sp-core: Rename VrfOutput to VrfPreOutput (paritytech#2534)

This will make more sense after
paritytech#2524 since the
schnorrkel type for VRF outputs is also renamed in the latest version.
Can be reviewed independently though.

Can be merged after paritytech#1577
so that there is less pain for @davxy.

---------

Co-authored-by: Bastian Köcher <git@kchr.de>

substrate/client/consensus/babe/src/authorship.rs

@@ -249,7 +249,7 @@ fn claim_primary_slot(
 				.make_bytes::<AUTHORING_SCORE_LENGTH>(
 					AUTHORING_SCORE_VRF_CONTEXT,
 					&data.as_ref(),
-					&vrf_signature.output,
+					&vrf_signature.pre_output,
 				)
 				.map(|bytes| u128::from_le_bytes(bytes) < threshold)
 				.unwrap_or_default();

substrate/client/consensus/babe/src/tests.rs

@@ -580,7 +580,7 @@ fn claim_vrf_check() {
 	};
 	let data = make_vrf_sign_data(&epoch.randomness.clone(), 0.into(), epoch.epoch_index);
 	let sign = keystore.sr25519_vrf_sign(AuthorityId::ID, &public, &data).unwrap().unwrap();
-	assert_eq!(pre_digest.vrf_signature.output, sign.output);
+	assert_eq!(pre_digest.vrf_signature.pre_output, sign.pre_output);
 
 	// We expect a SecondaryVRF claim for slot 1
 	let pre_digest = match claim_slot(1.into(), &epoch, &keystore).unwrap().0 {
@@ -589,7 +589,7 @@ fn claim_vrf_check() {
 	};
 	let data = make_vrf_sign_data(&epoch.randomness.clone(), 1.into(), epoch.epoch_index);
 	let sign = keystore.sr25519_vrf_sign(AuthorityId::ID, &public, &data).unwrap().unwrap();
-	assert_eq!(pre_digest.vrf_signature.output, sign.output);
+	assert_eq!(pre_digest.vrf_signature.pre_output, sign.pre_output);
 
 	// Check that correct epoch index has been used if epochs are skipped (primary VRF)
 	let slot = Slot::from(103);
@@ -601,7 +601,7 @@ fn claim_vrf_check() {
 	let data = make_vrf_sign_data(&epoch.randomness.clone(), slot, fixed_epoch.epoch_index);
 	let sign = keystore.sr25519_vrf_sign(AuthorityId::ID, &public, &data).unwrap().unwrap();
 	assert_eq!(fixed_epoch.epoch_index, 11);
-	assert_eq!(claim.vrf_signature.output, sign.output);
+	assert_eq!(claim.vrf_signature.pre_output, sign.pre_output);
 
 	// Check that correct epoch index has been used if epochs are skipped (secondary VRF)
 	let slot = Slot::from(100);
@@ -613,7 +613,7 @@ fn claim_vrf_check() {
 	let data = make_vrf_sign_data(&epoch.randomness.clone(), slot, fixed_epoch.epoch_index);
 	let sign = keystore.sr25519_vrf_sign(AuthorityId::ID, &public, &data).unwrap().unwrap();
 	assert_eq!(fixed_epoch.epoch_index, 11);
-	assert_eq!(pre_digest.vrf_signature.output, sign.output);
+	assert_eq!(pre_digest.vrf_signature.pre_output, sign.pre_output);
 }
 
 // Propose and import a new BABE block on top of the given parent.

substrate/client/consensus/babe/src/verification.rs

@@ -185,7 +185,7 @@ fn check_primary_header<B: BlockT + Sized>(
 		.make_bytes::<AUTHORING_SCORE_LENGTH>(
 			AUTHORING_SCORE_VRF_CONTEXT,
 			&data.as_ref(),
-			&pre_digest.vrf_signature.output,
+			&pre_digest.vrf_signature.pre_output,
 		)
 		.map(u128::from_le_bytes)
 		.map_err(|_| babe_err(Error::VrfVerificationFailed))?;

substrate/client/keystore/src/local.rs

@@ -120,18 +120,18 @@ impl LocalKeystore {
 		Ok(sig)
 	}
 
-	fn vrf_output<T: CorePair + VrfSecret>(
+	fn vrf_pre_output<T: CorePair + VrfSecret>(
 		&self,
 		key_type: KeyTypeId,
 		public: &T::Public,
 		input: &T::VrfInput,
-	) -> std::result::Result<Option<T::VrfOutput>, TraitError> {
-		let preout = self
+	) -> std::result::Result<Option<T::VrfPreOutput>, TraitError> {
+		let pre_output = self
 			.0
 			.read()
 			.key_pair_by_type::<T>(public, key_type)?
-			.map(|pair| pair.vrf_output(input));
-		Ok(preout)
+			.map(|pair| pair.vrf_pre_output(input));
+		Ok(pre_output)
 	}
 }
 
