Babe VRF Signing in keystore (#6225)

* Introduce trait * Implement VRFSigner in keystore * Use vrf_sign from keystore * Convert output to VRFInOut * Simplify conversion * vrf_sign secondary slot using keystore * Fix RPC call to claim_slot * Use Public instead of Pair * Check primary threshold in signer * Fix interface to return error * Move vrf_sign to BareCryptoStore * Fix authorship_works test * Fix BABE logic leaks * Acquire a read lock once * Also fix RPC acquiring the read lock once * Implement a generic way to construct VRF Transcript * Use make_transcript_data to call sr25519_vrf_sign * Make sure VRFTranscriptData is serializable * Cleanup * Move VRF to it's own module * Implement & test VRF signing in testing module * Remove leftover * Fix feature requirements * Revert removing vec macro * Drop keystore pointer to prevent deadlock * Nitpicks * Add test to make sure make_transcript works * Fix mismatch in VRF transcript * Add a test to verify transcripts match in babe * Return VRFOutput and VRFProof from keystore
2026-06-14 22:41:06 +00:00 · 2020-06-18 20:37:49 +02:00
parent 4b5a0680e3
commit d25f460b63
15 changed files with 394 additions and 94 deletions
@@ -0,0 +1,99 @@
+// This file is part of Substrate.
+
+// Copyright (C) 2019-2020 Parity Technologies (UK) Ltd.
+// SPDX-License-Identifier: Apache-2.0
+
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 	http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! VRF-specifc data types and helpers
+
+use codec::Encode;
+use merlin::Transcript;
+use schnorrkel::vrf::{VRFOutput, VRFProof};
+/// An enum whose variants represent possible
+/// accepted values to construct the VRF transcript
+#[derive(Clone, Encode)]
+pub enum VRFTranscriptValue<'a> {
+	/// Value is an array of bytes
+	Bytes(&'a [u8]),
+	/// Value is a u64 integer
+	U64(u64),
+}
+/// VRF Transcript data
+#[derive(Clone, Encode)]
+pub struct VRFTranscriptData<'a> {
+	/// The transcript's label
+	pub label: &'static [u8],
+	/// Additional data to be registered into the transcript
+	pub items: Vec<(&'static str, VRFTranscriptValue<'a>)>,
+}
+/// VRF signature data
+pub struct VRFSignature {
+	/// The VRFOutput serialized
+	pub output: VRFOutput,
+	/// The calculated VRFProof
+	pub proof: VRFProof,
+}
+
+/// Construct a `Transcript` object from data.
+///
+/// Returns `merlin::Transcript`
+pub fn make_transcript(data: VRFTranscriptData) -> Transcript {
+	let mut transcript = Transcript::new(data.label);
+	for (label, value) in data.items.into_iter() {
+		match value {
+			VRFTranscriptValue::Bytes(bytes) => {
+				transcript.append_message(label.as_bytes(), &bytes);
+			},
+			VRFTranscriptValue::U64(val) => {
+				transcript.append_u64(label.as_bytes(), val);
+			}
+		}
+	}
+	transcript
+}
+
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use crate::vrf::VRFTranscriptValue;
+	use rand::RngCore;
+	use rand_chacha::{
+		rand_core::SeedableRng,
+		ChaChaRng,
+	};
+
+	#[test]
+	fn transcript_creation_matches() {
+		let mut orig_transcript = Transcript::new(b"My label");
+		orig_transcript.append_u64(b"one", 1);
+		orig_transcript.append_message(b"two", "test".as_bytes());
+
+		let new_transcript = make_transcript(VRFTranscriptData {
+			label: b"My label",
+			items: vec![
+				("one", VRFTranscriptValue::U64(1)),
+				("two", VRFTranscriptValue::Bytes("test".as_bytes())),
+			],
+		});
+		let test = |t: Transcript| -> [u8; 16] {
+			let mut b = [0u8; 16];
+			t.build_rng()
+				.finalize(&mut ChaChaRng::from_seed([0u8;32]))
+				.fill_bytes(&mut b);
+			b
+		};
+		debug_assert!(test(orig_transcript) == test(new_transcript));
+	}
+}