diff --git a/fuzz/src/chanmon_consistency.rs b/fuzz/src/chanmon_consistency.rs
index 8b41c53a635..1439e11da6c 100644
--- a/fuzz/src/chanmon_consistency.rs
+++ b/fuzz/src/chanmon_consistency.rs
@@ -326,7 +326,7 @@ impl NodeSigner for KeyProvider {
 		Ok(SharedSecret::new(other_key, &node_secret))
 	}
 
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
+	fn get_expanded_key(&self) -> ExpandedKey {
 		#[rustfmt::skip]
 		let random_bytes = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, self.node_secret[31]];
 		ExpandedKey::new(random_bytes)
diff --git a/fuzz/src/full_stack.rs b/fuzz/src/full_stack.rs
index 5281a933526..435bb24dae1 100644
--- a/fuzz/src/full_stack.rs
+++ b/fuzz/src/full_stack.rs
@@ -405,7 +405,7 @@ impl NodeSigner for KeyProvider {
 		Ok(SharedSecret::new(other_key, &node_secret))
 	}
 
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
+	fn get_expanded_key(&self) -> ExpandedKey {
 		self.inbound_payment_key
 	}
 
diff --git a/fuzz/src/onion_message.rs b/fuzz/src/onion_message.rs
index a5782dacd42..fd3294fab28 100644
--- a/fuzz/src/onion_message.rs
+++ b/fuzz/src/onion_message.rs
@@ -228,7 +228,7 @@ impl NodeSigner for KeyProvider {
 		Ok(SharedSecret::new(other_key, &node_secret))
 	}
 
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
+	fn get_expanded_key(&self) -> ExpandedKey {
 		unreachable!()
 	}
 
diff --git a/lightning-background-processor/src/lib.rs b/lightning-background-processor/src/lib.rs
index 239ff3f0c98..3a03f96679d 100644
--- a/lightning-background-processor/src/lib.rs
+++ b/lightning-background-processor/src/lib.rs
@@ -1174,7 +1174,7 @@ mod tests {
 	use lightning::routing::gossip::{NetworkGraph, P2PGossipSync};
 	use lightning::routing::router::{CandidateRouteHop, DefaultRouter, Path, RouteHop};
 	use lightning::routing::scoring::{ChannelUsage, LockableScore, ScoreLookUp, ScoreUpdate};
-	use lightning::sign::{ChangeDestinationSourceSync, InMemorySigner, KeysManager};
+	use lightning::sign::{ChangeDestinationSourceSync, InMemorySigner, KeysManager, NodeSigner};
 	use lightning::types::features::{ChannelFeatures, NodeFeatures};
 	use lightning::types::payment::PaymentHash;
 	use lightning::util::config::UserConfig;
@@ -1650,6 +1650,7 @@ mod tests {
 			let msg_router = Arc::new(DefaultMessageRouter::new(
 				network_graph.clone(),
 				Arc::clone(&keys_manager),
+				keys_manager.get_expanded_key(),
 			));
 			let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Bitcoin));
 			let kv_store =
diff --git a/lightning-liquidity/tests/common/mod.rs b/lightning-liquidity/tests/common/mod.rs
index 2259d1eae06..f2639685e64 100644
--- a/lightning-liquidity/tests/common/mod.rs
+++ b/lightning-liquidity/tests/common/mod.rs
@@ -24,7 +24,7 @@ use lightning::onion_message::messenger::DefaultMessageRouter;
 use lightning::routing::gossip::{NetworkGraph, P2PGossipSync};
 use lightning::routing::router::{CandidateRouteHop, DefaultRouter, Path};
 use lightning::routing::scoring::{ChannelUsage, ScoreLookUp, ScoreUpdate};
-use lightning::sign::{InMemorySigner, KeysManager};
+use lightning::sign::{InMemorySigner, KeysManager, NodeSigner};
 use lightning::util::config::UserConfig;
 use lightning::util::persist::{
 	KVStore, CHANNEL_MANAGER_PERSISTENCE_KEY, CHANNEL_MANAGER_PERSISTENCE_PRIMARY_NAMESPACE,
@@ -418,8 +418,11 @@ pub(crate) fn create_liquidity_node(
 		scorer.clone(),
 		Default::default(),
 	));
-	let msg_router =
-		Arc::new(DefaultMessageRouter::new(Arc::clone(&network_graph), Arc::clone(&keys_manager)));
+	let msg_router = Arc::new(DefaultMessageRouter::new(
+		Arc::clone(&network_graph),
+		Arc::clone(&keys_manager),
+		keys_manager.get_expanded_key(),
+	));
 	let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Bitcoin));
 	let kv_store =
 		Arc::new(FilesystemStore::new(format!("{}_persister_{}", &persist_dir, i).into()));
diff --git a/lightning/src/blinded_path/message.rs b/lightning/src/blinded_path/message.rs
index 0e3977ab68e..8e2afa13e73 100644
--- a/lightning/src/blinded_path/message.rs
+++ b/lightning/src/blinded_path/message.rs
@@ -11,6 +11,7 @@
 
 use bitcoin::secp256k1::{self, PublicKey, Secp256k1, SecretKey};
 
+use crate::offers::signer;
 #[allow(unused_imports)]
 use crate::prelude::*;
 
@@ -19,9 +20,9 @@ use crate::blinded_path::{BlindedHop, BlindedPath, Direction, IntroductionNode,
 use crate::crypto::streams::ChaChaPolyReadAdapter;
 use crate::io;
 use crate::io::Cursor;
-use crate::ln::channelmanager::PaymentId;
+use crate::ln::channelmanager::{PaymentId, Verification};
 use crate::ln::msgs::DecodeError;
-use crate::ln::onion_utils;
+use crate::ln::{inbound_payment, onion_utils};
 use crate::offers::nonce::Nonce;
 use crate::onion_message::packet::ControlTlvs;
 use crate::routing::gossip::{NodeId, ReadOnlyNetworkGraph};
@@ -68,7 +69,6 @@ impl BlindedMessagePath {
 	/// pubkey in `node_pks` will be the destination node.
 	///
 	/// Errors if no 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<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
 		intermediate_nodes: &[MessageForwardNode], recipient_node_id: PublicKey,
 		context: MessageContext, entropy_source: ES, secp_ctx: &Secp256k1<T>,
@@ -88,9 +88,53 @@ impl BlindedMessagePath {
 			blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
 			blinded_hops: blinded_hops(
 				secp_ctx,
+				entropy_source,
+				None,
 				intermediate_nodes,
 				recipient_node_id,
 				context,
+				0,
+				&blinding_secret,
+			)
+			.map_err(|_| ())?,
+		}))
+	}
+
+	/// Create a path for an onion message, to be forwarded along `node_pks`.
+	///
+	/// Additionally allows appending a number of dummy hops before the final hop,
+	/// increasing the total path length and enhancing privacy by obscuring the true
+	/// distance between sender and recipient.
+	///
+	/// The last node pubkey in `node_pks` will be the destination node.
+	///
+	/// Errors if no hops are provided or if `node_pk`(s) are invalid.
+	pub fn new_with_dummy_hops<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
+		intermediate_nodes: &[MessageForwardNode], dummy_hops_count: u8,
+		recipient_node_id: PublicKey, context: MessageContext, entropy_source: ES,
+		expanded_key: &inbound_payment::ExpandedKey, secp_ctx: &Secp256k1<T>,
+	) -> Result<Self, ()>
+	where
+		ES::Target: EntropySource,
+	{
+		let introduction_node = IntroductionNode::NodeId(
+			intermediate_nodes.first().map_or(recipient_node_id, |n| n.node_id),
+		);
+		let blinding_secret_bytes = entropy_source.get_secure_random_bytes();
+		let blinding_secret =
+			SecretKey::from_slice(&blinding_secret_bytes[..]).expect("RNG is busted");
+
+		Ok(Self(BlindedPath {
+			introduction_node,
+			blinding_point: PublicKey::from_secret_key(secp_ctx, &blinding_secret),
+			blinded_hops: blinded_hops(
+				secp_ctx,
+				entropy_source,
+				Some(expanded_key),
+				intermediate_nodes,
+				recipient_node_id,
+				context,
+				dummy_hops_count,
 				&blinding_secret,
 			)
 			.map_err(|_| ())?,
@@ -258,6 +302,94 @@ pub(crate) struct ForwardTlvs {
 	pub(crate) next_blinding_override: Option<PublicKey>,
 }
 