@@ -188,13 +188,13 @@ impl Keystore for LocalKeystore {
 		self.vrf_sign::<sr25519::Pair>(key_type, public, data)
 	}
 
-	fn sr25519_vrf_output(
+	fn sr25519_vrf_pre_output(
 		&self,
 		key_type: KeyTypeId,
 		public: &sr25519::Public,
 		input: &sr25519::vrf::VrfInput,
-	) -> std::result::Result<Option<sr25519::vrf::VrfOutput>, TraitError> {
-		self.vrf_output::<sr25519::Pair>(key_type, public, input)
+	) -> std::result::Result<Option<sr25519::vrf::VrfPreOutput>, TraitError> {
+		self.vrf_pre_output::<sr25519::Pair>(key_type, public, input)
 	}
 
 	fn ed25519_public_keys(&self, key_type: KeyTypeId) -> Vec<ed25519::Public> {
@@ -293,13 +293,13 @@ impl Keystore for LocalKeystore {
 			self.vrf_sign::<bandersnatch::Pair>(key_type, public, data)
 		}
 
-		fn bandersnatch_vrf_output(
+		fn bandersnatch_vrf_pre_output(
 			&self,
 			key_type: KeyTypeId,
 			public: &bandersnatch::Public,
 			input: &bandersnatch::vrf::VrfInput,
-		) -> std::result::Result<Option<bandersnatch::vrf::VrfOutput>, TraitError> {
-			self.vrf_output::<bandersnatch::Pair>(key_type, public, input)
+		) -> std::result::Result<Option<bandersnatch::vrf::VrfPreOutput>, TraitError> {
+			self.vrf_pre_output::<bandersnatch::Pair>(key_type, public, input)
 		}
 
 		fn bandersnatch_ring_vrf_sign(

substrate/frame/babe/src/lib.rs

@@ -384,7 +384,11 @@ pub mod pallet {
 							});
 
 							public
-								.make_bytes(RANDOMNESS_VRF_CONTEXT, &transcript, &signature.output)
+								.make_bytes(
+									RANDOMNESS_VRF_CONTEXT,
+									&transcript,
+									&signature.pre_output,
+								)
 								.ok()
 						});
 

substrate/frame/sassafras/src/lib.rs

@@ -272,11 +272,11 @@ pub mod pallet {
 	#[pallet::storage]
 	pub type RingVerifierData<T: Config> = StorageValue<_, vrf::RingVerifierData>;
 
-	/// Slot claim vrf-preoutput used to generate per-slot randomness.
+	/// Slot claim VRF pre-output used to generate per-slot randomness.
 	///
 	/// The value is ephemeral and is cleared on block finalization.
 	#[pallet::storage]
-	pub(crate) type ClaimTemporaryData<T> = StorageValue<_, vrf::VrfOutput>;
+	pub(crate) type ClaimTemporaryData<T> = StorageValue<_, vrf::VrfPreOutput>;
 
 	/// Genesis configuration for Sassafras protocol.
 	#[pallet::genesis_config]
@@ -324,12 +324,12 @@ pub mod pallet {
 				Self::post_genesis_initialize(claim.slot);
 			}
 
-			let randomness_output = claim
+			let randomness_pre_output = claim
 				.vrf_signature
-				.outputs
+				.pre_outputs
 				.get(0)
-				.expect("Valid claim must have vrf signature; qed");
-			ClaimTemporaryData::<T>::put(randomness_output);
+				.expect("Valid claim must have VRF signature; qed");
+			ClaimTemporaryData::<T>::put(randomness_pre_output);
 
 			let trigger_weight = T::EpochChangeTrigger::trigger::<T>(block_num);
 
@@ -346,9 +346,9 @@ pub mod pallet {
 				CurrentSlot::<T>::get(),
 				EpochIndex::<T>::get(),
 			);
-			let randomness_output = ClaimTemporaryData::<T>::take()
+			let randomness_pre_output = ClaimTemporaryData::<T>::take()
 				.expect("Unconditionally populated in `on_initialize`; `on_finalize` is always called after; qed");
-			let randomness = randomness_output
+			let randomness = randomness_pre_output
 				.make_bytes::<RANDOMNESS_LENGTH>(RANDOMNESS_VRF_CONTEXT, &randomness_input);
 			Self::deposit_slot_randomness(&randomness);
 
@@ -422,15 +422,15 @@ pub mod pallet {
 			for ticket in tickets {
 				debug!(target: LOG_TARGET, "Checking ring proof");
 
