X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Foffers%2Finvoice_request.rs;h=cdf94a2e80d5bee168deea35fdb03c817718cdc7;hb=1e580668684d4dbf11d69d75e5d4a5c4f8cc40bf;hp=792214d5250e340dfe40f54fe967678740a25b01;hpb=af318b6efb1398099fc9c42f630b74abcc0b4fba;p=rust-lightning

diff --git a/lightning/src/offers/invoice_request.rs b/lightning/src/offers/invoice_request.rs
index 792214d5..cdf94a2e 100644
--- a/lightning/src/offers/invoice_request.rs
+++ b/lightning/src/offers/invoice_request.rs
@@ -23,16 +23,16 @@
 //! extern crate bitcoin;
 //! extern crate lightning;
 //!
-//! use bitcoin::network::constants::Network;
-//! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
-//! use core::convert::Infallible;
+//! use bitcoin::network::Network;
+//! use bitcoin::secp256k1::{Keypair, PublicKey, Secp256k1, SecretKey};
 //! use lightning::ln::features::OfferFeatures;
+//! use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 //! use lightning::offers::offer::Offer;
 //! use lightning::util::ser::Writeable;
 //!
 //! # fn parse() -> Result<(), lightning::offers::parse::Bolt12ParseError> {
 //! let secp_ctx = Secp256k1::new();
-//! let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32])?);
+//! let keys = Keypair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32])?);
 //! let pubkey = PublicKey::from(keys);
 //! let mut buffer = Vec::new();
 //!
@@ -47,8 +47,8 @@
 //!     .quantity(5)?
 //!     .payer_note("foo".to_string())
 //!     .build()?
-//!     .sign::<_, Infallible>(
-//!         |message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
+//!     .sign(|message: &UnsignedInvoiceRequest|
+//!         Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
 //!     )
 //!     .expect("failed verifying signature")
 //!     .write(&mut buffer)
@@ -58,28 +58,37 @@
 //! ```
 
 use bitcoin::blockdata::constants::ChainHash;
-use bitcoin::network::constants::Network;
-use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, self};
+use bitcoin::network::Network;
+use bitcoin::secp256k1::{Keypair, PublicKey, Secp256k1, self};
 use bitcoin::secp256k1::schnorr::Signature;
-use core::convert::{AsRef, Infallible, TryFrom};
 use core::ops::Deref;
 use crate::sign::EntropySource;
 use crate::io;
 use crate::blinded_path::BlindedPath;
-use crate::ln::PaymentHash;
+use crate::ln::types::PaymentHash;
 use crate::ln::channelmanager::PaymentId;
 use crate::ln::features::InvoiceRequestFeatures;
 use crate::ln::inbound_payment::{ExpandedKey, IV_LEN, Nonce};
 use crate::ln::msgs::DecodeError;
-use crate::offers::invoice::{BlindedPayInfo, DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder};
-use crate::offers::merkle::{SignError, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, self};
-use crate::offers::offer::{Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef};
+use crate::offers::invoice::BlindedPayInfo;
+use crate::offers::merkle::{SignError, SignFn, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, self};
+use crate::offers::offer::{Offer, OfferContents, OfferId, OfferTlvStream, OfferTlvStreamRef};
 use crate::offers::parse::{Bolt12ParseError, ParsedMessage, Bolt12SemanticError};
 use crate::offers::payer::{PayerContents, PayerTlvStream, PayerTlvStreamRef};
 use crate::offers::signer::{Metadata, MetadataMaterial};
-use crate::util::ser::{HighZeroBytesDroppedBigSize, SeekReadable, WithoutLength, Writeable, Writer};
-use crate::util::string::PrintableString;
+use crate::util::ser::{HighZeroBytesDroppedBigSize, Readable, SeekReadable, WithoutLength, Writeable, Writer};
+use crate::util::string::{PrintableString, UntrustedString};
 
+#[cfg(not(c_bindings))]
+use {
+	crate::offers::invoice::{DerivedSigningPubkey, ExplicitSigningPubkey, InvoiceBuilder},
+};
+#[cfg(c_bindings)]
+use {
+	crate::offers::invoice::{InvoiceWithDerivedSigningPubkeyBuilder, InvoiceWithExplicitSigningPubkeyBuilder},
+};
+
+#[allow(unused_imports)]
 use crate::prelude::*;
 
 /// Tag for the hash function used when signing an [`InvoiceRequest`]'s merkle root.
@@ -218,8 +227,8 @@ macro_rules! invoice_request_derived_payer_id_builder_methods { (
 		let secp_ctx = secp_ctx.unwrap();
 		let keys = keys.unwrap();
 		let invoice_request = unsigned_invoice_request
-			.sign::<_, Infallible>(
-				|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
+			.sign(|message: &UnsignedInvoiceRequest|
+				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
 			)
 			.unwrap();
 		Ok(invoice_request)
@@ -294,7 +303,7 @@ macro_rules! invoice_request_builder_methods { (
 	}
 
 	fn build_with_checks($($self_mut)* $self: $self_type) -> Result<
-		(UnsignedInvoiceRequest, Option<KeyPair>, Option<&'b Secp256k1<$secp_context>>),
+		(UnsignedInvoiceRequest, Option<Keypair>, Option<&'b Secp256k1<$secp_context>>),
 		Bolt12SemanticError
 	> {
 		#[cfg(feature = "std")] {
@@ -325,7 +334,7 @@ macro_rules! invoice_request_builder_methods { (
 	}
 
 	fn build_without_checks($($self_mut)* $self: $self_type) ->
-		(UnsignedInvoiceRequest, Option<KeyPair>, Option<&'b Secp256k1<$secp_context>>)
+		(UnsignedInvoiceRequest, Option<Keypair>, Option<&'b Secp256k1<$secp_context>>)
 	{
 		// Create the metadata for stateless verification of a Bolt12Invoice.
 		let mut keys = None;
@@ -478,12 +487,37 @@ for InvoiceRequestBuilder<'a, 'b, DerivedPayerId, secp256k1::All> {
 ///
 /// This is serialized as a TLV stream, which includes TLV records from the originating message. As
 /// such, it may include unknown, odd TLV records.
+#[derive(Clone)]
 pub struct UnsignedInvoiceRequest {
 	bytes: Vec<u8>,
 	contents: InvoiceRequestContents,
 	tagged_hash: TaggedHash,
 }
 