+/// Represents a dummy TLV that can be used in a blinded path to extend the path length.
+/// The first dummy TLV is authenticated and contains an HMAC, while subsequent dummy TLVs are
+/// empty and do not contain any data. This allows for the path length to be extended without
+/// adding any additional data, while still ensuring that the path is legitimate and terminates
+/// in valid [`ReceiveTlvs`] data.
+pub(crate) enum DummyTlv {
+	/// The first dummy TLV, which contains an HMAC and is authenticated.
+	/// This TLV is used to ensure that the path is legitimate and terminates in valid
+	/// [`ReceiveTlvs`] data.
+	Primary(PrimaryDummyTlv),
+	/// Subsequent dummy TLVs, which are empty and do not contain any data.
+	/// These TLVs are used to extend the path length without adding any additional data.
+	Subsequent,
+}
+
+impl Writeable for DummyTlv {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+		match self {
+			DummyTlv::Primary(primary) => primary.write(writer)?,
+			DummyTlv::Subsequent => {
+				// Subsequent dummy TLVs are empty, so we don't write anything.
+				// This is to ensure that the path length can be extended without
+				// adding any additional data.
+				encode_tlv_stream!(writer, {
+					(65541, (), required), // Represents that this is a Dummy Tlv variant
+				})
+			},
+		}
+		Ok(())
+	}
+}
+
+/// Represents the first dummy TLV in a blinded path, which is authenticated and contains an HMAC.
+/// These TLV are intended for the final node.
+///
+/// ## Authentication
+/// Authentication provides an additional layer of security, ensuring that the path is legitimate
+/// and terminates in valid [`ReceiveTlvs`] data. Verification begins with the first dummy hop and
+/// continues recursively until the final [`ReceiveTlvs`] is reached.
+///
+/// This prevents an attacker from crafting a bogus blinded path consisting solely of dummy tlv
+/// without any valid payload, which could otherwise waste resources through recursive
+/// processing — a potential vector for DoS-like attacks.
+pub(crate) struct PrimaryDummyTlv {
+	/// The dummy TLV that holds the empty data for the Dummy Hop.
+	pub(crate) dummy_tlv: UnauthenticatedDummyTlv,
+	/// An HMAC of `tlvs` along with a nonce used to construct it.
+	pub(crate) authentication: (Hmac<Sha256>, Nonce),
+}
+
+impl Writeable for PrimaryDummyTlv {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+		encode_tlv_stream!(writer, {
+			(65539, self.authentication, required),
+			// The Some(()) represents that this is a Dummy Tlv variant
+			(65541, (), required),
+		});
+
+		Ok(())
+	}
+}
+
+/// A blank struct, representing a dummy TLV prior to authentication.
+///
+/// For more details, see [`PrimaryDummyTlv`].
+pub(crate) struct UnauthenticatedDummyTlv {}
+
+impl Writeable for UnauthenticatedDummyTlv {
+	fn write<W: Writer>(&self, _writer: &mut W) -> Result<(), io::Error> {
+		Ok(())
+	}
+}
+
+impl Verification for UnauthenticatedDummyTlv {
+	/// Constructs an HMAC to include in [`OffersContext`] for the data along with the given
+	/// [`Nonce`].
+	fn hmac_data(&self, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey) -> Hmac<Sha256> {
+		signer::hmac_for_dummy_tlv(self, nonce, expanded_key)
+	}
+
+	/// Authenticates the data using an HMAC and a [`Nonce`] taken from an [`OffersContext`].
+	fn verify_data(
+		&self, hmac: Hmac<Sha256>, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
+	) -> Result<(), ()> {
+		signer::verify_dummy_tlv(self, hmac, nonce, expanded_key)
+	}
+}
+
 /// Similar to [`ForwardTlvs`], but these TLVs are for the final node.
 pub(crate) struct ReceiveTlvs {
 	/// If `context` is `Some`, it is used to identify the blinded path that this onion message is
@@ -505,13 +637,23 @@ impl_writeable_tlv_based!(DNSResolverContext, {
 pub(crate) const MESSAGE_PADDING_ROUND_OFF: usize = 100;
 
 /// Construct blinded onion message hops for the given `intermediate_nodes` and `recipient_node_id`.
-pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
-	secp_ctx: &Secp256k1<T>, intermediate_nodes: &[MessageForwardNode],
-	recipient_node_id: PublicKey, context: MessageContext, session_priv: &SecretKey,
-) -> Result<Vec<BlindedHop>, secp256k1::Error> {
+pub(super) fn blinded_hops<ES: Deref, T: secp256k1::Signing + secp256k1::Verification>(
+	secp_ctx: &Secp256k1<T>, entropy_source: ES,
+	expanded_key: Option<&inbound_payment::ExpandedKey>, intermediate_nodes: &[MessageForwardNode],
+	recipient_node_id: PublicKey, context: MessageContext, dummy_hops_count: u8,
+	session_priv: &SecretKey,
+) -> Result<Vec<BlindedHop>, secp256k1::Error>
+where
+	ES::Target: EntropySource,
+{
+	if expanded_key.is_none() && dummy_hops_count > 0 {
+		debug_assert!(false, "Dummy hops are not supported without expanded keys");
+	}
+
 	let pks = intermediate_nodes
 		.iter()
 		.map(|node| node.node_id)
+		.chain((0..dummy_hops_count).map(|_| recipient_node_id))
 		.chain(core::iter::once(recipient_node_id));
 	let is_compact = intermediate_nodes.iter().any(|node| node.short_channel_id.is_some());
 
@@ -526,6 +668,14 @@ pub(super) fn blinded_hops<T: secp256k1::Signing + secp256k1::Verification>(
 		.map(|next_hop| {
 			ControlTlvs::Forward(ForwardTlvs { next_hop, next_blinding_override: None })
 		})
+		.chain((0..1).filter(|_| dummy_hops_count > 0).map(|_| {
+			let dummy_tlv = UnauthenticatedDummyTlv {};
+			let nonce = Nonce::from_entropy_source(&*entropy_source);
+			let hmac = dummy_tlv.hmac_data(nonce, expanded_key.unwrap());
+			let tlv = PrimaryDummyTlv { dummy_tlv, authentication: (hmac, nonce) };
+			ControlTlvs::Dummy(DummyTlv::Primary(tlv))
+		}))
+		.chain((1..dummy_hops_count).map(|_| ControlTlvs::Dummy(DummyTlv::Subsequent)))
 		.chain(core::iter::once(ControlTlvs::Receive(ReceiveTlvs { context: Some(context) })));
 
 	if is_compact {
diff --git a/lightning/src/blinded_path/payment.rs b/lightning/src/blinded_path/payment.rs
index f015886933a..ae26d51b1f2 100644
--- a/lightning/src/blinded_path/payment.rs
+++ b/lightning/src/blinded_path/payment.rs
@@ -351,10 +351,7 @@ impl UnauthenticatedReceiveTlvs {
 	/// Creates an authenticated [`ReceiveTlvs`], which includes an HMAC and the provide [`Nonce`]
 	/// that can be use later to verify it authenticity.
 	pub fn authenticate(self, nonce: Nonce, expanded_key: &ExpandedKey) -> ReceiveTlvs {
-		ReceiveTlvs {
-			authentication: (self.hmac_for_offer_payment(nonce, expanded_key), nonce),
-			tlvs: self,
-		}
+		ReceiveTlvs { authentication: (self.hmac_data(nonce, expanded_key), nonce), tlvs: self }
 	}
 }
 
diff --git a/lightning/src/ln/async_payments_tests.rs b/lightning/src/ln/async_payments_tests.rs
index a956f2ebae2..9277775b38d 100644
--- a/lightning/src/ln/async_payments_tests.rs
+++ b/lightning/src/ln/async_payments_tests.rs
@@ -668,7 +668,7 @@ fn amount_doesnt_match_invreq() {
 			valid_invreq = Some(invoice_request.clone());
 			*invoice_request = offer
 				.request_invoice(
-					&nodes[0].keys_manager.get_inbound_payment_key(),
+					&nodes[0].keys_manager.get_expanded_key(),
 					Nonce::from_entropy_source(nodes[0].keys_manager),
 					&secp_ctx,
 					payment_id,
diff --git a/lightning/src/ln/blinded_payment_tests.rs b/lightning/src/ln/blinded_payment_tests.rs
index 18a1089d647..43de09a936c 100644
--- a/lightning/src/ln/blinded_payment_tests.rs
+++ b/lightning/src/ln/blinded_payment_tests.rs
@@ -83,7 +83,7 @@ pub fn blinded_payment_path(
 	};
 
 	let nonce = Nonce([42u8; 16]);
-	let expanded_key = keys_manager.get_inbound_payment_key();
+	let expanded_key = keys_manager.get_expanded_key();
 	let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 
 	let mut secp_ctx = Secp256k1::new();
@@ -168,7 +168,7 @@ fn do_one_hop_blinded_path(success: bool) {
 		payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
 	};
 	let nonce = Nonce([42u8; 16]);
-	let expanded_key = chanmon_cfgs[1].keys_manager.get_inbound_payment_key();
+	let expanded_key = chanmon_cfgs[1].keys_manager.get_expanded_key();
 	let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 
 	let mut secp_ctx = Secp256k1::new();
@@ -222,7 +222,7 @@ fn mpp_to_one_hop_blinded_path() {
 		payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
 	};
 	let nonce = Nonce([42u8; 16]);
-	let expanded_key = chanmon_cfgs[3].keys_manager.get_inbound_payment_key();
+	let expanded_key = chanmon_cfgs[3].keys_manager.get_expanded_key();
 	let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 	let blinded_path = BlindedPaymentPath::new(
 		&[], nodes[3].node.get_our_node_id(), payee_tlvs, u64::MAX, TEST_FINAL_CLTV as u16,
@@ -1342,7 +1342,7 @@ fn custom_tlvs_to_blinded_path() {
 		payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
 	};
 	let nonce = Nonce([42u8; 16]);
-	let expanded_key = chanmon_cfgs[1].keys_manager.get_inbound_payment_key();
+	let expanded_key = chanmon_cfgs[1].keys_manager.get_expanded_key();
 	let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 	let mut secp_ctx = Secp256k1::new();
 	let blinded_path = BlindedPaymentPath::new(
@@ -1396,7 +1396,7 @@ fn fails_receive_tlvs_authentication() {
 		payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
 	};
 	let nonce = Nonce([42u8; 16]);
-	let expanded_key = chanmon_cfgs[1].keys_manager.get_inbound_payment_key();
+	let expanded_key = chanmon_cfgs[1].keys_manager.get_expanded_key();
 	let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 
 	let mut secp_ctx = Secp256k1::new();
@@ -1622,7 +1622,7 @@ fn route_blinding_spec_test_vector() {
 			}
 			Ok(SharedSecret::new(other_key, &node_secret))
 		}
-		fn get_inbound_payment_key(&self) -> ExpandedKey { unreachable!() }
+		fn get_expanded_key(&self) -> ExpandedKey { unreachable!() }
 		fn get_node_id(&self, _recipient: Recipient) -> Result<PublicKey, ()> { unreachable!() }
 		fn sign_invoice(
 			&self, _invoice: &RawBolt11Invoice, _recipient: Recipient,
@@ -1931,7 +1931,7 @@ fn test_trampoline_inbound_payment_decoding() {
 			}
 			Ok(SharedSecret::new(other_key, &node_secret))
 		}
-		fn get_inbound_payment_key(&self) -> ExpandedKey { unreachable!() }
+		fn get_expanded_key(&self) -> ExpandedKey { unreachable!() }
 		fn get_node_id(&self, _recipient: Recipient) -> Result<PublicKey, ()> { unreachable!() }
 		fn sign_invoice(
 			&self, _invoice: &RawBolt11Invoice, _recipient: Recipient,
@@ -2016,7 +2016,7 @@ fn do_test_trampoline_single_hop_receive(success: bool) {
 		};
 
