Generic Ring backend by davxy · Pull Request #27 · paritytech/verifiable

davxy · 2025-12-12T18:16:16Z

Major refactory:

RingSuiteExt: Enables easy integration of alternative implementations, such as those backed by polkadot-sdk hostcalls (see draft: Bandersnatch with EC hostcalls polkadot-sdk#10259).
RingCurveData: Centralizes pairing-curve-specific data. Bandersnatch uses BLS12-381, which can also be reused by other curves (i.e. bandersnatch alternatives hosted by BLS12-381), as well as by third-party Bandersnatch implementations (e.g., the polkadot-sdk hostcall-based version mentioned above).
RingProofParamsCache: Supports multiple strategies for caching pre-built parameters.
Bandersnatch concrete implementation (based on suite provided by ark-vrf)
Codebase reorganization

burdges · 2026-02-06T04:03:40Z

I wrote cleaner traits for EC VRFs and EC ring VRFs here :
https://github.com/paritytech/ring-vrf/blob/master/dleq_vrf/src/traits.rs

In particular, they handle multiple input-output pairs better, which many ring VRF protocols require.

davxy · 2026-02-06T07:38:02Z

I wrote cleaner traits for EC VRFs and EC ring VRFs here : https://github.com/paritytech/ring-vrf/blob/master/dleq_vrf/src/traits.rs

In particular, they handle multiple input-output pairs better, which many ring VRF protocols require.

Perhaps this is not related to this PR :-)

In this PR, we make the Verifiable trait generic over the specific Bandersnatch implementation. This enables the use of the implementation backed by the host calls we are currently working on.

ggwpez

Is it rebased? GH wont show me

ggwpez · 2026-02-13T16:18:04Z

src/ring/bandersnatch.rs

+use crate::ring::{Bls12_381RingData, RingSuiteExt, RingVrfVerifiable};
+use ark_vrf::suites::bandersnatch::{BandersnatchSha512Ell2, RingProofParams};
+
+#[cfg(any(feature = "std", feature = "no-std-prover"))]


Suggested change

#[cfg(any(feature = "std", feature = "no-std-prover"))]

#[cfg(feature = "prover")]

And then enable that by feature std.

Makes sense

ggwpez · 2026-02-13T16:23:12Z

src/ring/bandersnatch.rs

+
+/// Tests that require the `builder-params` feature.
+#[cfg(all(test, feature = "builder-params"))]
+mod builder_tests {


Could put into bandersnatch_tests.rs file or so

In that case, I would also be inclined to move the entire set of Bandersnatch-related tests (the mod test above) into that file. However, why move the tests to a separate file? The current module does not appear particularly cluttered.

src/ring/mod.rs

ggwpez · 2026-02-13T16:30:06Z

src/ring/mod.rs

+	type Handle = alloc::boxed::Box<ark_vrf::ring::RingProofParams<S>>;
+
+	fn get(domain_size: RingDomainSize) -> Self::Handle {
+		alloc::boxed::Box::new(make_ring_prover_params::<S>(domain_size))


The decoding is not cached with a Once cell anymore?

I introduced RingProofParamsCache as an associated type of the RingSuiteExt trait.

We provide two concrete implementations of this trait:

() : This is the implementation you observed. It performs no parameter caching. Perhaps I can define a NullCache type, which may be more explicit.

BandersnatchParamsCache : Defined in the bandersnatch.rs module. It implements caching similarly to the previous approach, except that it uses the spin crate for both std and no_std environments.

This abstraction enables users to define a custom caching strategy if the default implementations provided by the crate do not meet their requirements

Okay makes sense, thanks. I must have missed it in the review.

