X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;ds=sidebyside;f=lightning%2Fsrc%2Fblinded_path%2Fmod.rs;h=89087a10cd414ac9fdeae4331490ef97e73666ea;hb=861e0eee9e2461fbb2c21454da746f5def5d39a5;hp=6225f99869b9364c6fadd0f75f437bcafc95536d;hpb=fe5a076aa6aa535c441f56419a680f383fd24744;p=rust-lightning

diff --git a/lightning/src/blinded_path/mod.rs b/lightning/src/blinded_path/mod.rs
index 6225f998..89087a10 100644
--- a/lightning/src/blinded_path/mod.rs
+++ b/lightning/src/blinded_path/mod.rs
@@ -9,6 +9,7 @@
 
 //! Creating blinded paths and related utilities live here.
 
+pub mod payment;
 pub(crate) mod message;
 pub(crate) mod utils;
 
@@ -40,13 +41,14 @@ pub struct BlindedPath {
 	pub blinded_hops: Vec<BlindedHop>,
 }
 
-/// Used to construct the blinded hops portion of a blinded path. These hops cannot be identified
-/// by outside observers and thus can be used to hide the identity of the recipient.
+/// An encrypted payload and node id corresponding to a hop in a payment or onion message path, to
+/// be encoded in the sender's onion packet. These hops cannot be identified by outside observers
+/// and thus can be used to hide the identity of the recipient.
 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
 pub struct BlindedHop {
-	/// The blinded node id of this hop in a blinded path.
+	/// The blinded node id of this hop in a [`BlindedPath`].
 	pub blinded_node_id: PublicKey,
-	/// The encrypted payload intended for this hop in a blinded path.
+	/// The encrypted payload intended for this hop in a [`BlindedPath`].
 	// The node sending to this blinded path will later encode this payload into the onion packet for
 	// this hop.
 	pub encrypted_payload: Vec<u8>,
@@ -72,6 +74,27 @@ impl BlindedPath {
 			blinded_hops: message::blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
 		})
 	}
+
+	/// Create a blinded path for a payment, to be forwarded along `path`. The last node
+	/// in `path` will be the destination node.
+	///
+	/// Errors if `path` is empty or a node id in `path` is invalid.
+	//  TODO: make all payloads the same size with padding + add dummy hops
+	pub fn new_for_payment<ES: EntropySource, T: secp256k1::Signing + secp256k1::Verification>(
+		intermediate_nodes: &[(PublicKey, payment::ForwardTlvs)], payee_node_id: PublicKey,
+		payee_tlvs: payment::ReceiveTlvs, entropy_source: &ES, secp_ctx: &Secp256k1<T>
+	) -> Result<Self, ()> {
+		let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
+		let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
+
+		Ok(BlindedPath {
+			introduction_node_id: intermediate_nodes.first().map_or(payee_node_id, |n| n.0),
+			blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
+			blinded_hops: payment::blinded_hops(
+				secp_ctx, intermediate_nodes, payee_node_id, payee_tlvs, &blinding_secret
+			).map_err(|_| ())?,
+		})
+	}
 }
 
 impl Writeable for BlindedPath {