 		let nonce = Nonce([42u8; 16]);
-		let expanded_key = nodes[2].keys_manager.get_inbound_payment_key();
+		let expanded_key = nodes[2].keys_manager.get_expanded_key();
 		let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 		let carol_unblinded_tlvs = payee_tlvs.encode();
 
diff --git a/lightning/src/ln/channelmanager.rs b/lightning/src/ln/channelmanager.rs
index 170d8261d5a..71285938c6b 100644
--- a/lightning/src/ln/channelmanager.rs
+++ b/lightning/src/ln/channelmanager.rs
@@ -256,7 +256,7 @@ pub enum PendingHTLCRouting {
 		requires_blinded_error: bool,
 		/// Set if we are receiving a keysend to a blinded path, meaning we created the
 		/// [`PaymentSecret`] and should verify it using our
-		/// [`NodeSigner::get_inbound_payment_key`].
+		/// [`NodeSigner::get_expanded_key`].
 		has_recipient_created_payment_secret: bool,
 		/// The [`InvoiceRequest`] associated with the [`Offer`] corresponding to this payment.
 		invoice_request: Option<InvoiceRequest>,
@@ -475,12 +475,12 @@ impl Ord for ClaimableHTLC {
 pub trait Verification {
 	/// Constructs an HMAC to include in [`OffersContext`] for the data along with the given
 	/// [`Nonce`].
-	fn hmac_for_offer_payment(
+	fn hmac_data(
 		&self, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Hmac<Sha256>;
 
 	/// Authenticates the data using an HMAC and a [`Nonce`] taken from an [`OffersContext`].
-	fn verify_for_offer_payment(
+	fn verify_data(
 		&self, hmac: Hmac<Sha256>, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Result<(), ()>;
 }
@@ -488,7 +488,7 @@ pub trait Verification {
 impl Verification for PaymentHash {
 	/// Constructs an HMAC to include in [`OffersContext::InboundPayment`] for the payment hash
 	/// along with the given [`Nonce`].
-	fn hmac_for_offer_payment(
+	fn hmac_data(
 		&self, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Hmac<Sha256> {
 		signer::hmac_for_payment_hash(*self, nonce, expanded_key)
@@ -496,7 +496,7 @@ impl Verification for PaymentHash {
 
 	/// Authenticates the payment id using an HMAC and a [`Nonce`] taken from an
 	/// [`OffersContext::InboundPayment`].
-	fn verify_for_offer_payment(
+	fn verify_data(
 		&self, hmac: Hmac<Sha256>, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Result<(), ()> {
 		signer::verify_payment_hash(*self, hmac, nonce, expanded_key)
@@ -504,13 +504,13 @@ impl Verification for PaymentHash {
 }
 
 impl Verification for UnauthenticatedReceiveTlvs {
-	fn hmac_for_offer_payment(
+	fn hmac_data(
 		&self, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Hmac<Sha256> {
 		signer::hmac_for_payment_tlvs(self, nonce, expanded_key)
 	}
 
-	fn verify_for_offer_payment(
+	fn verify_data(
 		&self, hmac: Hmac<Sha256>, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Result<(), ()> {
 		signer::verify_payment_tlvs(self, hmac, nonce, expanded_key)
@@ -550,7 +550,7 @@ impl PaymentId {
 impl Verification for PaymentId {
 	/// Constructs an HMAC to include in [`OffersContext::OutboundPayment`] for the payment id
 	/// along with the given [`Nonce`].
-	fn hmac_for_offer_payment(
+	fn hmac_data(
 		&self, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Hmac<Sha256> {
 		signer::hmac_for_offer_payment_id(*self, nonce, expanded_key)
@@ -558,7 +558,7 @@ impl Verification for PaymentId {
 
 	/// Authenticates the payment id using an HMAC and a [`Nonce`] taken from an
 	/// [`OffersContext::OutboundPayment`].
-	fn verify_for_offer_payment(
+	fn verify_data(
 		&self, hmac: Hmac<Sha256>, nonce: Nonce, expanded_key: &inbound_payment::ExpandedKey,
 	) -> Result<(), ()> {
 		signer::verify_offer_payment_id(*self, hmac, nonce, expanded_key)
@@ -3576,7 +3576,7 @@ where
 	) -> Self {
 		let mut secp_ctx = Secp256k1::new();
 		secp_ctx.seeded_randomize(&entropy_source.get_secure_random_bytes());
-		let expanded_inbound_key = node_signer.get_inbound_payment_key();
+		let expanded_inbound_key = node_signer.get_expanded_key();
 		ChannelManager {
 			default_configuration: config.clone(),
 			chain_hash: ChainHash::using_genesis_block(params.network),
@@ -10560,7 +10560,7 @@ where
 		};
 		let invoice_request = builder.build_and_sign()?;
 
-		let hmac = payment_id.hmac_for_offer_payment(nonce, expanded_key);
+		let hmac = payment_id.hmac_data(nonce, expanded_key);
 		let context = MessageContext::Offers(
 			OffersContext::OutboundPayment { payment_id, nonce, hmac: Some(hmac) }
 		);
@@ -10664,7 +10664,7 @@ where
 				let invoice = builder.allow_mpp().build_and_sign(secp_ctx)?;
 
 				let nonce = Nonce::from_entropy_source(entropy);
-				let hmac = payment_hash.hmac_for_offer_payment(nonce, expanded_key);
+				let hmac = payment_hash.hmac_data(nonce, expanded_key);
 				let context = MessageContext::Offers(OffersContext::InboundPayment {
 					payment_hash: invoice.payment_hash(), nonce, hmac
 				});
@@ -12444,7 +12444,7 @@ where
 			.release_invoice_requests_awaiting_invoice()
 		{
 			let RetryableInvoiceRequest { invoice_request, nonce, .. } = retryable_invoice_request;
-			let hmac = payment_id.hmac_for_offer_payment(nonce, &self.inbound_payment_key);
+			let hmac = payment_id.hmac_data(nonce, &self.inbound_payment_key);
 			let context = MessageContext::Offers(OffersContext::OutboundPayment {
 				payment_id,
 				nonce,
@@ -12627,7 +12627,7 @@ where
 				match response {
 					Ok(invoice) => {
 						let nonce = Nonce::from_entropy_source(&*self.entropy_source);
-						let hmac = payment_hash.hmac_for_offer_payment(nonce, expanded_key);
+						let hmac = payment_hash.hmac_data(nonce, expanded_key);
 						let context = MessageContext::Offers(OffersContext::InboundPayment { payment_hash, nonce, hmac });
 						Some((OffersMessage::Invoice(invoice), responder.respond_with_reply_path(context)))
 					},
@@ -12664,7 +12664,7 @@ where
 			OffersMessage::StaticInvoice(invoice) => {
 				let payment_id = match context {
 					Some(OffersContext::OutboundPayment { payment_id, nonce, hmac: Some(hmac) }) => {
-						if payment_id.verify_for_offer_payment(hmac, nonce, expanded_key).is_err() {
+						if payment_id.verify_data(hmac, nonce, expanded_key).is_err() {
 							return None
 						}
 						payment_id
@@ -12677,7 +12677,7 @@ where
 			OffersMessage::InvoiceError(invoice_error) => {
 				let payment_hash = match context {
 					Some(OffersContext::InboundPayment { payment_hash, nonce, hmac }) => {
-						match payment_hash.verify_for_offer_payment(hmac, nonce, expanded_key) {
+						match payment_hash.verify_data(hmac, nonce, expanded_key) {
 							Ok(_) => Some(payment_hash),
 							Err(_) => None,
 						}
@@ -12690,7 +12690,7 @@ where
 
 				match context {
 					Some(OffersContext::OutboundPayment { payment_id, nonce, hmac: Some(hmac) }) => {
-						if let Ok(()) = payment_id.verify_for_offer_payment(hmac, nonce, expanded_key) {
+						if let Ok(()) = payment_id.verify_data(hmac, nonce, expanded_key) {
 							self.abandon_payment_with_reason(
 								payment_id, PaymentFailureReason::InvoiceRequestRejected,
 							);
@@ -14569,7 +14569,7 @@ where
 			}, None));
 		}
 