+/// A function for signing an [`UnsignedInvoiceRequest`].
+pub trait SignInvoiceRequestFn {
+	/// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream.
+	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()>;
+}
+
+impl<F> SignInvoiceRequestFn for F
+where
+	F: Fn(&UnsignedInvoiceRequest) -> Result<Signature, ()>,
+{
+	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()> {
+		self(message)
+	}
+}
+
+impl<F> SignFn<UnsignedInvoiceRequest> for F
+where
+	F: SignInvoiceRequestFn,
+{
+	fn sign(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()> {
+		self.sign_invoice_request(message)
+	}
+}
+
 impl UnsignedInvoiceRequest {
 	fn new(offer: &Offer, contents: InvoiceRequestContents) -> Self {
 		// Use the offer bytes instead of the offer TLV stream as the offer may have contained
@@ -496,7 +530,7 @@ impl UnsignedInvoiceRequest {
 		let mut bytes = Vec::new();
 		unsigned_tlv_stream.write(&mut bytes).unwrap();
 
-		let tagged_hash = TaggedHash::new(SIGNATURE_TAG, &bytes);
+		let tagged_hash = TaggedHash::from_valid_tlv_stream_bytes(SIGNATURE_TAG, &bytes);
 
 		Self { bytes, contents, tagged_hash }
 	}
@@ -513,12 +547,9 @@ macro_rules! unsigned_invoice_request_sign_method { (
 	/// Signs the [`TaggedHash`] of the invoice request using the given function.
 	///
 	/// Note: The hash computation may have included unknown, odd TLV records.
-	///
-	/// This is not exported to bindings users as functions are not yet mapped.
-	pub fn sign<F, E>($($self_mut)* $self: $self_type, sign: F) -> Result<InvoiceRequest, SignError<E>>
-	where
-		F: FnOnce(&Self) -> Result<Signature, E>
-	{
+	pub fn sign<F: SignInvoiceRequestFn>(
+		$($self_mut)* $self: $self_type, sign: F
+	) -> Result<InvoiceRequest, SignError> {
 		let pubkey = $self.contents.payer_id;
 		let signature = merkle::sign_message(sign, &$self, pubkey)?;
 
@@ -577,6 +608,9 @@ pub struct InvoiceRequest {
 /// ways to respond depending on whether the signing keys were derived.
 #[derive(Clone, Debug)]
 pub struct VerifiedInvoiceRequest {
+	/// The identifier of the [`Offer`] for which the [`InvoiceRequest`] was made.
+	pub offer_id: OfferId,
+
 	/// The verified request.
 	inner: InvoiceRequest,
 
@@ -588,7 +622,7 @@ pub struct VerifiedInvoiceRequest {
 	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 	/// [`respond_using_derived_keys`]: Self::respond_using_derived_keys
 	/// [`respond_with`]: Self::respond_with
-	pub keys: Option<KeyPair>,
+	pub keys: Option<Keypair>,
 }
 
 /// The contents of an [`InvoiceRequest`], which may be shared with an [`Bolt12Invoice`].
@@ -662,35 +696,25 @@ impl UnsignedInvoiceRequest {
 	invoice_request_accessors!(self, self.contents);
 }
 
-impl InvoiceRequest {
-	offer_accessors!(self, self.contents.inner.offer);
-	invoice_request_accessors!(self, self.contents);
-
-	/// Signature of the invoice request using [`payer_id`].
-	///
-	/// [`payer_id`]: Self::payer_id
-	pub fn signature(&self) -> Signature {
-		self.signature
-	}
-
+macro_rules! invoice_request_respond_with_explicit_signing_pubkey_methods { (
+	$self: ident, $contents: expr, $builder: ty
+) => {
 	/// Creates an [`InvoiceBuilder`] for the request with the given required fields and using the
 	/// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
 	///
 	/// See [`InvoiceRequest::respond_with_no_std`] for further details where the aforementioned
 	/// creation time is used for the `created_at` parameter.
 	///
-	/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-	///
 	/// [`Duration`]: core::time::Duration
 	#[cfg(feature = "std")]
 	pub fn respond_with(
-		&self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash
-	) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, Bolt12SemanticError> {
+		&$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash
+	) -> Result<$builder, Bolt12SemanticError> {
 		let created_at = std::time::SystemTime::now()
 			.duration_since(std::time::SystemTime::UNIX_EPOCH)
 			.expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 
-		self.respond_with_no_std(payment_paths, payment_hash, created_at)
+		$contents.respond_with_no_std(payment_paths, payment_hash, created_at)
 	}
 
 	/// Creates an [`InvoiceBuilder`] for the request with the given required fields.
@@ -714,36 +738,93 @@ impl InvoiceRequest {
 	/// If the originating [`Offer`] was created using [`OfferBuilder::deriving_signing_pubkey`],
 	/// then use [`InvoiceRequest::verify`] and [`VerifiedInvoiceRequest`] methods instead.
 	///
-	/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-	///
 	/// [`Bolt12Invoice::created_at`]: crate::offers::invoice::Bolt12Invoice::created_at
 	/// [`OfferBuilder::deriving_signing_pubkey`]: crate::offers::offer::OfferBuilder::deriving_signing_pubkey
 	pub fn respond_with_no_std(
-		&self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+		&$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 		created_at: core::time::Duration
-	) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, Bolt12SemanticError> {
-		if self.invoice_request_features().requires_unknown_bits() {
+	) -> Result<$builder, Bolt12SemanticError> {
+		if $contents.invoice_request_features().requires_unknown_bits() {
 			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 		}
 
