiple nodes. This works because we encode the invoice route hints such that
+/// LDK will recognize an incoming payment as destined for a phantom node, and collect the payment
+/// itself without ever needing to forward to this fake node.
+///
+/// Phantom node payments are useful for load balancing between multiple LDK nodes. They also
+/// provide some fault tolerance, because payers will automatically retry paying other provided
+/// nodes in the case that one node goes down.
+///
+/// Note that multi-path payments are not supported in phantom invoices for security reasons.
+// In the hypothetical case that we did support MPP phantom payments, there would be no way for
+// nodes to know when the full payment has been received (and the preimage can be released) without
+// significantly compromising on our safety guarantees. I.e., if we expose the ability for the user
+// to tell LDK when the preimage can be released, we open ourselves to attacks where the preimage
+// is released too early.
+//
+/// Switching between this struct and [`KeysManager`] will invalidate any previously issued
+/// invoices and attempts to pay previous invoices will fail.
+pub struct PhantomKeysManager {
+ inner: KeysManager,
+ inbound_payment_key: KeyMaterial,
+ phantom_secret: SecretKey,
+}
+
+impl KeysInterface for PhantomKeysManager {
+ type Signer = InMemorySigner;
+
+ fn get_node_secret(&self, recipient: Recipient) -> Result<SecretKey, ()> {
+ match recipient {
+ Recipient::Node => self.inner.get_node_secret(Recipient::Node),
+ Recipient::PhantomNode => Ok(self.phantom_secret.clone()),
+ }
+ }
+
+ fn get_inbound_payment_key_material(&self) -> KeyMaterial {
+ self.inbound_payment_key.clone()
+ }
+
+ fn get_destination_script(&self) -> Script {
+ self.inner.get_destination_script()
+ }
+
+ fn get_shutdown_scriptpubkey(&self) -> ShutdownScript {
+ self.inner.get_shutdown_scriptpubkey()
+ }
+
+ fn get_channel_signer(&self, inbound: bool, channel_value_satoshis: u64) -> Self::Signer {
+ self.inner.get_channel_signer(inbound, channel_value_satoshis)
+ }
+
+ fn get_secure_random_bytes(&self) -> [u8; 32] {
+ self.inner.get_secure_random_bytes()
+ }
+
+ fn read_chan_signer(&self, reader: &[u8]) -> Result<Self::Signer, DecodeError> {
+ self.inner.read_chan_signer(reader)
}
- fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5]) -> Result<RecoverableSignature, ()> {
+ fn sign_invoice(&self, hrp_bytes: &[u8], invoice_data: &[u5], recipient: Recipient) -> Result<RecoverableSignature, ()> {
let preimage = construct_invoice_preimage(&hrp_bytes, &invoice_data);
- Ok(self.secp_ctx.sign_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &self.get_node_secret()))
+ let secret = self.get_node_secret(recipient)?;
+ Ok(self.inner.secp_ctx.sign_recoverable(&hash_to_message!(&Sha256::hash(&preimage)), &secret))
+ }
+}
+
+impl PhantomKeysManager {
+ /// Constructs a `PhantomKeysManager` given a 32-byte seed and an additional `cross_node_seed`
+ /// that is shared across all nodes that intend to participate in [phantom node payments] together.
+ ///
+ /// See [`KeysManager::new`] for more information on `seed`, `starting_time_secs`, and
+ /// `starting_time_nanos`.
+ ///
+ /// `cross_node_seed` must be the same across all phantom payment-receiving nodes and also the
+ /// same across restarts, or else inbound payments may fail.
+ ///
+ /// [phantom node payments]: PhantomKeysManager
+ pub fn new(seed: &[u8; 32], starting_time_secs: u64, starting_time_nanos: u32, cross_node_seed: &[u8; 32]) -> Self {
+ let inner = KeysManager::new(seed, starting_time_secs, starting_time_nanos);
+ let (inbound_key, phantom_key) = hkdf_extract_expand_twice(b"LDK Inbound and Phantom Payment Key Expansion", cross_node_seed);
+ Self {
+ inner,
+ inbound_payment_key: KeyMaterial(inbound_key),
+ phantom_secret: SecretKey::from_slice(&phantom_key).unwrap(),
+ }
+ }
+
+ /// See [`KeysManager::spend_spendable_outputs`] for documentation on this method.
+ pub fn spend_spendable_outputs<C: Signing>(&self, descriptors: &[&SpendableOutputDescriptor], outputs: Vec<TxOut>, change_destination_script: Script, feerate_sat_per_1000_weight: u32, secp_ctx: &Secp256k1<C>) -> Result<Transaction, ()> {
+ self.inner.spend_spendable_outputs(descriptors, outputs, change_destination_script, feerate_sat_per_1000_weight, secp_ctx)
+ }
+
+ /// See [`KeysManager::derive_channel_keys`] for documentation on this method.
+ pub fn derive_channel_keys(&self, channel_value_satoshis: u64, params: &[u8; 32]) -> InMemorySigner {
+ self.inner.derive_channel_keys(channel_value_satoshis, params)
}
}
projects / rust-lightning / blobdiff