-		let expanded_inbound_key = args.node_signer.get_inbound_payment_key();
+		let expanded_inbound_key = args.node_signer.get_expanded_key();
 
 		let mut claimable_payments = hash_map_with_capacity(claimable_htlcs_list.len());
 		if let Some(purposes) = claimable_htlc_purposes {
diff --git a/lightning/src/ln/functional_test_utils.rs b/lightning/src/ln/functional_test_utils.rs
index 8a9a5cb1762..6ac40d1897b 100644
--- a/lightning/src/ln/functional_test_utils.rs
+++ b/lightning/src/ln/functional_test_utils.rs
@@ -29,7 +29,7 @@ use crate::onion_message::messenger::OnionMessenger;
 use crate::ln::onion_utils::LocalHTLCFailureReason;
 use crate::routing::gossip::{P2PGossipSync, NetworkGraph, NetworkUpdate};
 use crate::routing::router::{self, PaymentParameters, Route, RouteParameters};
-use crate::sign::{EntropySource, RandomBytes};
+use crate::sign::{EntropySource, NodeSigner, RandomBytes};
 use crate::util::config::{MaxDustHTLCExposure, UserConfig};
 use crate::util::logger::Logger;
 use crate::util::scid_utils;
@@ -725,7 +725,7 @@ impl<'a, 'b, 'c> Drop for Node<'a, 'b, 'c> {
 					signer_provider: self.keys_manager,
 					fee_estimator: &test_utils::TestFeeEstimator::new(253),
 					router: &test_utils::TestRouter::new(Arc::clone(&network_graph), &self.logger, &scorer),
-					message_router: &test_utils::TestMessageRouter::new(network_graph, self.keys_manager),
+					message_router: &test_utils::TestMessageRouter::new(network_graph, self.keys_manager, self.keys_manager.get_expanded_key()),
 					chain_monitor: self.chain_monitor,
 					tx_broadcaster: &broadcaster,
 					logger: &self.logger,
@@ -3347,13 +3347,14 @@ pub fn create_node_cfgs_with_persisters<'a>(node_count: usize, chanmon_cfgs: &'a
 		let chain_monitor = test_utils::TestChainMonitor::new(Some(&chanmon_cfgs[i].chain_source), &chanmon_cfgs[i].tx_broadcaster, &chanmon_cfgs[i].logger, &chanmon_cfgs[i].fee_estimator, persisters[i], &chanmon_cfgs[i].keys_manager);
 		let network_graph = Arc::new(NetworkGraph::new(Network::Testnet, &chanmon_cfgs[i].logger));
 		let seed = [i as u8; 32];
+		let expanded_key = chanmon_cfgs[i].keys_manager.get_expanded_key();
 		nodes.push(NodeCfg {
 			chain_source: &chanmon_cfgs[i].chain_source,
 			logger: &chanmon_cfgs[i].logger,
 			tx_broadcaster: &chanmon_cfgs[i].tx_broadcaster,
 			fee_estimator: &chanmon_cfgs[i].fee_estimator,
 			router: test_utils::TestRouter::new(network_graph.clone(), &chanmon_cfgs[i].logger, &chanmon_cfgs[i].scorer),
-			message_router: test_utils::TestMessageRouter::new(network_graph.clone(), &chanmon_cfgs[i].keys_manager),
+			message_router: test_utils::TestMessageRouter::new(network_graph.clone(), &chanmon_cfgs[i].keys_manager, expanded_key),
 			chain_monitor,
 			keys_manager: &chanmon_cfgs[i].keys_manager,
 			node_seed: seed,
diff --git a/lightning/src/ln/functional_tests.rs b/lightning/src/ln/functional_tests.rs
index 0c0bb0713cb..2130819a5a9 100644
--- a/lightning/src/ln/functional_tests.rs
+++ b/lightning/src/ln/functional_tests.rs
@@ -50,7 +50,7 @@ use crate::routing::gossip::{NetworkGraph, NetworkUpdate};
 use crate::routing::router::{
 	get_route, Path, PaymentParameters, Route, RouteHop, RouteParameters,
 };
-use crate::sign::{EntropySource, OutputSpender, SignerProvider};
+use crate::sign::{EntropySource, NodeSigner, OutputSpender, SignerProvider};
 use crate::types::features::{ChannelFeatures, ChannelTypeFeatures, NodeFeatures};
 use crate::types::payment::{PaymentHash, PaymentSecret};
 use crate::util::config::{
@@ -5112,7 +5112,11 @@ pub fn test_key_derivation_params() {
 	let scorer = RwLock::new(test_utils::TestScorer::new());
 	let router =
 		test_utils::TestRouter::new(network_graph.clone(), &chanmon_cfgs[0].logger, &scorer);
-	let message_router = test_utils::TestMessageRouter::new(network_graph.clone(), &keys_manager);
+	let message_router = test_utils::TestMessageRouter::new(
+		network_graph.clone(),
+		&keys_manager,
+		keys_manager.get_expanded_key(),
+	);
 	let node = NodeCfg {
 		chain_source: &chanmon_cfgs[0].chain_source,
 		logger: &chanmon_cfgs[0].logger,
diff --git a/lightning/src/ln/inbound_payment.rs b/lightning/src/ln/inbound_payment.rs
index 53b212428ca..6a0b52d40b5 100644
--- a/lightning/src/ln/inbound_payment.rs
+++ b/lightning/src/ln/inbound_payment.rs
@@ -37,9 +37,9 @@ const AMT_MSAT_LEN: usize = 8;
 // retrieve said payment type bits.
 const METHOD_TYPE_OFFSET: usize = 5;
 
-/// A set of keys that were HKDF-expanded. Returned by [`NodeSigner::get_inbound_payment_key`].
+/// A set of keys that were HKDF-expanded. Returned by [`NodeSigner::get_expanded_key`].
 ///
-/// [`NodeSigner::get_inbound_payment_key`]: crate::sign::NodeSigner::get_inbound_payment_key
+/// [`NodeSigner::get_expanded_key`]: crate::sign::NodeSigner::get_expanded_key
 #[derive(Hash, Copy, Clone, PartialEq, Eq, Debug)]
 pub struct ExpandedKey {
 	/// The key used to encrypt the bytes containing the payment metadata (i.e. the amount and
@@ -133,7 +133,7 @@ fn min_final_cltv_expiry_delta_from_metadata(bytes: [u8; METADATA_LEN]) -> u16 {
 /// `ChannelManager` is required. Useful for generating invoices for [phantom node payments] without
 /// a `ChannelManager`.
 ///
-/// `keys` is generated by calling [`NodeSigner::get_inbound_payment_key`]. It is recommended to
+/// `keys` is generated by calling [`NodeSigner::get_expanded_key`]. It is recommended to
 /// cache this value and not regenerate it for each new inbound payment.
 ///
 /// `current_time` is a Unix timestamp representing the current time.
@@ -142,7 +142,7 @@ fn min_final_cltv_expiry_delta_from_metadata(bytes: [u8; METADATA_LEN]) -> u16 {
 /// on versions of LDK prior to 0.0.114.
 ///
 /// [phantom node payments]: crate::sign::PhantomKeysManager
-/// [`NodeSigner::get_inbound_payment_key`]: crate::sign::NodeSigner::get_inbound_payment_key
+/// [`NodeSigner::get_expanded_key`]: crate::sign::NodeSigner::get_expanded_key
 pub fn create<ES: Deref>(
 	keys: &ExpandedKey, min_value_msat: Option<u64>, invoice_expiry_delta_secs: u32,
 	entropy_source: &ES, current_time: u64, min_final_cltv_expiry_delta: Option<u16>,
@@ -322,7 +322,7 @@ fn construct_payment_secret(
 /// For payments including a custom `min_final_cltv_expiry_delta`, the metadata is constructed as:
 ///   payment method (3 bits) || payment amount (8 bytes - 3 bits) || min_final_cltv_expiry_delta (2 bytes) || expiry (6 bytes)
 ///
-/// In both cases the result is then encrypted using a key derived from [`NodeSigner::get_inbound_payment_key`].
+/// In both cases the result is then encrypted using a key derived from [`NodeSigner::get_expanded_key`].
 ///
 /// Then on payment receipt, we verify in this method that the payment preimage and payment secret
 /// match what was constructed.
@@ -343,7 +343,7 @@ fn construct_payment_secret(
 ///
 /// See [`ExpandedKey`] docs for more info on the individual keys used.
 ///
-/// [`NodeSigner::get_inbound_payment_key`]: crate::sign::NodeSigner::get_inbound_payment_key
+/// [`NodeSigner::get_expanded_key`]: crate::sign::NodeSigner::get_expanded_key
 /// [`create_inbound_payment`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment
 /// [`create_inbound_payment_for_hash`]: crate::ln::channelmanager::ChannelManager::create_inbound_payment_for_hash
 pub(super) fn verify<L: Deref>(
diff --git a/lightning/src/ln/invoice_utils.rs b/lightning/src/ln/invoice_utils.rs
index f2e8284a617..876f5eccb27 100644
--- a/lightning/src/ln/invoice_utils.rs
+++ b/lightning/src/ln/invoice_utils.rs
@@ -195,7 +195,7 @@ where
 		},
 	};
 
-	let keys = node_signer.get_inbound_payment_key();
+	let keys = node_signer.get_expanded_key();
 	let (payment_hash, payment_secret) = if let Some(payment_hash) = payment_hash {
 		let payment_secret = create_from_hash(
 			&keys,
diff --git a/lightning/src/ln/max_payment_path_len_tests.rs b/lightning/src/ln/max_payment_path_len_tests.rs
index 95a1fbaaa10..8fce1f20e3b 100644
--- a/lightning/src/ln/max_payment_path_len_tests.rs
+++ b/lightning/src/ln/max_payment_path_len_tests.rs
@@ -173,7 +173,7 @@ fn one_hop_blinded_path_with_custom_tlv() {
 		payment_context: PaymentContext::Bolt12Refund(Bolt12RefundContext {}),
 	};
 	let nonce = Nonce([42u8; 16]);
-	let expanded_key = chanmon_cfgs[2].keys_manager.get_inbound_payment_key();
+	let expanded_key = chanmon_cfgs[2].keys_manager.get_expanded_key();
 	let payee_tlvs = payee_tlvs.authenticate(nonce, &expanded_key);
 	let mut secp_ctx = Secp256k1::new();
 	let blinded_path = BlindedPaymentPath::new(
diff --git a/lightning/src/ln/msgs.rs b/lightning/src/ln/msgs.rs
index 2e9c3b90957..1c19c3a15d5 100644
--- a/lightning/src/ln/msgs.rs
+++ b/lightning/src/ln/msgs.rs
@@ -3443,8 +3443,8 @@ where
 				},
 				ChaChaPolyReadAdapter { readable: BlindedPaymentTlvs::Receive(receive_tlvs) } => {
 					let ReceiveTlvs { tlvs, authentication: (hmac, nonce) } = receive_tlvs;
-					let expanded_key = node_signer.get_inbound_payment_key();
-					if tlvs.verify_for_offer_payment(hmac, nonce, &expanded_key).is_err() {
+					let expanded_key = node_signer.get_expanded_key();
+					if tlvs.verify_data(hmac, nonce, &expanded_key).is_err() {
 						return Err(DecodeError::InvalidValue);
 					}
 