-		InvoiceBuilder::for_offer(self, payment_paths, created_at, payment_hash)
+		let signing_pubkey = match $contents.contents.inner.offer.signing_pubkey() {
+			Some(signing_pubkey) => signing_pubkey,
+			None => return Err(Bolt12SemanticError::MissingSigningPubkey),
+		};
+
+		<$builder>::for_offer(&$contents, payment_paths, created_at, payment_hash, signing_pubkey)
 	}
 
+	#[cfg(test)]
+	#[allow(dead_code)]
+	pub(super) fn respond_with_no_std_using_signing_pubkey(
+		&$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+		created_at: core::time::Duration, signing_pubkey: PublicKey
+	) -> Result<$builder, Bolt12SemanticError> {
+		debug_assert!($contents.contents.inner.offer.signing_pubkey().is_none());
+
+		if $contents.invoice_request_features().requires_unknown_bits() {
+			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
+		}
+
+		<$builder>::for_offer(&$contents, payment_paths, created_at, payment_hash, signing_pubkey)
+	}
+} }
+
+macro_rules! invoice_request_verify_method { ($self: ident, $self_type: ty) => {
 	/// Verifies that the request was for an offer created using the given key. Returns the verified
 	/// request which contains the derived keys needed to sign a [`Bolt12Invoice`] for the request
 	/// if they could be extracted from the metadata.
 	///
 	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
-	pub fn verify<T: secp256k1::Signing>(
-		self, key: &ExpandedKey, secp_ctx: &Secp256k1<T>
+	pub fn verify<
+		#[cfg(not(c_bindings))]
+		T: secp256k1::Signing
+	>(
+		$self: $self_type, key: &ExpandedKey,
+		#[cfg(not(c_bindings))]
+		secp_ctx: &Secp256k1<T>,
+		#[cfg(c_bindings)]
+		secp_ctx: &Secp256k1<secp256k1::All>,
 	) -> Result<VerifiedInvoiceRequest, ()> {
-		let keys = self.contents.inner.offer.verify(&self.bytes, key, secp_ctx)?;
+		let (offer_id, keys) = $self.contents.inner.offer.verify(&$self.bytes, key, secp_ctx)?;
 		Ok(VerifiedInvoiceRequest {
-			inner: self,
+			offer_id,
+			#[cfg(not(c_bindings))]
+			inner: $self,
+			#[cfg(c_bindings)]
+			inner: $self.clone(),
 			keys,
 		})
 	}
 
+} }
+
+#[cfg(not(c_bindings))]
+impl InvoiceRequest {
+	offer_accessors!(self, self.contents.inner.offer);
+	invoice_request_accessors!(self, self.contents);
+	invoice_request_respond_with_explicit_signing_pubkey_methods!(self, self, InvoiceBuilder<ExplicitSigningPubkey>);
+	invoice_request_verify_method!(self, Self);
+}
+
+#[cfg(c_bindings)]
+impl InvoiceRequest {
+	offer_accessors!(self, self.contents.inner.offer);
+	invoice_request_accessors!(self, self.contents);
+	invoice_request_respond_with_explicit_signing_pubkey_methods!(self, self, InvoiceWithExplicitSigningPubkeyBuilder);
+	invoice_request_verify_method!(self, &Self);
+}
+
+impl InvoiceRequest {
+	/// Signature of the invoice request using [`payer_id`].
+	///
+	/// [`payer_id`]: Self::payer_id
+	pub fn signature(&self) -> Signature {
+		self.signature
+	}
+
 	pub(crate) fn as_tlv_stream(&self) -> FullInvoiceRequestTlvStreamRef {
 		let (payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream) =
 			self.contents.as_tlv_stream();
@@ -754,55 +835,25 @@ impl InvoiceRequest {
 	}
 }
 
-impl VerifiedInvoiceRequest {
-	offer_accessors!(self, self.inner.contents.inner.offer);
-	invoice_request_accessors!(self, self.inner.contents);
-
-	/// Creates an [`InvoiceBuilder`] for the request with the given required fields and using the
-	/// [`Duration`] since [`std::time::SystemTime::UNIX_EPOCH`] as the creation time.
-	///
-	/// See [`InvoiceRequest::respond_with_no_std`] for further details.
-	///
-	/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-	///
-	/// [`Duration`]: core::time::Duration
-	#[cfg(feature = "std")]
-	pub fn respond_with(
-		&self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash
-	) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, Bolt12SemanticError> {
-		self.inner.respond_with(payment_paths, payment_hash)
-	}
-
-	/// Creates an [`InvoiceBuilder`] for the request with the given required fields.
-	///
-	/// See [`InvoiceRequest::respond_with_no_std`] for further details.
-	///
-	/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-	pub fn respond_with_no_std(
-		&self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
-		created_at: core::time::Duration
-	) -> Result<InvoiceBuilder<ExplicitSigningPubkey>, Bolt12SemanticError> {
-		self.inner.respond_with_no_std(payment_paths, payment_hash, created_at)
-	}
-
+macro_rules! invoice_request_respond_with_derived_signing_pubkey_methods { (
+	$self: ident, $contents: expr, $builder: ty
+) => {
 	/// Creates an [`InvoiceBuilder`] for the request using the given required fields and that uses
 	/// derived signing keys from the originating [`Offer`] to sign the [`Bolt12Invoice`]. Must use
 	/// the same [`ExpandedKey`] as the one used to create the offer.
 	///
 	/// See [`InvoiceRequest::respond_with`] for further details.
 	///
-	/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-	///
 	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 	#[cfg(feature = "std")]
 	pub fn respond_using_derived_keys(
-		&self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash
-	) -> Result<InvoiceBuilder<DerivedSigningPubkey>, Bolt12SemanticError> {
+		&$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash
+	) -> Result<$builder, Bolt12SemanticError> {
 		let created_at = std::time::SystemTime::now()
 			.duration_since(std::time::SystemTime::UNIX_EPOCH)
 			.expect("SystemTime::now() should come after SystemTime::UNIX_EPOCH");
 
