//! Creating blinded routes and related utilities live here.
-use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
+use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::sha256::Hash as Sha256;
+use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
-use chain::keysinterface::{KeysInterface, Sign};
+use crate::chain::keysinterface::{KeysInterface, Recipient};
+use super::packet::ControlTlvs;
use super::utils;
-use util::chacha20poly1305rfc::ChaChaPolyWriteAdapter;
-use util::ser::{VecWriter, Writeable, Writer};
+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::iter::FromIterator;
-use io;
-use prelude::*;
+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 BlindedRoute {
/// 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(super) introduction_node_id: PublicKey,
+ 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(super) blinding_point: PublicKey,
+ pub(crate) blinding_point: PublicKey,
/// The hops composing the blinded route.
- pub(super) blinded_hops: Vec<BlindedHop>,
+ 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(super) blinded_node_id: PublicKey,
+ 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(super) encrypted_payload: Vec<u8>,
+ pub(crate) encrypted_payload: Vec<u8>,
}
impl BlindedRoute {
///
/// 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<Signer: Sign, K: KeysInterface, T: secp256k1::Signing + secp256k1::Verification>
+ 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(()) }
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`.
writer.0
}
+impl Writeable for BlindedRoute {
+ 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 BlindedRoute {
+ 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(BlindedRoute {
+ 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 {