@@ -3595,8 +3595,8 @@ where
 					readable: BlindedTrampolineTlvs::Receive(receive_tlvs),
 				} => {
 					let ReceiveTlvs { tlvs, authentication: (hmac, nonce) } = receive_tlvs;
-					let expanded_key = node_signer.get_inbound_payment_key();
-					if tlvs.verify_for_offer_payment(hmac, nonce, &expanded_key).is_err() {
+					let expanded_key = node_signer.get_expanded_key();
+					if tlvs.verify_data(hmac, nonce, &expanded_key).is_err() {
 						return Err(DecodeError::InvalidValue);
 					}
 
diff --git a/lightning/src/ln/offers_tests.rs b/lightning/src/ln/offers_tests.rs
index f8649111a0c..bc9abd59914 100644
--- a/lightning/src/ln/offers_tests.rs
+++ b/lightning/src/ln/offers_tests.rs
@@ -2223,7 +2223,7 @@ fn fails_paying_invoice_with_unknown_required_features() {
 	let payment_paths = invoice.payment_paths().to_vec();
 	let payment_hash = invoice.payment_hash();
 
-	let expanded_key = alice.keys_manager.get_inbound_payment_key();
+	let expanded_key = alice.keys_manager.get_expanded_key();
 	let secp_ctx = Secp256k1::new();
 
 	let created_at = alice.node.duration_since_epoch();
diff --git a/lightning/src/offers/signer.rs b/lightning/src/offers/signer.rs
index 329b90d2076..82b5b6a3f78 100644
--- a/lightning/src/offers/signer.rs
+++ b/lightning/src/offers/signer.rs
@@ -9,6 +9,7 @@
 
 //! Utilities for signing offer messages and verifying metadata.
 
+use crate::blinded_path::message::UnauthenticatedDummyTlv;
 use crate::blinded_path::payment::UnauthenticatedReceiveTlvs;
 use crate::ln::channelmanager::PaymentId;
 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN};
@@ -570,3 +571,26 @@ pub(crate) fn verify_held_htlc_available_context(
 		Err(())
 	}
 }
+
+pub(crate) fn hmac_for_dummy_tlv(
+	tlvs: &UnauthenticatedDummyTlv, nonce: Nonce, expanded_key: &ExpandedKey,
+) -> Hmac<Sha256> {
+	const IV_BYTES: &[u8; IV_LEN] = b"LDK Msgs Dummies";
+	let mut hmac = expanded_key.hmac_for_offer();
+	hmac.input(IV_BYTES);
+	hmac.input(&nonce.0);
+	hmac.input(PAYMENT_TLVS_HMAC_INPUT);
+	tlvs.write(&mut hmac).unwrap();
+
+	Hmac::from_engine(hmac)
+}
+
+pub(crate) fn verify_dummy_tlv(
+	tlvs: &UnauthenticatedDummyTlv, hmac: Hmac<Sha256>, nonce: Nonce, expanded_key: &ExpandedKey,
+) -> Result<(), ()> {
+	if hmac_for_dummy_tlv(tlvs, nonce, expanded_key) == hmac {
+		Ok(())
+	} else {
+		Err(())
+	}
+}
diff --git a/lightning/src/onion_message/functional_tests.rs b/lightning/src/onion_message/functional_tests.rs
index b28819ee692..a7dd0d6f6f5 100644
--- a/lightning/src/onion_message/functional_tests.rs
+++ b/lightning/src/onion_message/functional_tests.rs
@@ -26,6 +26,7 @@ use crate::blinded_path::message::{
 use crate::blinded_path::utils::is_padded;
 use crate::blinded_path::EmptyNodeIdLookUp;
 use crate::events::{Event, EventsProvider};
+use crate::ln::inbound_payment::ExpandedKey;
 use crate::ln::msgs::{self, BaseMessageHandler, DecodeError, OnionMessageHandler};
 use crate::routing::gossip::{NetworkGraph, P2PGossipSync};
 use crate::routing::test_utils::{add_channel, add_or_update_node};
@@ -279,8 +280,11 @@ fn create_nodes_using_cfgs(cfgs: Vec<MessengerCfg>) -> Vec<MessengerNode> {
 		let node_signer = Arc::new(TestNodeSigner::new(secret_key));
 
 		let node_id_lookup = Arc::new(EmptyNodeIdLookUp {});
-		let message_router =
-			Arc::new(DefaultMessageRouter::new(network_graph.clone(), entropy_source.clone()));
+		let message_router = Arc::new(DefaultMessageRouter::new(
+			network_graph.clone(),
+			entropy_source.clone(),
+			node_signer.get_expanded_key(),
+		));
 		let offers_message_handler = Arc::new(TestOffersMessageHandler {});
 		let async_payments_message_handler = Arc::new(TestAsyncPaymentsMessageHandler {});
 		let dns_resolver_message_handler = Arc::new(TestDNSResolverMessageHandler {});
@@ -418,6 +422,34 @@ fn one_blinded_hop() {
 	pass_along_path(&nodes);
 }
 
+#[test]
+fn blinded_path_with_dummy() {
+	let nodes = create_nodes(2);
+	let test_msg = TestCustomMessage::Pong;
+
+	let secp_ctx = Secp256k1::new();
+	let context = MessageContext::Custom(Vec::new());
+	let entropy = &*nodes[1].entropy_source;
+	let expanded_key = ExpandedKey::new([42; 32]);
+	let blinded_path = BlindedMessagePath::new_with_dummy_hops(
+		&[],
+		5,
+		nodes[1].node_id,
+		context,
+		entropy,
+		&expanded_key,
+		&secp_ctx,
+	)
+	.unwrap();
+	// Ensure that dummy hops are added to the blinded path.
+	assert_eq!(blinded_path.blinded_hops().len(), 6);
+	let destination = Destination::BlindedPath(blinded_path);
+	let instructions = MessageSendInstructions::WithoutReplyPath { destination };
+	nodes[0].messenger.send_onion_message(test_msg, instructions).unwrap();
+	nodes[1].custom_message_handler.expect_message(TestCustomMessage::Pong);
+	pass_along_path(&nodes);
+}
+
 #[test]
 fn two_unblinded_two_blinded() {
 	let nodes = create_nodes(5);
@@ -611,11 +643,14 @@ fn test_blinded_path_padding_for_full_length_path() {
 	// Update the context to create a larger final receive TLVs, ensuring that
 	// the hop sizes vary before padding.
 	let context = MessageContext::Custom(vec![0u8; 42]);
-	let blinded_path = BlindedMessagePath::new(
+	let expanded_key = ExpandedKey::new([42; 32]);
+	let blinded_path = BlindedMessagePath::new_with_dummy_hops(
 		&intermediate_nodes,
+		5,
 		nodes[3].node_id,
 		context,
 		&*nodes[3].entropy_source,
+		&expanded_key,
 		&secp_ctx,
 	)
 	.unwrap();
@@ -644,15 +679,19 @@ fn test_blinded_path_no_padding_for_compact_path() {
 	// Update the context to create a larger final receive TLVs, ensuring that
 	// the hop sizes vary before padding.
 	let context = MessageContext::Custom(vec![0u8; 42]);
-	let blinded_path = BlindedMessagePath::new(
+	let expanded_key = ExpandedKey::new([42; 32]);
+	let blinded_path = BlindedMessagePath::new_with_dummy_hops(
 		&intermediate_nodes,
+		5,
 		nodes[3].node_id,
 		context,
 		&*nodes[3].entropy_source,
+		&expanded_key,
 		&secp_ctx,
 	)
 	.unwrap();
 
+	// Ensure that the hops are not padded.
 	assert!(!is_padded(&blinded_path.blinded_hops(), MESSAGE_PADDING_ROUND_OFF));
 }
 
diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index 6009a276976..c99e54e941c 100644
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -13,6 +13,7 @@
 use bitcoin::hashes::hmac::{Hmac, HmacEngine};
 use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::secp256k1::ecdh::SharedSecret;
 use bitcoin::secp256k1::{self, PublicKey, Scalar, Secp256k1, SecretKey};
 