-		self.respond_using_derived_keys_no_std(payment_paths, payment_hash, created_at)
+		$self.respond_using_derived_keys_no_std(payment_paths, payment_hash, created_at)
 	}
 
 	/// Creates an [`InvoiceBuilder`] for the request using the given required fields and that uses
@@ -811,26 +862,58 @@ impl VerifiedInvoiceRequest {
 	///
 	/// See [`InvoiceRequest::respond_with_no_std`] for further details.
 	///
-	/// This is not exported to bindings users as builder patterns don't map outside of move semantics.
-	///
 	/// [`Bolt12Invoice`]: crate::offers::invoice::Bolt12Invoice
 	pub fn respond_using_derived_keys_no_std(
-		&self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
+		&$self, payment_paths: Vec<(BlindedPayInfo, BlindedPath)>, payment_hash: PaymentHash,
 		created_at: core::time::Duration
-	) -> Result<InvoiceBuilder<DerivedSigningPubkey>, Bolt12SemanticError> {
-		if self.inner.invoice_request_features().requires_unknown_bits() {
+	) -> Result<$builder, Bolt12SemanticError> {
+		if $self.inner.invoice_request_features().requires_unknown_bits() {
 			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 		}
 
-		let keys = match self.keys {
+		let keys = match $self.keys {
 			None => return Err(Bolt12SemanticError::InvalidMetadata),
 			Some(keys) => keys,
 		};
 
-		InvoiceBuilder::for_offer_using_keys(
-			&self.inner, payment_paths, created_at, payment_hash, keys
+		match $contents.contents.inner.offer.signing_pubkey() {
+			Some(signing_pubkey) => debug_assert_eq!(signing_pubkey, keys.public_key()),
+			None => return Err(Bolt12SemanticError::MissingSigningPubkey),
+		}
+
+		<$builder>::for_offer_using_keys(
+			&$self.inner, payment_paths, created_at, payment_hash, keys
 		)
 	}
+} }
+
+impl VerifiedInvoiceRequest {
+	offer_accessors!(self, self.inner.contents.inner.offer);
+	invoice_request_accessors!(self, self.inner.contents);
+	#[cfg(not(c_bindings))]
+	invoice_request_respond_with_explicit_signing_pubkey_methods!(self, self.inner, InvoiceBuilder<ExplicitSigningPubkey>);
+	#[cfg(c_bindings)]
+	invoice_request_respond_with_explicit_signing_pubkey_methods!(self, self.inner, InvoiceWithExplicitSigningPubkeyBuilder);
+	#[cfg(not(c_bindings))]
+	invoice_request_respond_with_derived_signing_pubkey_methods!(self, self.inner, InvoiceBuilder<DerivedSigningPubkey>);
+	#[cfg(c_bindings)]
+	invoice_request_respond_with_derived_signing_pubkey_methods!(self, self.inner, InvoiceWithDerivedSigningPubkeyBuilder);
+
+	pub(crate) fn fields(&self) -> InvoiceRequestFields {
+		let InvoiceRequestContents {
+			payer_id,
+			inner: InvoiceRequestContentsWithoutPayerId {
+				payer: _, offer: _, chain: _, amount_msats: _, features: _, quantity, payer_note
+			},
+		} = &self.inner.contents;
+
+		InvoiceRequestFields {
+			payer_id: *payer_id,
+			quantity: *quantity,
+			payer_note_truncated: payer_note.clone()
+				.map(|mut s| { s.truncate(PAYER_NOTE_LIMIT); UntrustedString(s) }),
+		}
+	}
 }
 
 impl InvoiceRequestContents {
@@ -902,6 +985,7 @@ impl InvoiceRequestContentsWithoutPayerId {
 			quantity: self.quantity,
 			payer_id: None,
 			payer_note: self.payer_note.as_ref(),
+			paths: None,
 		};
 
 		(payer, offer, invoice_request)
@@ -934,6 +1018,8 @@ pub(super) const INVOICE_REQUEST_TYPES: core::ops::Range<u64> = 80..160;
 /// [`Refund::payer_id`]: crate::offers::refund::Refund::payer_id
 pub(super) const INVOICE_REQUEST_PAYER_ID_TYPE: u64 = 88;
 
+// This TLV stream is used for both InvoiceRequest and Refund, but not all TLV records are valid for
+// InvoiceRequest as noted below.
 tlv_stream!(InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef, INVOICE_REQUEST_TYPES, {
 	(80, chain: ChainHash),
 	(82, amount: (u64, HighZeroBytesDroppedBigSize)),
@@ -941,6 +1027,8 @@ tlv_stream!(InvoiceRequestTlvStream, InvoiceRequestTlvStreamRef, INVOICE_REQUEST
 	(86, quantity: (u64, HighZeroBytesDroppedBigSize)),
 	(INVOICE_REQUEST_PAYER_ID_TYPE, payer_id: PublicKey),
 	(89, payer_note: (String, WithoutLength)),
+	// Only used for Refund since the onion message of an InvoiceRequest has a reply path.
+	(90, paths: (Vec<BlindedPath>, WithoutLength)),
 });
 
 type FullInvoiceRequestTlvStream =
@@ -985,7 +1073,7 @@ impl TryFrom<Vec<u8>> for UnsignedInvoiceRequest {
 			(payer_tlv_stream, offer_tlv_stream, invoice_request_tlv_stream)
 		)?;
 
-		let tagged_hash = TaggedHash::new(SIGNATURE_TAG, &bytes);
+		let tagged_hash = TaggedHash::from_valid_tlv_stream_bytes(SIGNATURE_TAG, &bytes);
 
