X-Git-Url: http://git.bitcoin.ninja/index.cgi?a=blobdiff_plain;f=lightning%2Fsrc%2Foffers%2Finvoice_request.rs;h=faeef26c82f2332b31f6c689e18cd49889cae2af;hb=b8d4ac1371bf0db3b28339d4e12fadf02f6add3d;hp=4eed9fb7ee68f1ef51621c00173998167b56dc1f;hpb=407762446cd4abaab5ea9c1c96e8c181a0f63b86;p=rust-lightning

diff --git a/lightning/src/offers/invoice_request.rs b/lightning/src/offers/invoice_request.rs
index 4eed9fb7..faeef26c 100644
--- a/lightning/src/offers/invoice_request.rs
+++ b/lightning/src/offers/invoice_request.rs
@@ -25,7 +25,6 @@
 //!
 //! use bitcoin::network::constants::Network;
 //! use bitcoin::secp256k1::{KeyPair, PublicKey, Secp256k1, SecretKey};
-//! use core::convert::Infallible;
 //! use lightning::ln::features::OfferFeatures;
 //! use lightning::offers::invoice_request::UnsignedInvoiceRequest;
 //! use lightning::offers::offer::Offer;
@@ -48,9 +47,9 @@
 //!     .quantity(5)?
 //!     .payer_note("foo".to_string())
 //!     .build()?
-//!     .sign(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+//!     .sign(|message: &UnsignedInvoiceRequest|
 //!         Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-//!     })
+//!     )
 //!     .expect("failed verifying signature")
 //!     .write(&mut buffer)
 //!     .unwrap();
@@ -62,24 +61,23 @@ use bitcoin::blockdata::constants::ChainHash;
 use bitcoin::network::constants::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;
 use crate::offers::merkle::{SignError, SignFn, SignatureTlvStream, SignatureTlvStreamRef, TaggedHash, self};
-use crate::offers::offer::{Offer, OfferContents, OfferTlvStream, OfferTlvStreamRef};
+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 {
@@ -90,6 +88,7 @@ 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.
@@ -228,9 +227,9 @@ 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(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+			.sign(|message: &UnsignedInvoiceRequest|
 				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-			})
+			)
 			.unwrap();
 		Ok(invoice_request)
 	}
@@ -496,31 +495,24 @@ pub struct UnsignedInvoiceRequest {
 
 /// A function for signing an [`UnsignedInvoiceRequest`].
 pub trait SignInvoiceRequestFn {
-	/// Error type returned by the function.
-	type Error;
-
 	/// Signs a [`TaggedHash`] computed over the merkle root of `message`'s TLV stream.
-	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, Self::Error>;
+	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()>;
 }
 
-impl<F, E> SignInvoiceRequestFn for F
+impl<F> SignInvoiceRequestFn for F
 where
-	F: Fn(&UnsignedInvoiceRequest) -> Result<Signature, E>,
+	F: Fn(&UnsignedInvoiceRequest) -> Result<Signature, ()>,
 {
-	type Error = E;
-
-	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, E> {
+	fn sign_invoice_request(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()> {
 		self(message)
 	}
 }
 
-impl<F, E> SignFn<UnsignedInvoiceRequest> for F
+impl<F> SignFn<UnsignedInvoiceRequest> for F
 where
-	F: SignInvoiceRequestFn<Error = E>,
+	F: SignInvoiceRequestFn,
 {
-	type Error = E;
-
-	fn sign(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, Self::Error> {
+	fn sign(&self, message: &UnsignedInvoiceRequest) -> Result<Signature, ()> {
 		self.sign_invoice_request(message)
 	}
 }
@@ -537,7 +529,7 @@ 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 }
 	}
@@ -556,7 +548,7 @@ macro_rules! unsigned_invoice_request_sign_method { (
 	/// Note: The hash computation may have included unknown, odd TLV records.
 	pub fn sign<F: SignInvoiceRequestFn>(
 		$($self_mut)* $self: $self_type, sign: F
-	) -> Result<InvoiceRequest, SignError<F::Error>> {
+	) -> Result<InvoiceRequest, SignError> {
 		let pubkey = $self.contents.payer_id;
 		let signature = merkle::sign_message(sign, &$self, pubkey)?;
 
@@ -615,6 +607,9 @@ 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,
 
@@ -752,7 +747,27 @@ macro_rules! invoice_request_respond_with_explicit_signing_pubkey_methods { (
 			return Err(Bolt12SemanticError::UnknownRequiredFeatures);
 		}
 
-		<$builder>::for_offer(&$contents, 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)
 	}
 } }
 
@@ -772,8 +787,9 @@ macro_rules! invoice_request_verify_method { ($self: ident, $self_type: ty) => {
 		#[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 {
+			offer_id,
 			#[cfg(not(c_bindings))]
 			inner: $self,
 			#[cfg(c_bindings)]
@@ -859,6 +875,11 @@ macro_rules! invoice_request_respond_with_derived_signing_pubkey_methods { (
 			Some(keys) => 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
 		)
@@ -876,6 +897,22 @@ impl VerifiedInvoiceRequest {
 	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 {
@@ -947,6 +984,7 @@ impl InvoiceRequestContentsWithoutPayerId {
 			quantity: self.quantity,
 			payer_id: None,
 			payer_note: self.payer_note.as_ref(),
+			paths: None,
 		};
 