 #[cfg(async_payments)]
@@ -20,8 +21,8 @@ use super::async_payments::AsyncPaymentsMessage;
 use super::async_payments::AsyncPaymentsMessageHandler;
 use super::dns_resolution::{DNSResolverMessage, DNSResolverMessageHandler};
 use super::offers::{OffersMessage, OffersMessageHandler};
-use super::packet::OnionMessageContents;
 use super::packet::ParsedOnionMessageContents;
+use super::packet::{DummyControlTlvs, OnionMessageContents};
 use super::packet::{
 	ForwardControlTlvs, Packet, Payload, ReceiveControlTlvs, BIG_PACKET_HOP_DATA_LEN,
 	SMALL_PACKET_HOP_DATA_LEN,
@@ -29,16 +30,17 @@ use super::packet::{
 #[cfg(async_payments)]
 use crate::blinded_path::message::AsyncPaymentsContext;
 use crate::blinded_path::message::{
-	BlindedMessagePath, DNSResolverContext, ForwardTlvs, MessageContext, MessageForwardNode,
-	NextMessageHop, OffersContext, ReceiveTlvs,
+	BlindedMessagePath, DNSResolverContext, DummyTlv, ForwardTlvs, MessageContext,
+	MessageForwardNode, NextMessageHop, OffersContext, PrimaryDummyTlv, ReceiveTlvs,
 };
 use crate::blinded_path::utils;
 use crate::blinded_path::{IntroductionNode, NodeIdLookUp};
 use crate::events::{Event, EventHandler, EventsProvider, ReplayEvent};
+use crate::ln::channelmanager::Verification;
 use crate::ln::msgs::{
 	self, BaseMessageHandler, MessageSendEvent, OnionMessage, OnionMessageHandler, SocketAddress,
 };
-use crate::ln::onion_utils;
+use crate::ln::{inbound_payment, onion_utils};
 use crate::routing::gossip::{NetworkGraph, NodeId, ReadOnlyNetworkGraph};
 use crate::sign::{EntropySource, NodeSigner, Recipient};
 use crate::types::features::{InitFeatures, NodeFeatures};
@@ -539,6 +541,7 @@ where
 {
 	network_graph: G,
 	entropy_source: ES,
+	expanded_key: inbound_payment::ExpandedKey,
 }
 
 impl<G: Deref<Target = NetworkGraph<L>>, L: Deref, ES: Deref> DefaultMessageRouter<G, L, ES>
@@ -547,8 +550,10 @@ where
 	ES::Target: EntropySource,
 {
 	/// Creates a [`DefaultMessageRouter`] using the given [`NetworkGraph`].
-	pub fn new(network_graph: G, entropy_source: ES) -> Self {
-		Self { network_graph, entropy_source }
+	pub fn new(
+		network_graph: G, entropy_source: ES, expanded_key: inbound_payment::ExpandedKey,
+	) -> Self {
+		Self { network_graph, entropy_source, expanded_key }
 	}
 
 	fn create_blinded_paths_from_iter<
@@ -556,7 +561,8 @@ where
 		T: secp256k1::Signing + secp256k1::Verification,
 	>(
 		network_graph: &G, recipient: PublicKey, context: MessageContext, peers: I,
-		entropy_source: &ES, secp_ctx: &Secp256k1<T>, compact_paths: bool,
+		entropy_source: &ES, expanded_key: &inbound_payment::ExpandedKey, secp_ctx: &Secp256k1<T>,
+		compact_paths: bool,
 	) -> Result<Vec<BlindedMessagePath>, ()> {
 		// Limit the number of blinded paths that are computed.
 		const MAX_PATHS: usize = 3;
@@ -565,6 +571,19 @@ where
 		// recipient's node_id.
 		const MIN_PEER_CHANNELS: usize = 3;
 
+		// Add a random number (0 to 5) of dummy hops to each non-compact blinded path
+		// to make it harder to infer the recipient's position.
+		//
+		// # Note on compact paths:
+		//
+		// Compact paths are optimized for minimal size. Adding dummy hops to them
+		// would increase their size and negate their primary advantage.
+		// Therefore, we avoid adding dummy hops to compact paths.
+		let dummy_hops_count = compact_paths.then_some(0).unwrap_or_else(|| {
+			let random_byte = entropy_source.get_secure_random_bytes()[0];
+			random_byte % 6
+		});
+
 		let network_graph = network_graph.deref().read_only();
 		let is_recipient_announced =
 			network_graph.nodes().contains_key(&NodeId::from_pubkey(&recipient));
@@ -595,7 +614,15 @@ where
 		let paths = peer_info
 			.into_iter()
 			.map(|(peer, _, _)| {
-				BlindedMessagePath::new(&[peer], recipient, context.clone(), entropy, secp_ctx)
+				BlindedMessagePath::new_with_dummy_hops(
+					&[peer],
+					dummy_hops_count,
+					recipient,
+					context.clone(),
+					entropy,
+					expanded_key,
+					secp_ctx,
+				)
 			})
 			.take(MAX_PATHS)
 			.collect::<Result<Vec<_>, _>>();
@@ -664,7 +691,7 @@ where
 
 	pub(crate) fn create_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
 		network_graph: &G, recipient: PublicKey, context: MessageContext, peers: Vec<PublicKey>,
-		entropy_source: &ES, secp_ctx: &Secp256k1<T>,
+		entropy_source: &ES, expanded_key: &inbound_payment::ExpandedKey, secp_ctx: &Secp256k1<T>,
 	) -> Result<Vec<BlindedMessagePath>, ()> {
 		let peers =
 			peers.into_iter().map(|node_id| MessageForwardNode { node_id, short_channel_id: None });
@@ -674,6 +701,7 @@ where
 			context,
 			peers.into_iter(),
 			entropy_source,
+			expanded_key,
 			secp_ctx,
 			false,
 		)
@@ -681,7 +709,8 @@ where
 
