X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Fchain%2Fkeysinterface.rs;h=9a3baea8bb442a3c6928cca83559606a66de95ff;hb=28c9b56113ff1ebb1b505a2c979c55c1626aa06b;hp=33c88cf11e38c672d6394bd3027b89b8664bbf0b;hpb=6587607c5144b8a4930a6cbe6e94b6dc0ceb2f78;p=rust-lightning

diff --git a/lightning/src/chain/keysinterface.rs b/lightning/src/chain/keysinterface.rs
index 33c88cf1..9a3baea8 100644
--- a/lightning/src/chain/keysinterface.rs
+++ b/lightning/src/chain/keysinterface.rs
@@ -27,6 +27,7 @@ use bitcoin::hash_types::WPubkeyHash;
 
 use bitcoin::secp256k1::{SecretKey, PublicKey};
 use bitcoin::secp256k1::{Secp256k1, ecdsa::Signature, Signing};
+use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1::ecdsa::RecoverableSignature;
 use bitcoin::{secp256k1, Witness};
 
@@ -397,11 +398,19 @@ 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) based on the provided [`Recipient`].
+	/// Get node secret key based on the provided [`Recipient`].
+	///
+	/// The node_id/network_key is the public key that corresponds to this secret key.
 	///
 	/// 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, ()>;
+	/// Gets the ECDH shared secret of our [`node secret`] and `other_key`, multiplying by `tweak` if
+	/// one is provided. Note that this tweak can be applied to `other_key` instead of our node
+	/// secret, though this is less efficient.
+	///
+	/// [`node secret`]: Self::get_node_secret
+	fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&[u8; 32]>) -> Result<SharedSecret, ()>;
 	/// 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
@@ -1131,6 +1140,14 @@ impl KeysInterface for KeysManager {
 		}
 	}
 
+	fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&[u8; 32]>) -> Result<SharedSecret, ()> {
+		let mut node_secret = self.get_node_secret(recipient)?;
+		if let Some(tweak) = tweak {
+			node_secret.mul_assign(tweak).map_err(|_| ())?;
+		}
+		Ok(SharedSecret::new(other_key, &node_secret))
+	}
+
 	fn get_inbound_payment_key_material(&self) -> KeyMaterial {
 		self.inbound_payment_key.clone()
 	}
@@ -1215,6 +1232,14 @@ impl KeysInterface for PhantomKeysManager {
 		}
 	}
 
+	fn ecdh(&self, recipient: Recipient, other_key: &PublicKey, tweak: Option<&[u8; 32]>) -> Result<SharedSecret, ()> {
+		let mut node_secret = self.get_node_secret(recipient)?;
+		if let Some(tweak) = tweak {
+			node_secret.mul_assign(tweak).map_err(|_| ())?;
+		}
+		Ok(SharedSecret::new(other_key, &node_secret))
+	}
+
 	fn get_inbound_payment_key_material(&self) -> KeyMaterial {
 		self.inbound_payment_key.clone()
 	}