-				let Some(ticket_id_output) = ticket.signature.outputs.get(0) else {
-					debug!(target: LOG_TARGET, "Missing ticket vrf output from ring signature");
+				let Some(ticket_id_pre_output) = ticket.signature.pre_outputs.get(0) else {
+					debug!(target: LOG_TARGET, "Missing ticket VRF pre-output from ring signature");
 					continue
 				};
 				let ticket_id_input =
 					vrf::ticket_id_input(&randomness, ticket.body.attempt_idx, epoch_idx);
 
 				// Check threshold constraint
-				let ticket_id = vrf::make_ticket_id(&ticket_id_input, &ticket_id_output);
+				let ticket_id = vrf::make_ticket_id(&ticket_id_input, &ticket_id_pre_output);
 				if ticket_id >= ticket_threshold {
 					debug!(target: LOG_TARGET, "Ignoring ticket over threshold ({:032x} >= {:032x})", ticket_id, ticket_threshold);
 					continue

substrate/frame/sassafras/src/mock.rs

@@ -190,9 +190,9 @@ pub fn make_ticket_body(attempt_idx: u32, pair: &AuthorityPair) -> (TicketId, Ti
 	let randomness = Sassafras::next_randomness();
 
 	let ticket_id_input = vrf::ticket_id_input(&randomness, attempt_idx, epoch);
-	let ticket_id_output = pair.as_inner_ref().vrf_output(&ticket_id_input);
+	let ticket_id_pre_output = pair.as_inner_ref().vrf_pre_output(&ticket_id_input);
 
-	let id = vrf::make_ticket_id(&ticket_id_input, &ticket_id_output);
+	let id = vrf::make_ticket_id(&ticket_id_input, &ticket_id_pre_output);
 
 	// Make a dummy ephemeral public that hopefully is unique within one test instance.
 	// In the tests, the values within the erased public are just used to compare

substrate/primitives/consensus/babe/src/lib.rs

@@ -33,7 +33,7 @@ use sp_std::vec::Vec;
 use crate::digests::{NextConfigDescriptor, NextEpochDescriptor};
 
 pub use sp_core::sr25519::vrf::{
-	VrfInput, VrfOutput, VrfProof, VrfSignData, VrfSignature, VrfTranscript,
+	VrfInput, VrfPreOutput, VrfProof, VrfSignData, VrfSignature, VrfTranscript,
 };
 
 /// Key type for BABE module.

substrate/primitives/consensus/sassafras/src/vrf.rs

@@ -15,7 +15,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//! Utilities related to VRF input, output and signatures.
+//! Utilities related to VRF input, pre-output and signatures.
 
 use crate::{Randomness, TicketBody, TicketId};
 use scale_codec::Encode;
@@ -24,7 +24,7 @@ use sp_std::vec::Vec;
 
 pub use sp_core::bandersnatch::{
 	ring_vrf::{RingProver, RingVerifier, RingVerifierData, RingVrfSignature},
-	vrf::{VrfInput, VrfOutput, VrfSignData, VrfSignature},
+	vrf::{VrfInput, VrfPreOutput, VrfSignData, VrfSignature},
 };
 
 /// Ring VRF domain size for Sassafras consensus.
@@ -90,21 +90,21 @@ pub fn ticket_body_sign_data(ticket_body: &TicketBody, ticket_id_input: VrfInput
 	)
 }
 
-/// Make ticket-id from the given VRF input and output.
+/// Make ticket-id from the given VRF input and pre-output.
 ///
 /// Input should have been obtained via [`ticket_id_input`].
-/// Output should have been obtained from the input directly using the vrf secret key
-/// or from the vrf signature outputs.
-pub fn make_ticket_id(input: &VrfInput, output: &VrfOutput) -> TicketId {
-	let bytes = output.make_bytes::<16>(b"ticket-id", input);
+/// Pre-output should have been obtained from the input directly using the vrf
+/// secret key or from the vrf signature pre-outputs.
+pub fn make_ticket_id(input: &VrfInput, pre_output: &VrfPreOutput) -> TicketId {
+	let bytes = pre_output.make_bytes::<16>(b"ticket-id", input);
 	u128::from_le_bytes(bytes)
 }
 
-/// Make revealed key seed from a given VRF input and ouput.
+/// Make revealed key seed from a given VRF input and pre-ouput.
 ///
 /// Input should have been obtained via [`revealed_key_input`].
-/// Output should have been obtained from the input directly using the vrf secret key
-/// or from the vrf signature outputs.
-pub fn make_revealed_key_seed(input: &VrfInput, output: &VrfOutput) -> [u8; 32] {
-	output.make_bytes::<32>(b"revealed-seed", input)
+/// Pre-output should have been obtained from the input directly using the vrf
+/// secret key or from the vrf signature pre-outputs.
+pub fn make_revealed_key_seed(input: &VrfInput, pre_output: &VrfPreOutput) -> [u8; 32] {
+	pre_output.make_bytes::<32>(b"revealed-seed", input)
 }