 	pub(crate) fn create_compact_blinded_paths<T: secp256k1::Signing + secp256k1::Verification>(
 		network_graph: &G, recipient: PublicKey, context: MessageContext,
-		peers: Vec<MessageForwardNode>, entropy_source: &ES, secp_ctx: &Secp256k1<T>,
+		peers: Vec<MessageForwardNode>, entropy_source: &ES,
+		expanded_key: &inbound_payment::ExpandedKey, secp_ctx: &Secp256k1<T>,
 	) -> Result<Vec<BlindedMessagePath>, ()> {
 		Self::create_blinded_paths_from_iter(
 			network_graph,
@@ -689,6 +718,7 @@ where
 			context,
 			peers.into_iter(),
 			entropy_source,
+			expanded_key,
 			secp_ctx,
 			true,
 		)
@@ -717,6 +747,7 @@ where
 			context,
 			peers,
 			&self.entropy_source,
+			&self.expanded_key,
 			secp_ctx,
 		)
 	}
@@ -731,6 +762,7 @@ where
 			context,
 			peers,
 			&self.entropy_source,
+			&self.expanded_key,
 			secp_ctx,
 		)
 	}
@@ -1045,44 +1077,46 @@ where
 	L::Target: Logger,
 	CMH::Target: CustomOnionMessageHandler,
 {
-	let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, &msg.blinding_point, None) {
-		Ok(ss) => ss,
-		Err(e) => {
-			log_error!(logger, "Failed to retrieve node secret: {:?}", e);
-			return Err(());
-		},
-	};
-	let onion_decode_ss = {
-		let blinding_factor = {
-			let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
-			hmac.input(control_tlvs_ss.as_ref());
-			let hmac = Hmac::from_engine(hmac).to_byte_array();
-			Scalar::from_be_bytes(hmac).unwrap()
-		};
-		let packet_pubkey = &msg.onion_routing_packet.public_key;
-		match node_signer.ecdh(Recipient::Node, packet_pubkey, Some(&blinding_factor)) {
-			Ok(ss) => ss.secret_bytes(),
-			Err(()) => {
-				log_trace!(logger, "Failed to compute onion packet shared secret");
+	// Helper function to compute shared secrets for onion decoding
+	let compute_shared_secrets = |blinding_point: &PublicKey,
+	                              packet_pubkey: &PublicKey|
+	 -> Result<(SharedSecret, [u8; 32]), ()> {
+		let control_tlvs_ss = match node_signer.ecdh(Recipient::Node, blinding_point, None) {
+			Ok(ss) => ss,
+			Err(e) => {
+				log_error!(logger, "Failed to retrieve node secret: {:?}", e);
 				return Err(());
 			},
-		}
+		};
+
+		let onion_decode_ss = {
+			let blinding_factor = {
+				let mut hmac = HmacEngine::<Sha256>::new(b"blinded_node_id");
+				hmac.input(control_tlvs_ss.as_ref());
+				let hmac = Hmac::from_engine(hmac).to_byte_array();
+				Scalar::from_be_bytes(hmac).unwrap()
+			};
+			match node_signer.ecdh(Recipient::Node, packet_pubkey, Some(&blinding_factor)) {
+				Ok(ss) => ss.secret_bytes(),
+				Err(()) => {
+					log_trace!(logger, "Failed to compute onion packet shared secret");
+					return Err(());
+				},
+			}
+		};
+
+		Ok((control_tlvs_ss, onion_decode_ss))
 	};
-	let next_hop = onion_utils::decode_next_untagged_hop(
-		onion_decode_ss,
-		&msg.onion_routing_packet.hop_data[..],
-		msg.onion_routing_packet.hmac,
-		(control_tlvs_ss, custom_handler.deref(), logger.deref()),
-	);
-	match next_hop {
-		Ok((
-			Payload::Receive {
-				message,
-				control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { context }),
-				reply_path,
-			},
-			None,
-		)) => match (message, context) {
+
+	// Helper function to process receive payloads
+	let process_receive_payload = |message,
+	                               context,
+	                               reply_path|
+	 -> Result<
+		PeeledOnion<<<CMH>::Target as CustomOnionMessageHandler>::CustomMessage>,
+		(),
+	> {
+		match (message, context) {
 			(ParsedOnionMessageContents::Offers(msg), Some(MessageContext::Offers(ctx))) => {
 				Ok(PeeledOnion::Offers(msg, Some(ctx), reply_path))
 			},
@@ -1114,55 +1148,201 @@ where
 				);
 				Err(())
 			},
-		},
-		Ok((
-			Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
-				next_hop,
-				next_blinding_override,
-			})),
-			Some((next_hop_hmac, new_packet_bytes)),
-		)) => {
-			// TODO: we need to check whether `next_hop` is our node, in which case this is a dummy
-			// blinded hop and this onion message is destined for us. In this situation, we should keep
-			// unwrapping the onion layers to get to the final payload. Since we don't have the option
-			// of creating blinded paths with dummy hops currently, we should be ok to not handle this
-			// for now.
-			let packet_pubkey = msg.onion_routing_packet.public_key;
-			let new_pubkey_opt =
-				onion_utils::next_hop_pubkey(&secp_ctx, packet_pubkey, &onion_decode_ss);
-			let new_pubkey = match new_pubkey_opt {
-				Ok(pk) => pk,
+		}
+	};
+
+	// Constructs the next onion message using packet data and blinding logic.
+	let compute_onion_message = |packet_pubkey: PublicKey,
+	                             next_hop_hmac: [u8; 32],
+	                             new_packet_bytes: Vec<u8>,
+	                             current_blinding_point: PublicKey,
+	                             current_control_tlvs_ss: SharedSecret,
+	                             current_onion_decode_ss: [u8; 32],
+	                             blinding_point_opt: Option<PublicKey>|
+	 -> Result<OnionMessage, ()> {
+		let new_pubkey = match onion_utils::next_hop_pubkey(
+			&secp_ctx,
+			packet_pubkey,
+			&current_onion_decode_ss,
+		) {
+			Ok(pk) => pk,
+			Err(e) => {
+				log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
+				return Err(());
+			},
+		};
+		let outgoing_packet = Packet {
+			version: 0,
+			public_key: new_pubkey,
+			hop_data: new_packet_bytes,
+			hmac: next_hop_hmac,
+		};
+		let blinding_point = match blinding_point_opt {
+			Some(bp) => bp,
+			None => match onion_utils::next_hop_pubkey(
+				&secp_ctx,
+				current_blinding_point,
+				current_control_tlvs_ss.as_ref(),
+			) {
+				Ok(bp) => bp,
 				Err(e) => {
-					log_trace!(logger, "Failed to compute next hop packet pubkey: {}", e);
+					log_trace!(logger, "Failed to compute next blinding point: {}", e);
 					return Err(());
 				},
-			};
-			let outgoing_packet = Packet {
-				version: 0,
-				public_key: new_pubkey,
-				hop_data: new_packet_bytes,
-				hmac: next_hop_hmac,
-			};
-			let onion_message = OnionMessage {
-				blinding_point: match next_blinding_override {
-					Some(blinding_point) => blinding_point,
-					None => {
-						match onion_utils::next_hop_pubkey(
+			},
+		};
+		Ok(OnionMessage { blinding_point, onion_routing_packet: outgoing_packet })
+	};
+
+	let (control_tlvs_ss, onion_decode_ss) =
+		compute_shared_secrets(&msg.blinding_point, &msg.onion_routing_packet.public_key)?;
+
+	let next_hop = onion_utils::decode_next_untagged_hop(
+		onion_decode_ss,
+		&msg.onion_routing_packet.hop_data[..],
+		msg.onion_routing_packet.hmac,
+		(control_tlvs_ss, custom_handler.deref(), logger.deref()),
+	);
+
+	match next_hop {
+		Ok((
+			Payload::Receive {
+				message,
+				control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { context }),
+				reply_path,
+			},
+			None,
+		)) => process_receive_payload(message, context, reply_path),
+		Ok((
+			Payload::Dummy(DummyControlTlvs::Unblinded(DummyTlv::Primary(PrimaryDummyTlv {
+				dummy_tlv,
+				authentication,
+			}))),
+			Some((next_hop_hmac, new_packet_bytes)),
+		)) => {
+			let expanded_key = node_signer.get_expanded_key();
+			dummy_tlv.verify_data(authentication.0, authentication.1, &expanded_key)?;
+
+			// Start iterative processing of the dummy chain
+			let mut current_message = compute_onion_message(
+				msg.onion_routing_packet.public_key,
+				next_hop_hmac,
+				new_packet_bytes,
+				msg.blinding_point,
+				control_tlvs_ss,
+				onion_decode_ss,
+				None,
+			)?;
+
+			// Process subsequent dummy hops iteratively
+			loop {
+				let (current_control_tlvs_ss, current_onion_decode_ss) = compute_shared_secrets(
+					&current_message.blinding_point,
+					&current_message.onion_routing_packet.public_key,
+				)?;
+
+				let current_next_hop = onion_utils::decode_next_untagged_hop(
+					current_onion_decode_ss,
+					&current_message.onion_routing_packet.hop_data[..],
+					current_message.onion_routing_packet.hmac,
+					(current_control_tlvs_ss, custom_handler.deref(), logger.deref()),
+				);
+
+				match current_next_hop {
+					Ok((
+						Payload::Dummy(DummyControlTlvs::Unblinded(DummyTlv::Subsequent)),
+						Some((next_hop_hmac, new_packet_bytes)),
+					)) => {
+						// Valid: Subsequent dummy after Primary dummy, continue processing
+						let new_pubkey = match onion_utils::next_hop_pubkey(
+							&secp_ctx,
+							current_message.onion_routing_packet.public_key,
+							&current_onion_decode_ss,
+						) {
+							Ok(pk) => pk,
+							Err(e) => {
+								log_trace!(
+									logger,
+									"Failed to compute next hop packet pubkey: {}",
+									e
+								);
+								return Err(());
+							},
+						};
+						let outgoing_packet = Packet {
+							version: 0,
+							public_key: new_pubkey,
+							hop_data: new_packet_bytes,
+							hmac: next_hop_hmac,
+						};
+						let blinding_point = match onion_utils::next_hop_pubkey(
 							&secp_ctx,
-							msg.blinding_point,
-							control_tlvs_ss.as_ref(),
+							current_message.blinding_point,
+							current_control_tlvs_ss.as_ref(),
 						) {
 							Ok(bp) => bp,
 							Err(e) => {
 								log_trace!(logger, "Failed to compute next blinding point: {}", e);
 								return Err(());
 							},
-						}
+						};
+						current_message =
+							OnionMessage { blinding_point, onion_routing_packet: outgoing_packet };
 					},
-				},
-				onion_routing_packet: outgoing_packet,
-			};
-
+					Ok((
+						Payload::Receive {
+							message,
+							control_tlvs: ReceiveControlTlvs::Unblinded(ReceiveTlvs { context }),
+							reply_path,
+						},
+						None,
+					)) => {
+						// End of dummy chain, process the final receive payload
+						return process_receive_payload(message, context, reply_path);
+					},
+					Err(e) => {
+						log_trace!(
+							logger,
+							"Errored decoding onion message packet in dummy chain: {:?}",
+							e
+						);
+						return Err(());
+					},
+					_ => {
+						// Invalid: anything else breaks the expected structure
+						log_trace!(
+							logger,
+							"Invalid payload type in dummy chain. Expected Subsequent dummy or Receive payload."
+						);
+						return Err(());
+					},
+				}
+			}
+		},
+		Ok((Payload::Dummy(DummyControlTlvs::Unblinded(DummyTlv::Subsequent)), _)) => {
+			// ERROR: Subsequent dummy without preceding Primary dummy
+			log_trace!(
+				logger,
+				"Received Subsequent dummy without preceding Primary dummy - invalid structure"
+			);
+			Err(())
+		},
+		Ok((
+			Payload::Forward(ForwardControlTlvs::Unblinded(ForwardTlvs {
+				next_hop,
+				next_blinding_override,
+			})),
+			Some((next_hop_hmac, new_packet_bytes)),
+		)) => {
+			let onion_message = compute_onion_message(
+				msg.onion_routing_packet.public_key,
+				next_hop_hmac,
+				new_packet_bytes,
+				msg.blinding_point,
+				control_tlvs_ss,
+				onion_decode_ss,
+				next_blinding_override,
+			)?;
 			Ok(PeeledOnion::Forward(next_hop, onion_message))
 		},
 		Err(e) => {
diff --git a/lightning/src/onion_message/packet.rs b/lightning/src/onion_message/packet.rs
index 632cbc9c8a3..d3e6e204113 100644
--- a/lightning/src/onion_message/packet.rs
+++ b/lightning/src/onion_message/packet.rs
@@ -17,7 +17,10 @@ use super::async_payments::AsyncPaymentsMessage;
 use super::dns_resolution::DNSResolverMessage;
 use super::messenger::CustomOnionMessageHandler;
 use super::offers::OffersMessage;
-use crate::blinded_path::message::{BlindedMessagePath, ForwardTlvs, NextMessageHop, ReceiveTlvs};
+use crate::blinded_path::message::{
+	BlindedMessagePath, DummyTlv, ForwardTlvs, NextMessageHop, PrimaryDummyTlv, ReceiveTlvs,
+	UnauthenticatedDummyTlv,
+};
 use crate::crypto::streams::{ChaChaPolyReadAdapter, ChaChaPolyWriteAdapter};
 use crate::ln::msgs::DecodeError;
 use crate::ln::onion_utils;
@@ -111,6 +114,8 @@ impl LengthReadable for Packet {
 pub(super) enum Payload<T: OnionMessageContents> {
 	/// This payload is for an intermediate hop.
 	Forward(ForwardControlTlvs),
+	/// This payload is dummy, and is inteded to be peeled.
+	Dummy(DummyControlTlvs),
 	/// This payload is for the final hop.
 	Receive { control_tlvs: ReceiveControlTlvs, reply_path: Option<BlindedMessagePath>, message: T },
 }
@@ -204,6 +209,11 @@ pub(super) enum ForwardControlTlvs {
 	Unblinded(ForwardTlvs),
 }
 