 		(payer, offer, invoice_request)
@@ -979,6 +1017,8 @@ 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)),
@@ -986,6 +1026,8 @@ 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 =
@@ -1030,7 +1072,7 @@ 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 })
 	}
@@ -1054,7 +1096,7 @@ 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 })
@@ -1068,7 +1110,9 @@ 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 {
@@ -1095,6 +1139,10 @@ 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,
@@ -1104,14 +1152,59 @@ 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 core::num::NonZeroU64;
 	#[cfg(feature = "std")]
 	use core::time::Duration;
@@ -1134,12 +1227,12 @@ 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()
@@ -1155,13 +1248,13 @@ mod tests {
 		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.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());
@@ -1187,13 +1280,13 @@ mod tests {
 		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.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());
@@ -1201,7 +1294,7 @@ 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!(
@@ -1213,7 +1306,7 @@ 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,
@@ -1228,6 +1321,7 @@ mod tests {
 					quantity: None,
 					payer_id: Some(&payer_pubkey()),
 					payer_note: None,
+					paths: None,
 				},
 				SignatureTlvStreamRef { signature: Some(&invoice_request.signature()) },
 			),
@@ -1244,7 +1338,7 @@ 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()
@@ -1254,7 +1348,7 @@ 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()
@@ -1274,7 +1368,7 @@ 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
@@ -1306,7 +1400,7 @@ 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);
 
@@ -1329,7 +1423,7 @@ 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);
 
@@ -1347,7 +1441,7 @@ 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
@@ -1378,7 +1472,7 @@ 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);
 
@@ -1401,7 +1495,7 @@ 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);
 
@@ -1417,7 +1511,7 @@ 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()
@@ -1428,7 +1522,7 @@ 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()
@@ -1440,7 +1534,7 @@ 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)
@@ -1453,7 +1547,7 @@ 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)
@@ -1467,7 +1561,7 @@ 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()
@@ -1478,7 +1572,7 @@ 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()
@@ -1492,7 +1586,7 @@ 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()
@@ -1503,7 +1597,7 @@ 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()
@@ -1515,7 +1609,7 @@ 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()
@@ -1526,7 +1620,7 @@ 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()
@@ -1536,7 +1630,7 @@ 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()
@@ -1548,7 +1642,7 @@ 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()
@@ -1558,7 +1652,7 @@ 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()
@@ -1571,7 +1665,7 @@ 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()
@@ -1580,7 +1674,7 @@ 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()
@@ -1595,7 +1689,7 @@ 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()
@@ -1606,7 +1700,7 @@ 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()
@@ -1624,7 +1718,7 @@ 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()
@@ -1635,7 +1729,7 @@ 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()
@@ -1647,7 +1741,7 @@ 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()
@@ -1660,7 +1754,7 @@ 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()
@@ -1672,7 +1766,7 @@ 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()
@@ -1685,7 +1779,7 @@ 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()
@@ -1696,7 +1790,7 @@ 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()
@@ -1710,7 +1804,7 @@ 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()
@@ -1721,7 +1815,7 @@ 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()
@@ -1736,7 +1830,7 @@ 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()
@@ -1744,10 +1838,10 @@ mod tests {
 			.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()
@@ -1761,7 +1855,7 @@ 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()
@@ -1777,7 +1871,7 @@ 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()
@@ -1794,7 +1888,7 @@ 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()
@@ -1809,7 +1903,7 @@ 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()
@@ -1828,7 +1922,7 @@ 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()
@@ -1842,7 +1936,7 @@ 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()
@@ -1856,7 +1950,7 @@ 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()
@@ -1870,7 +1964,7 @@ 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()
@@ -1886,7 +1980,8 @@ 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()
@@ -1903,7 +1998,7 @@ 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()
@@ -1926,7 +2021,7 @@ 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()
@@ -1941,7 +2036,7 @@ 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()
@@ -1961,7 +2056,7 @@ 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()
@@ -1978,7 +2073,7 @@ 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()
@@ -1996,7 +2091,7 @@ 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()
@@ -2013,7 +2108,7 @@ 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()
@@ -2029,7 +2124,7 @@ 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()
@@ -2048,7 +2143,7 @@ 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()
@@ -2069,7 +2164,7 @@ 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()
@@ -2088,7 +2183,7 @@ 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()
@@ -2110,7 +2205,7 @@ 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()
@@ -2126,7 +2221,7 @@ 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()
@@ -2150,14 +2245,14 @@ mod tests {
 	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 invoice_request = OfferBuilder::new(keys.public_key())
 			.amount_msats(1000)
 			.build().unwrap()
 			.request_invoice(vec![1; 32], keys.public_key()).unwrap()
 			.build().unwrap()
-			.sign(|message: &UnsignedInvoiceRequest| -> Result<_, Infallible> {
+			.sign(|message: &UnsignedInvoiceRequest|
 				Ok(secp_ctx.sign_schnorr_no_aux_rand(message.as_ref().as_digest(), &keys))
-			})
+			)
 			.unwrap();
 
 		let mut encoded_invoice_request = Vec::new();
@@ -2171,4 +2266,51 @@ 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"),
+		}
+	}
 }