+++ /dev/null
-// This file is Copyright its original authors, visible in version control
-// history.
-//
-// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
-// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
-// You may not use this file except in accordance with one or both of these
-// licenses.
-
-//! Creating blinded routes and related utilities live here.
-
-use bitcoin::hashes::{Hash, HashEngine};
-use bitcoin::hashes::sha256::Hash as Sha256;
-use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
-
-use crate::chain::keysinterface::{KeysInterface, Recipient};
-use super::packet::ControlTlvs;
-use super::utils;
-use crate::ln::msgs::DecodeError;
-use crate::ln::onion_utils;
-use crate::util::chacha20poly1305rfc::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
-use crate::util::ser::{FixedLengthReader, LengthReadableArgs, Readable, VecWriter, Writeable, Writer};
-
-use core::mem;
-use core::ops::Deref;
-use crate::io::{self, Cursor};
-use crate::prelude::*;
-
-/// Onion messages can be sent and received to blinded routes, which serve to hide the identity of
-/// the recipient.
-#[derive(Clone, Debug, PartialEq)]
-pub struct BlindedPath {
- /// To send to a blinded route, the sender first finds a route to the unblinded
- /// `introduction_node_id`, which can unblind its [`encrypted_payload`] to find out the onion
- /// message's next hop and forward it along.
- ///
- /// [`encrypted_payload`]: BlindedHop::encrypted_payload
- pub(crate) introduction_node_id: PublicKey,
- /// Used by the introduction node to decrypt its [`encrypted_payload`] to forward the onion
- /// message.
- ///
- /// [`encrypted_payload`]: BlindedHop::encrypted_payload
- pub(crate) blinding_point: PublicKey,
- /// The hops composing the blinded route.
- pub(crate) blinded_hops: Vec<BlindedHop>,
-}
-
-/// Used to construct the blinded hops portion of a blinded route. These hops cannot be identified
-/// by outside observers and thus can be used to hide the identity of the recipient.
-#[derive(Clone, Debug, PartialEq)]
-pub struct BlindedHop {
- /// The blinded node id of this hop in a blinded route.
- pub(crate) blinded_node_id: PublicKey,
- /// The encrypted payload intended for this hop in a blinded route.
- // The node sending to this blinded route will later encode this payload into the onion packet for
- // this hop.
- pub(crate) encrypted_payload: Vec<u8>,
-}
-
-impl BlindedPath {
- /// Create a blinded route to be forwarded along `node_pks`. The last node pubkey in `node_pks`
- /// will be the destination node.
- ///
- /// Errors if less than two hops are provided or if `node_pk`(s) are invalid.
- // TODO: make all payloads the same size with padding + add dummy hops
- pub fn new<K: KeysInterface, T: secp256k1::Signing + secp256k1::Verification>
- (node_pks: &[PublicKey], keys_manager: &K, secp_ctx: &Secp256k1<T>) -> Result<Self, ()>
- {
- if node_pks.len() < 2 { return Err(()) }
- let blinding_secret_bytes = keys_manager.get_secure_random_bytes();
- let blinding_secret = SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
- let introduction_node_id = node_pks[0];
-
- Ok(BlindedPath {
- introduction_node_id,
- blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
- blinded_hops: blinded_hops(secp_ctx, node_pks, &blinding_secret).map_err(|_| ())?,
- })
- }
-
- // Advance the blinded route by one hop, so make the second hop into the new introduction node.
- pub(super) fn advance_by_one<K: Deref, T: secp256k1::Signing + secp256k1::Verification>
- (&mut self, keys_manager: &K, secp_ctx: &Secp256k1<T>) -> Result<(), ()>
- where K::Target: KeysInterface
- {
- let control_tlvs_ss = keys_manager.ecdh(Recipient::Node, &self.blinding_point, None)?;
- let rho = onion_utils::gen_rho_from_shared_secret(&control_tlvs_ss.secret_bytes());
- let encrypted_control_tlvs = self.blinded_hops.remove(0).encrypted_payload;
- let mut s = Cursor::new(&encrypted_control_tlvs);
- let mut reader = FixedLengthReader::new(&mut s, encrypted_control_tlvs.len() as u64);
- match ChaChaPolyReadAdapter::read(&mut reader, rho) {
- Ok(ChaChaPolyReadAdapter { readable: ControlTlvs::Forward(ForwardTlvs {
- mut next_node_id, next_blinding_override,
- })}) => {
- let mut new_blinding_point = match next_blinding_override {
- Some(blinding_point) => blinding_point,
- None => {
- let blinding_factor = {
- let mut sha = Sha256::engine();
- sha.input(&self.blinding_point.serialize()[..]);
- sha.input(control_tlvs_ss.as_ref());
- Sha256::from_engine(sha).into_inner()
- };
- self.blinding_point.mul_tweak(secp_ctx, &Scalar::from_be_bytes(blinding_factor).unwrap())
- .map_err(|_| ())?