+pub(super) enum DummyControlTlvs {
+	/// See [`ForwardControlTlvs::Unblinded`]
+	Unblinded(DummyTlv),
+}
+
 /// Receive control TLVs in their blinded and unblinded form.
 pub(super) enum ReceiveControlTlvs {
 	/// See [`ForwardControlTlvs::Blinded`].
@@ -234,6 +244,10 @@ impl<T: OnionMessageContents> Writeable for (Payload<T>, [u8; 32]) {
 				let write_adapter = ChaChaPolyWriteAdapter::new(self.1, &control_tlvs);
 				_encode_varint_length_prefixed_tlv!(w, { (4, write_adapter, required) })
 			},
+			Payload::Dummy(DummyControlTlvs::Unblinded(control_tlvs)) => {
+				let write_adapter = ChaChaPolyWriteAdapter::new(self.1, &control_tlvs);
+				_encode_varint_length_prefixed_tlv!(w, { (4, write_adapter, required) })
+			},
 			Payload::Receive {
 				control_tlvs: ReceiveControlTlvs::Unblinded(control_tlvs),
 				reply_path,
@@ -310,6 +324,9 @@ impl<H: CustomOnionMessageHandler + ?Sized, L: Logger + ?Sized> ReadableArgs<(Sh
 				}
 				Ok(Payload::Forward(ForwardControlTlvs::Unblinded(tlvs)))
 			},
+			Some(ChaChaPolyReadAdapter { readable: ControlTlvs::Dummy(tlvs) }) => {
+				Ok(Payload::Dummy(DummyControlTlvs::Unblinded(tlvs)))
+			},
 			Some(ChaChaPolyReadAdapter { readable: ControlTlvs::Receive(tlvs) }) => {
 				Ok(Payload::Receive {
 					control_tlvs: ReceiveControlTlvs::Unblinded(tlvs),
@@ -328,6 +345,8 @@ impl<H: CustomOnionMessageHandler + ?Sized, L: Logger + ?Sized> ReadableArgs<(Sh
 pub(crate) enum ControlTlvs {
 	/// This onion message is intended to be forwarded.
 	Forward(ForwardTlvs),
+	/// This onion message is a dummy, and is intended to be peeled.
+	Dummy(DummyTlv),
 	/// This onion message is intended to be received.
 	Receive(ReceiveTlvs),
 }
@@ -343,6 +362,8 @@ impl Readable for ControlTlvs {
 			(4, next_node_id, option),
 			(8, next_blinding_override, option),
 			(65537, context, option),
+			(65539, authentication, option),
+			(65541, dummy_tlv, option),
 		});
 
 		let next_hop = match (short_channel_id, next_node_id) {
@@ -352,18 +373,18 @@ impl Readable for ControlTlvs {
 			(None, None) => None,
 		};
 
-		let valid_fwd_fmt = next_hop.is_some();
-		let valid_recv_fmt = next_hop.is_none() && next_blinding_override.is_none();
-
-		let payload_fmt = if valid_fwd_fmt {
-			ControlTlvs::Forward(ForwardTlvs {
-				next_hop: next_hop.unwrap(),
-				next_blinding_override,
-			})
-		} else if valid_recv_fmt {
-			ControlTlvs::Receive(ReceiveTlvs { context })
-		} else {
-			return Err(DecodeError::InvalidValue);
+		let payload_fmt = match (dummy_tlv, next_hop, next_blinding_override, authentication) {
+			(None, Some(hop), _, None) => {
+				ControlTlvs::Forward(ForwardTlvs { next_hop: hop, next_blinding_override })
+			},
+			(None, None, None, None) => ControlTlvs::Receive(ReceiveTlvs { context }),
+			(Some(()), None, None, Some(auth)) => {
+				let tlv =
+					PrimaryDummyTlv { dummy_tlv: UnauthenticatedDummyTlv {}, authentication: auth };
+				ControlTlvs::Dummy(DummyTlv::Primary(tlv))
+			},
+			(Some(()), None, None, None) => ControlTlvs::Dummy(DummyTlv::Subsequent),
+			_ => return Err(DecodeError::InvalidValue),
 		};
 
 		Ok(payload_fmt)
@@ -374,6 +395,7 @@ impl Writeable for ControlTlvs {
 	fn write<W: Writer>(&self, w: &mut W) -> Result<(), io::Error> {
 		match self {
 			Self::Forward(tlvs) => tlvs.write(w),
+			Self::Dummy(tlvs) => tlvs.write(w),
 			Self::Receive(tlvs) => tlvs.write(w),
 		}
 	}
diff --git a/lightning/src/sign/mod.rs b/lightning/src/sign/mod.rs
index f35a407634a..57af75d1ef1 100644
--- a/lightning/src/sign/mod.rs
+++ b/lightning/src/sign/mod.rs
@@ -820,19 +820,24 @@ pub trait EntropySource {
 
 /// A trait that can handle cryptographic operations at the scope level of a node.
 pub trait NodeSigner {
-	/// Get the [`ExpandedKey`] for use in encrypting and decrypting inbound payment data.
+	/// Get the [`ExpandedKey`] which provides cryptographic material for various Lightning Network operations.
+	///
+	/// This key set is used for:
+	/// - Encrypting and decrypting inbound payment metadata
+	/// - Authenticating payment hashes (both LDK-provided and user-provided)
+	/// - Supporting BOLT 12 Offers functionality (signing and encryption)
+	/// - Authenticating spontaneous payments' metadata
 	///
 	/// 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.
+	/// This method must return the same value each time it is called, as LDK avoids storing inbound
+	/// payment data by encrypting it in the payment hash and/or payment secret. Consistency is also
+	/// required for signature and encryption verification in Offers and spontaneous payments.
 	///
 	/// [phantom node payments]: PhantomKeysManager
-	fn get_inbound_payment_key(&self) -> ExpandedKey;
+	fn get_expanded_key(&self) -> ExpandedKey;
 
 	/// Get node id based on the provided [`Recipient`].
 	///
@@ -2113,7 +2118,7 @@ impl NodeSigner for KeysManager {
 		Ok(SharedSecret::new(other_key, &node_secret))
 	}
 
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
+	fn get_expanded_key(&self) -> ExpandedKey {
 		self.inbound_payment_key.clone()
 	}
 
@@ -2274,7 +2279,7 @@ impl NodeSigner for PhantomKeysManager {
 		Ok(SharedSecret::new(other_key, &node_secret))
 	}
 
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
+	fn get_expanded_key(&self) -> ExpandedKey {
 		self.inbound_payment_key.clone()
 	}
 
diff --git a/lightning/src/util/dyn_signer.rs b/lightning/src/util/dyn_signer.rs
index 939e40cf7c4..2efedbb2355 100644
--- a/lightning/src/util/dyn_signer.rs
+++ b/lightning/src/util/dyn_signer.rs
@@ -214,7 +214,7 @@ inner,
 	fn sign_bolt12_invoice(,
 		invoice: &crate::offers::invoice::UnsignedBolt12Invoice
 	) -> Result<secp256k1::schnorr::Signature, ()>,
-	fn get_inbound_payment_key(,) -> ExpandedKey
+	fn get_expanded_key(,) -> ExpandedKey
 );
 
 delegate!(DynKeysInterface, SignerProvider,
@@ -278,7 +278,7 @@ delegate!(DynPhantomKeysInterface, NodeSigner,
 	fn sign_invoice(, invoice: &RawBolt11Invoice, recipient: Recipient) -> Result<RecoverableSignature, ()>,
 	fn sign_bolt12_invoice(, invoice: &crate::offers::invoice::UnsignedBolt12Invoice
 	) -> Result<secp256k1::schnorr::Signature, ()>,
-	fn get_inbound_payment_key(,) -> ExpandedKey
+	fn get_expanded_key(,) -> ExpandedKey
 );
 
 impl SignerProvider for DynPhantomKeysInterface {
diff --git a/lightning/src/util/test_utils.rs b/lightning/src/util/test_utils.rs
index f90bfb97ef7..c658a4ab87a 100644
--- a/lightning/src/util/test_utils.rs
+++ b/lightning/src/util/test_utils.rs
@@ -25,11 +25,11 @@ use crate::events::bump_transaction::{Utxo, WalletSource};
 #[cfg(any(test, feature = "_externalize_tests"))]
 use crate::ln::chan_utils::CommitmentTransaction;
 use crate::ln::channel_state::ChannelDetails;
-use crate::ln::channelmanager;
 use crate::ln::inbound_payment::ExpandedKey;
 use crate::ln::msgs::{BaseMessageHandler, MessageSendEvent};
 use crate::ln::script::ShutdownScript;
 use crate::ln::types::ChannelId;
+use crate::ln::{channelmanager, inbound_payment};
 use crate::ln::{msgs, wire};
 use crate::offers::invoice::UnsignedBolt12Invoice;
 use crate::onion_message::messenger::{
@@ -324,8 +324,9 @@ pub struct TestMessageRouter<'a> {
 impl<'a> TestMessageRouter<'a> {
 	pub fn new(
 		network_graph: Arc<NetworkGraph<&'a TestLogger>>, entropy_source: &'a TestKeysInterface,
+		expanded_key: inbound_payment::ExpandedKey,
 	) -> Self {
-		Self { inner: DefaultMessageRouter::new(network_graph, entropy_source) }
+		Self { inner: DefaultMessageRouter::new(network_graph, entropy_source, expanded_key) }
 	}
 }
 
@@ -1486,8 +1487,8 @@ impl TestNodeSigner {
 }
 
 impl NodeSigner for TestNodeSigner {
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
-		unreachable!()
+	fn get_expanded_key(&self) -> ExpandedKey {
+		ExpandedKey::new([42; 32])
 	}
 
 	fn get_node_id(&self, recipient: Recipient) -> Result<PublicKey, ()> {
@@ -1559,8 +1560,8 @@ impl NodeSigner for TestKeysInterface {
 		self.backing.ecdh(recipient, other_key, tweak)
 	}
 
-	fn get_inbound_payment_key(&self) -> ExpandedKey {
-		self.backing.get_inbound_payment_key()
+	fn get_expanded_key(&self) -> ExpandedKey {
+		self.backing.get_expanded_key()
 	}
 
 	fn sign_invoice(