 		Ok(UnsignedInvoiceRequest { bytes, contents, tagged_hash })
 	}
@@ -1009,7 +1097,7 @@ impl TryFrom<Vec<u8>> for InvoiceRequest {
 			None => return Err(Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingSignature)),
 			Some(signature) => signature,
 		};
-		let message = TaggedHash::new(SIGNATURE_TAG, &bytes);
+		let message = TaggedHash::from_valid_tlv_stream_bytes(SIGNATURE_TAG, &bytes);
 		merkle::verify_signature(&signature, &message, contents.payer_id)?;
 
 		Ok(InvoiceRequest { bytes, contents, signature })
@@ -1023,7 +1111,9 @@ impl TryFrom<PartialInvoiceRequestTlvStream> for InvoiceRequestContents {
 		let (
 			PayerTlvStream { metadata },
 			offer_tlv_stream,
-			InvoiceRequestTlvStream { chain, amount, features, quantity, payer_id, payer_note },
+			InvoiceRequestTlvStream {
+				chain, amount, features, quantity, payer_id, payer_note, paths,
+			},
 		) = tlv_stream;
 
 		let payer = match metadata {
@@ -1050,6 +1140,10 @@ impl TryFrom<PartialInvoiceRequestTlvStream> for InvoiceRequestContents {
 			Some(payer_id) => payer_id,
 		};
 
+		if paths.is_some() {
+			return Err(Bolt12SemanticError::UnexpectedPaths);
+		}
+
 		Ok(InvoiceRequestContents {
 			inner: InvoiceRequestContentsWithoutPayerId {
 				payer, offer, chain, amount_msats: amount, features, quantity, payer_note,
@@ -1059,14 +1153,59 @@ impl TryFrom<PartialInvoiceRequestTlvStream> for InvoiceRequestContents {
 	}
 }
 
+/// Fields sent in an [`InvoiceRequest`] message to include in [`PaymentContext::Bolt12Offer`].
+///
+/// [`PaymentContext::Bolt12Offer`]: crate::blinded_path::payment::PaymentContext::Bolt12Offer
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct InvoiceRequestFields {
+	/// A possibly transient pubkey used to sign the invoice request.
+	pub payer_id: PublicKey,
+
+	/// The quantity of the offer's item conforming to [`Offer::is_valid_quantity`].
+	pub quantity: Option<u64>,
+
+	/// A payer-provided note which will be seen by the recipient and reflected back in the invoice
+	/// response. Truncated to [`PAYER_NOTE_LIMIT`] characters.
+	pub payer_note_truncated: Option<UntrustedString>,
+}
+
+/// The maximum number of characters included in [`InvoiceRequestFields::payer_note_truncated`].
+pub const PAYER_NOTE_LIMIT: usize = 512;
+
+impl Writeable for InvoiceRequestFields {
+	fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+		write_tlv_fields!(writer, {
+			(0, self.payer_id, required),
+			(2, self.quantity.map(|v| HighZeroBytesDroppedBigSize(v)), option),
+			(4, self.payer_note_truncated.as_ref().map(|s| WithoutLength(&s.0)), option),
+		});
+		Ok(())
+	}
+}
+
+impl Readable for InvoiceRequestFields {
+	fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+		_init_and_read_len_prefixed_tlv_fields!(reader, {
+			(0, payer_id, required),
+			(2, quantity, (option, encoding: (u64, HighZeroBytesDroppedBigSize))),
+			(4, payer_note_truncated, (option, encoding: (String, WithoutLength))),
+		});
+
+		Ok(InvoiceRequestFields {
+			payer_id: payer_id.0.unwrap(),
+			quantity,
+			payer_note_truncated: payer_note_truncated.map(|s| UntrustedString(s)),
+		})
+	}
+}
+
 #[cfg(test)]
 mod tests {
-	use super::{InvoiceRequest, InvoiceRequestTlvStreamRef, SIGNATURE_TAG, UnsignedInvoiceRequest};
+	use super::{InvoiceRequest, InvoiceRequestFields, InvoiceRequestTlvStreamRef, PAYER_NOTE_LIMIT, SIGNATURE_TAG, UnsignedInvoiceRequest};
 
 	use bitcoin::blockdata::constants::ChainHash;
-	use bitcoin::network::constants::Network;
-	use bitcoin::secp256k1::{KeyPair, Secp256k1, SecretKey, self};
-	use core::convert::{Infallible, TryFrom};
+	use bitcoin::network::Network;
+	use bitcoin::secp256k1::{Keypair, Secp256k1, SecretKey, self};
 	use core::num::NonZeroU64;
 	#[cfg(feature = "std")]
 	use core::time::Duration;
@@ -1089,12 +1228,12 @@ mod tests {
 	use crate::offers::parse::{Bolt12ParseError, Bolt12SemanticError};
 	use crate::offers::payer::PayerTlvStreamRef;
 	use crate::offers::test_utils::*;
-	use crate::util::ser::{BigSize, Writeable};
-	use crate::util::string::PrintableString;
+	use crate::util::ser::{BigSize, Readable, Writeable};
+	use crate::util::string::{PrintableString, UntrustedString};
 