- }
- };
- mem::swap(&mut self.blinding_point, &mut new_blinding_point);
- mem::swap(&mut self.introduction_node_id, &mut next_node_id);
- Ok(())
- },
- _ => Err(())
- }
- }
-}
-
-/// Construct blinded hops for the given `unblinded_path`.
-fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
- secp_ctx: &Secp256k1<T>, unblinded_path: &[PublicKey], session_priv: &SecretKey
-) -> Result<Vec<BlindedHop>, secp256k1::Error> {
- let mut blinded_hops = Vec::with_capacity(unblinded_path.len());
-
- let mut prev_ss_and_blinded_node_id = None;
- utils::construct_keys_callback(secp_ctx, unblinded_path, None, session_priv, |blinded_node_id, _, _, encrypted_payload_ss, unblinded_pk, _| {
- if let Some((prev_ss, prev_blinded_node_id)) = prev_ss_and_blinded_node_id {
- if let Some(pk) = unblinded_pk {
- let payload = ForwardTlvs {
- next_node_id: pk,
- next_blinding_override: None,
- };
- blinded_hops.push(BlindedHop {
- blinded_node_id: prev_blinded_node_id,
- encrypted_payload: encrypt_payload(payload, prev_ss),
- });
- } else { debug_assert!(false); }
- }
- prev_ss_and_blinded_node_id = Some((encrypted_payload_ss, blinded_node_id));
- })?;
-
- if let Some((final_ss, final_blinded_node_id)) = prev_ss_and_blinded_node_id {
- let final_payload = ReceiveTlvs { path_id: None };
- blinded_hops.push(BlindedHop {
- blinded_node_id: final_blinded_node_id,
- encrypted_payload: encrypt_payload(final_payload, final_ss),
- });
- } else { debug_assert!(false) }
-
- Ok(blinded_hops)
-}
-
-/// Encrypt TLV payload to be used as a [`BlindedHop::encrypted_payload`].
-fn encrypt_payload<P: Writeable>(payload: P, encrypted_tlvs_ss: [u8; 32]) -> Vec<u8> {
- let mut writer = VecWriter(Vec::new());
- let write_adapter = ChaChaPolyWriteAdapter::new(encrypted_tlvs_ss, &payload);
- write_adapter.write(&mut writer).expect("In-memory writes cannot fail");
- writer.0
-}
-
-impl Writeable for BlindedPath {
- fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
- self.introduction_node_id.write(w)?;
- self.blinding_point.write(w)?;
- (self.blinded_hops.len() as u8).write(w)?;
- for hop in &self.blinded_hops {
- hop.write(w)?;
- }
- Ok(())
- }
-}
-
-impl Readable for BlindedPath {
- fn read<R: io::Read>(r: &mut R) -> Result<Self, DecodeError> {
- let introduction_node_id = Readable::read(r)?;
- let blinding_point = Readable::read(r)?;
- let num_hops: u8 = Readable::read(r)?;
- if num_hops == 0 { return Err(DecodeError::InvalidValue) }
- let mut blinded_hops: Vec<BlindedHop> = Vec::with_capacity(num_hops.into());
- for _ in 0..num_hops {
- blinded_hops.push(Readable::read(r)?);
- }
- Ok(BlindedPath {
- introduction_node_id,
- blinding_point,
- blinded_hops,
- })
- }
-}
-
-impl_writeable!(BlindedHop, {
- blinded_node_id,
- encrypted_payload
-});
-
-/// TLVs to encode in an intermediate onion message packet's hop data. When provided in a blinded
-/// route, they are encoded into [`BlindedHop::encrypted_payload`].
-pub(crate) struct ForwardTlvs {
- /// The node id of the next hop in the onion message's path.
- pub(super) next_node_id: PublicKey,
- /// Senders to a blinded route use this value to concatenate the route they find to the
- /// introduction node with the blinded route.
- pub(super) next_blinding_override: Option<PublicKey>,
-}
-
-/// Similar to [`ForwardTlvs`], but these TLVs are for the final node.
-pub(crate) struct ReceiveTlvs {
- /// If `path_id` is `Some`, it is used to identify the blinded route that this onion message is
- /// sending to. This is useful for receivers to check that said blinded route is being used in
- /// the right context.
- pub(super) path_id: Option<[u8; 32]>,
-}
-
-impl Writeable for ForwardTlvs {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
- // TODO: write padding
- encode_tlv_stream!(writer, {
- (4, self.next_node_id, required),
- (8, self.next_blinding_override, option)
- });
- Ok(())
- }
-}
-
-impl Writeable for ReceiveTlvs {
- fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
- // TODO: write padding
- encode_tlv_stream!(writer, {
- (6, self.path_id, option),
- });
- Ok(())
- }
-}
projects / rust-lightning / blobdiff