I support calling it NullCache or NoCache or anything like that.

davxy · 2026-02-13T21:18:53Z

Is it rebased? GH wont show me

I force-pushed 🫣
Effectively, I just reused the branch name, as the current code is very different from the previous PR.

src/ring/mod.rs

davxy · 2026-02-18T17:58:20Z

@ggwpez @georgepisaltu As I'd like to move forward, If there are no objections by tomorrow, I will proceed with merging this.

georgepisaltu

Sorry for the late review. Just a couple of comments, but looks good.

georgepisaltu · 2026-02-18T23:00:11Z

src/ring/mod.rs

+	type Handle = alloc::boxed::Box<ark_vrf::ring::RingProofParams<S>>;
+
+	fn get(domain_size: RingDomainSize) -> Self::Handle {
+		alloc::boxed::Box::new(make_ring_prover_params::<S>(domain_size))


I support calling it NullCache or NoCache or anything like that.

georgepisaltu · 2026-02-18T23:02:42Z

src/ring/mod.rs

+}
+
+pub trait EncodedTypesBounds:
+	Clone + Eq + FullCodec + core::fmt::Debug + TypeInfo + MaxEncodedLen + AsRef<[u8]> + AsMut<[u8]>


Can we also add DecodeWithMemTracking since this will be used in the runtime? It's not covered by FullCodec.

georgepisaltu · 2026-02-18T23:18:44Z

src/ring/mod.rs

+
+#[inline(always)]
+fn make_alias<S: RingSuiteExt>(output: &ark_vrf::Output<S>) -> Alias {
+	Alias::try_from(&output.hash()[..32]).expect("Suite hash should be at least 32 bytes")


Technically this will panic when you try to access the slice like &output.hash()[..32] before we get to the try_from. There's not much of a difference even if we write this differently and guard against it, but maybe we can statically check with a test or something that the hash output on the ark_vrf::Output<S> we use is at least 32 bytes?

…ard compat

davxy added 3 commits February 5, 2026 11:51

Define RingCurveData trait and BLS12-381 impl

03af42d

impl_scale for generic types

ec14cd8

Generic RingVerifiable

27129a6

davxy force-pushed the davxy/generic-bandersnatch branch from e660c7a to 27129a6 Compare February 5, 2026 12:07

davxy added 2 commits February 5, 2026 13:17

Some refactory

7b5789d

Everything should be generic now

03eef58

davxy changed the title ~~Generic Bandersnatch suite~~ Generic Ring backend Feb 5, 2026

davxy added 11 commits February 5, 2026 16:00

Remove stuff

86ec6af

Fix tests

8179b9e

Simplify

7d0a646

Further simplification

bf97b68

RingSuiteExt

3f60697

ParamsCache type

955a02c

Everything should be generic now

99cc119

Move tests

bb16d3b

More re-org

10c286b

Codec assumptions check

2374852

One more test

07cda9e

davxy marked this pull request as ready for review February 5, 2026 17:58

davxy requested review from Zebedeusz, georgepisaltu and ggwpez February 5, 2026 18:00

Fix binary files path

cc381ea

ggwpez reviewed Feb 13, 2026

View reviewed changes

davxy requested a review from ggwpez February 13, 2026 21:19

ggwpez reviewed Feb 16, 2026

View reviewed changes

src/ring/mod.rs Outdated Show resolved Hide resolved

davxy added 2 commits February 16, 2026 13:20

Merge branch 'main' into davxy/generic-bandersnatch

82b7c1e

Introduce 'prover' feature

eb2d633

davxy requested a review from ggwpez February 17, 2026 09:07

ggwpez approved these changes Feb 18, 2026

View reviewed changes

georgepisaltu approved these changes Feb 18, 2026

View reviewed changes

davxy added 5 commits February 19, 2026 10:17

NullCache alias

640519c

DecodeWithMemTracking as additional bound for EncodedTypesBounds

76ae50a

Don't panic if hash length is <32

827abf7

Renaming

c206c6e

Move VRF input domain separator to RingSuiteExt trait to ensure backw…

4037a8e

…ard compat

davxy merged commit a304016 into main Feb 19, 2026
1 check passed

davxy deleted the davxy/generic-bandersnatch branch February 19, 2026 11:03

	#[cfg(any(feature = "std", feature = "no-std-prover"))]
	#[cfg(feature = "prover")]

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davxy commented Dec 12, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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davxy commented Feb 13, 2026

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davxy commented Dec 12, 2025 •

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