 	#[test]
 	fn builds_invoice_request_with_defaults() {
-		let unsigned_invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let unsigned_invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1109,14 +1248,14 @@ mod tests {
 		assert_eq!(unsigned_invoice_request.payer_metadata(), &[1; 32]);
 		assert_eq!(unsigned_invoice_request.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 		assert_eq!(unsigned_invoice_request.metadata(), None);
-		assert_eq!(unsigned_invoice_request.amount(), Some(&Amount::Bitcoin { amount_msats: 1000 }));
-		assert_eq!(unsigned_invoice_request.description(), PrintableString("foo"));
+		assert_eq!(unsigned_invoice_request.amount(), Some(Amount::Bitcoin { amount_msats: 1000 }));
+		assert_eq!(unsigned_invoice_request.description(), Some(PrintableString("")));
 		assert_eq!(unsigned_invoice_request.offer_features(), &OfferFeatures::empty());
 		assert_eq!(unsigned_invoice_request.absolute_expiry(), None);
 		assert_eq!(unsigned_invoice_request.paths(), &[]);
 		assert_eq!(unsigned_invoice_request.issuer(), None);
 		assert_eq!(unsigned_invoice_request.supported_quantity(), Quantity::One);
-		assert_eq!(unsigned_invoice_request.signing_pubkey(), recipient_pubkey());
+		assert_eq!(unsigned_invoice_request.signing_pubkey(), Some(recipient_pubkey()));
 		assert_eq!(unsigned_invoice_request.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 		assert_eq!(unsigned_invoice_request.amount_msats(), None);
 		assert_eq!(unsigned_invoice_request.invoice_request_features(), &InvoiceRequestFeatures::empty());
@@ -1141,14 +1280,14 @@ mod tests {
 		assert_eq!(invoice_request.payer_metadata(), &[1; 32]);
 		assert_eq!(invoice_request.chains(), vec![ChainHash::using_genesis_block(Network::Bitcoin)]);
 		assert_eq!(invoice_request.metadata(), None);
-		assert_eq!(invoice_request.amount(), Some(&Amount::Bitcoin { amount_msats: 1000 }));
-		assert_eq!(invoice_request.description(), PrintableString("foo"));
+		assert_eq!(invoice_request.amount(), Some(Amount::Bitcoin { amount_msats: 1000 }));
+		assert_eq!(invoice_request.description(), Some(PrintableString("")));
 		assert_eq!(invoice_request.offer_features(), &OfferFeatures::empty());
 		assert_eq!(invoice_request.absolute_expiry(), None);
 		assert_eq!(invoice_request.paths(), &[]);
 		assert_eq!(invoice_request.issuer(), None);
 		assert_eq!(invoice_request.supported_quantity(), Quantity::One);
-		assert_eq!(invoice_request.signing_pubkey(), recipient_pubkey());
+		assert_eq!(invoice_request.signing_pubkey(), Some(recipient_pubkey()));
 		assert_eq!(invoice_request.chain(), ChainHash::using_genesis_block(Network::Bitcoin));
 		assert_eq!(invoice_request.amount_msats(), None);
 		assert_eq!(invoice_request.invoice_request_features(), &InvoiceRequestFeatures::empty());
@@ -1156,7 +1295,7 @@ mod tests {
 		assert_eq!(invoice_request.payer_id(), payer_pubkey());
 		assert_eq!(invoice_request.payer_note(), None);
 
-		let message = TaggedHash::new(SIGNATURE_TAG, &invoice_request.bytes);
+		let message = TaggedHash::from_valid_tlv_stream_bytes(SIGNATURE_TAG, &invoice_request.bytes);
 		assert!(merkle::verify_signature(&invoice_request.signature, &message, payer_pubkey()).is_ok());
 
 		assert_eq!(
@@ -1168,7 +1307,7 @@ mod tests {
 					metadata: None,
 					currency: None,
 					amount: Some(1000),
-					description: Some(&String::from("foo")),
+					description: Some(&String::from("")),
 					features: None,
 					absolute_expiry: None,
 					paths: None,
@@ -1183,6 +1322,7 @@ mod tests {
 					quantity: None,
 					payer_id: Some(&payer_pubkey()),
 					payer_note: None,
+					paths: None,
 				},
 				SignatureTlvStreamRef { signature: Some(&invoice_request.signature()) },
 			),
@@ -1199,7 +1339,7 @@ mod tests {
 		let future_expiry = Duration::from_secs(u64::max_value());
 		let past_expiry = Duration::from_secs(0);
 
-		if let Err(e) = OfferBuilder::new("foo".into(), recipient_pubkey())
+		if let Err(e) = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.absolute_expiry(future_expiry)
 			.build().unwrap()
@@ -1209,7 +1349,7 @@ mod tests {
 			panic!("error building invoice_request: {:?}", e);
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.absolute_expiry(past_expiry)
 			.build().unwrap()
@@ -1229,7 +1369,7 @@ mod tests {
 		let secp_ctx = Secp256k1::new();
 		let payment_id = PaymentId([1; 32]);
 
-		let offer = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let offer = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap();
 		let invoice_request = offer
@@ -1261,7 +1401,7 @@ mod tests {
 		let mut bytes = Vec::new();
 		tlv_stream.write(&mut bytes).unwrap();
 
-		let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
+		let message = TaggedHash::from_valid_tlv_stream_bytes(INVOICE_SIGNATURE_TAG, &bytes);
 		let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
 		signature_tlv_stream.signature = Some(&signature);
 
@@ -1284,7 +1424,7 @@ mod tests {
 		let mut bytes = Vec::new();
 		tlv_stream.write(&mut bytes).unwrap();
 
-		let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
+		let message = TaggedHash::from_valid_tlv_stream_bytes(INVOICE_SIGNATURE_TAG, &bytes);
 		let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
 		signature_tlv_stream.signature = Some(&signature);
 
@@ -1302,7 +1442,7 @@ mod tests {
 		let secp_ctx = Secp256k1::new();
 		let payment_id = PaymentId([1; 32]);
 
-		let offer = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let offer = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap();
 		let invoice_request = offer
@@ -1333,7 +1473,7 @@ mod tests {
 		let mut bytes = Vec::new();
 		tlv_stream.write(&mut bytes).unwrap();
 
-		let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
+		let message = TaggedHash::from_valid_tlv_stream_bytes(INVOICE_SIGNATURE_TAG, &bytes);
 		let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
 		signature_tlv_stream.signature = Some(&signature);
 
@@ -1356,7 +1496,7 @@ mod tests {
 		let mut bytes = Vec::new();
 		tlv_stream.write(&mut bytes).unwrap();
 
-		let message = TaggedHash::new(INVOICE_SIGNATURE_TAG, &bytes);
+		let message = TaggedHash::from_valid_tlv_stream_bytes(INVOICE_SIGNATURE_TAG, &bytes);
 		let signature = merkle::sign_message(recipient_sign, &message, recipient_pubkey()).unwrap();
 		signature_tlv_stream.signature = Some(&signature);
 
@@ -1372,7 +1512,7 @@ mod tests {
 		let mainnet = ChainHash::using_genesis_block(Network::Bitcoin);
 		let testnet = ChainHash::using_genesis_block(Network::Testnet);
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1383,7 +1523,7 @@ mod tests {
 		assert_eq!(invoice_request.chain(), mainnet);
 		assert_eq!(tlv_stream.chain, None);
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.chain(Network::Testnet)
 			.build().unwrap()
@@ -1395,7 +1535,7 @@ mod tests {
 		assert_eq!(invoice_request.chain(), testnet);
 		assert_eq!(tlv_stream.chain, Some(&testnet));
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.chain(Network::Bitcoin)
 			.chain(Network::Testnet)
@@ -1408,7 +1548,7 @@ mod tests {
 		assert_eq!(invoice_request.chain(), mainnet);
 		assert_eq!(tlv_stream.chain, None);
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.chain(Network::Bitcoin)
 			.chain(Network::Testnet)
@@ -1422,7 +1562,7 @@ mod tests {
 		assert_eq!(invoice_request.chain(), testnet);
 		assert_eq!(tlv_stream.chain, Some(&testnet));
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.chain(Network::Testnet)
 			.build().unwrap()
@@ -1433,7 +1573,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::UnsupportedChain),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.chain(Network::Testnet)
 			.build().unwrap()
@@ -1447,7 +1587,7 @@ mod tests {
 
 	#[test]
 	fn builds_invoice_request_with_amount() {
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1458,7 +1598,7 @@ mod tests {
 		assert_eq!(invoice_request.amount_msats(), Some(1000));
 		assert_eq!(tlv_stream.amount, Some(1000));
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1470,7 +1610,7 @@ mod tests {
 		assert_eq!(invoice_request.amount_msats(), Some(1000));
 		assert_eq!(tlv_stream.amount, Some(1000));
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1481,7 +1621,7 @@ mod tests {
 		assert_eq!(invoice_request.amount_msats(), Some(1001));
 		assert_eq!(tlv_stream.amount, Some(1001));
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1491,7 +1631,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::InsufficientAmount),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1503,7 +1643,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::InsufficientAmount),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1513,7 +1653,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidAmount),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1526,7 +1666,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::InsufficientAmount),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 			.build()
@@ -1535,7 +1675,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::MissingAmount),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1550,7 +1690,7 @@ mod tests {
 
 	#[test]
 	fn builds_invoice_request_with_features() {
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1561,7 +1701,7 @@ mod tests {
 		assert_eq!(invoice_request.invoice_request_features(), &InvoiceRequestFeatures::unknown());
 		assert_eq!(tlv_stream.features, Some(&InvoiceRequestFeatures::unknown()));
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1579,7 +1719,7 @@ mod tests {
 		let one = NonZeroU64::new(1).unwrap();
 		let ten = NonZeroU64::new(10).unwrap();
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::One)
 			.build().unwrap()
@@ -1590,7 +1730,7 @@ mod tests {
 		assert_eq!(invoice_request.quantity(), None);
 		assert_eq!(tlv_stream.quantity, None);
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::One)
 			.build().unwrap()
@@ -1602,7 +1742,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::UnexpectedQuantity),
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Bounded(ten))
 			.build().unwrap()
@@ -1615,7 +1755,7 @@ mod tests {
 		assert_eq!(invoice_request.amount_msats(), Some(10_000));
 		assert_eq!(tlv_stream.amount, Some(10_000));
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Bounded(ten))
 			.build().unwrap()
@@ -1627,7 +1767,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::InvalidQuantity),
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1640,7 +1780,7 @@ mod tests {
 		assert_eq!(invoice_request.amount_msats(), Some(2_000));
 		assert_eq!(tlv_stream.amount, Some(2_000));
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1651,7 +1791,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12SemanticError::MissingQuantity),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Bounded(one))
 			.build().unwrap()
@@ -1665,7 +1805,7 @@ mod tests {
 
 	#[test]
 	fn builds_invoice_request_with_payer_note() {
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1676,7 +1816,7 @@ mod tests {
 		assert_eq!(invoice_request.payer_note(), Some(PrintableString("bar")));
 		assert_eq!(tlv_stream.payer_note, Some(&String::from("bar")));
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1691,18 +1831,18 @@ mod tests {
 
 	#[test]
 	fn fails_signing_invoice_request() {
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 			.build().unwrap()
-			.sign(|_| Err(()))
+			.sign(fail_sign)
 		{
 			Ok(_) => panic!("expected error"),
-			Err(e) => assert_eq!(e, SignError::Signing(())),
+			Err(e) => assert_eq!(e, SignError::Signing),
 		}
 
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1716,7 +1856,7 @@ mod tests {
 
 	#[test]
 	fn fails_responding_with_unknown_required_features() {
-		match OfferBuilder::new("foo".into(), recipient_pubkey())
+		match OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![42; 32], payer_pubkey()).unwrap()
@@ -1732,7 +1872,7 @@ mod tests {
 
 	#[test]
 	fn parses_invoice_request_with_metadata() {
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1749,7 +1889,7 @@ mod tests {
 
 	#[test]
 	fn parses_invoice_request_with_chain() {
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1764,7 +1904,7 @@ mod tests {
 			panic!("error parsing invoice_request: {:?}", e);
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1783,7 +1923,7 @@ mod tests {
 
 	#[test]
 	fn parses_invoice_request_with_amount() {
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1797,7 +1937,7 @@ mod tests {
 			panic!("error parsing invoice_request: {:?}", e);
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 			.amount_msats(1000).unwrap()
@@ -1811,7 +1951,7 @@ mod tests {
 			panic!("error parsing invoice_request: {:?}", e);
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
 			.build_unchecked()
@@ -1825,7 +1965,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingAmount)),
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1841,7 +1981,8 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InsufficientAmount)),
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
+			.description("foo".to_string())
 			.amount(Amount::Currency { iso4217_code: *b"USD", amount: 1000 })
 			.build_unchecked()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -1858,7 +1999,7 @@ mod tests {
 			},
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1881,7 +2022,7 @@ mod tests {
 		let one = NonZeroU64::new(1).unwrap();
 		let ten = NonZeroU64::new(10).unwrap();
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::One)
 			.build().unwrap()
@@ -1896,7 +2037,7 @@ mod tests {
 			panic!("error parsing invoice_request: {:?}", e);
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::One)
 			.build().unwrap()
@@ -1916,7 +2057,7 @@ mod tests {
 			},
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Bounded(ten))
 			.build().unwrap()
@@ -1933,7 +2074,7 @@ mod tests {
 			panic!("error parsing invoice_request: {:?}", e);
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Bounded(ten))
 			.build().unwrap()
@@ -1951,7 +2092,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::InvalidQuantity)),
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1968,7 +2109,7 @@ mod tests {
 			panic!("error parsing invoice_request: {:?}", e);
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Unbounded)
 			.build().unwrap()
@@ -1984,7 +2125,7 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12ParseError::InvalidSemantics(Bolt12SemanticError::MissingQuantity)),
 		}
 
-		let invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.supported_quantity(Quantity::Bounded(one))
 			.build().unwrap()
@@ -2003,7 +2144,7 @@ mod tests {
 
 	#[test]
 	fn fails_parsing_invoice_request_without_metadata() {
-		let offer = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let offer = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap();
 		let unsigned_invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -2024,7 +2165,7 @@ mod tests {
 
 	#[test]
 	fn fails_parsing_invoice_request_without_payer_id() {
-		let offer = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let offer = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap();
 		let unsigned_invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -2043,7 +2184,7 @@ mod tests {
 
 	#[test]
 	fn fails_parsing_invoice_request_without_node_id() {
-		let offer = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let offer = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap();
 		let unsigned_invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -2065,7 +2206,7 @@ mod tests {
 	#[test]
 	fn fails_parsing_invoice_request_without_signature() {
 		let mut buffer = Vec::new();
-		OfferBuilder::new("foo".into(), recipient_pubkey())
+		OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -2081,7 +2222,7 @@ mod tests {
 
 	#[test]
 	fn fails_parsing_invoice_request_with_invalid_signature() {
-		let mut invoice_request = OfferBuilder::new("foo".into(), recipient_pubkey())
+		let mut invoice_request = OfferBuilder::new(recipient_pubkey())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
@@ -2104,14 +2245,14 @@ mod tests {
 	#[test]
 	fn fails_parsing_invoice_request_with_extra_tlv_records() {
 		let secp_ctx = Secp256k1::new();
-		let keys = KeyPair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
-		let invoice_request = OfferBuilder::new("foo".into(), keys.public_key())
+		let keys = Keypair::from_secret_key(&secp_ctx, &SecretKey::from_slice(&[42; 32]).unwrap());
+		let invoice_request = OfferBuilder::new(keys.public_key())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], keys.public_key()).unwrap()
 			.build().unwrap()
-			.sign::<_, Infallible>(
-				|message| Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
+			.sign(|message: &UnsignedInvoiceRequest|
+				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
 			)
 			.unwrap();
 
@@ -2126,4 +2267,51 @@ mod tests {
 			Err(e) => assert_eq!(e, Bolt12ParseError::Decode(DecodeError::InvalidValue)),
 		}
 	}
+
+	#[test]
+	fn copies_verified_invoice_request_fields() {
+		let node_id = recipient_pubkey();
+		let expanded_key = ExpandedKey::new(&KeyMaterial([42; 32]));
+		let entropy = FixedEntropy {};
+		let secp_ctx = Secp256k1::new();
+
+		#[cfg(c_bindings)]
+		use crate::offers::offer::OfferWithDerivedMetadataBuilder as OfferBuilder;
+		let offer = OfferBuilder
+			::deriving_signing_pubkey(node_id, &expanded_key, &entropy, &secp_ctx)
+			.chain(Network::Testnet)
+			.amount_msats(1000)
+			.supported_quantity(Quantity::Unbounded)
+			.build().unwrap();
+		assert_eq!(offer.signing_pubkey(), Some(node_id));
+
+		let invoice_request = offer.request_invoice(vec![1; 32], payer_pubkey()).unwrap()
+			.chain(Network::Testnet).unwrap()
+			.quantity(1).unwrap()
+			.payer_note("0".repeat(PAYER_NOTE_LIMIT * 2))
+			.build().unwrap()
+			.sign(payer_sign).unwrap();
+		match invoice_request.verify(&expanded_key, &secp_ctx) {
+			Ok(invoice_request) => {
+				let fields = invoice_request.fields();
+				assert_eq!(invoice_request.offer_id, offer.id());
+				assert_eq!(
+					fields,
+					InvoiceRequestFields {
+						payer_id: payer_pubkey(),
+						quantity: Some(1),
+						payer_note_truncated: Some(UntrustedString("0".repeat(PAYER_NOTE_LIMIT))),
+					}
+				);
+
+				let mut buffer = Vec::new();
+				fields.write(&mut buffer).unwrap();
+
+				let deserialized_fields: InvoiceRequestFields =
+					Readable::read(&mut buffer.as_slice()).unwrap();
+				assert_eq!(deserialized_fields, fields);
+			},
+			Err(_) => panic!("unexpected error"),
+		}
+	}
 }