Add Ethereum-compatible aliases for BLS12-381 #4186

Jim8y · 2025-09-22T04:27:21Z

This is requested and needed by NeoX.

Description

Adds Ethereum-compatible aliases for the BLS12-381 native contract methods (bls12_*) while
retaining the existing bls12381* surface. This keeps Neo and EVM tooling interoperable without
schema changes. Updated tests cover both naming schemes, and the expected genesis manifest now
includes the new ABI entries.

Fixes # (issue)

Type of change

New feature (non-breaking change which adds functionality)

How Has This Been Tested?

dotnet test tests/Neo.UnitTests/Neo.UnitTests.csproj --filter CryptoLib

Test Configuration:

.NET SDK 9.0.301
Default protocol settings via test harness

Checklist:

My code follows the style guidelines of this project
I have performed a self-review of my code
I have commented my code, particularly in hard-to-understand areas
I have made corresponding changes to the documentation
My changes generate no new warnings
I have added tests that prove my fix is effective or that my feature works
New and existing unit tests pass locally with my changes
Any dependent changes have been merged and published in downstream modules

cschuchardt88 · 2025-09-22T19:50:48Z

src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs

            };
        }

+        [ContractMethod(Hardfork.HF_Gorgon, CpuFee = 1 << 19, Name = "bls12_g1add")]


Shouldn't it be HF_Faun

Yes, it should be Faun

vncoelho

Looks good, it can be in the next release

roman-khimov

What's preventing contracts from using the already existing names?

AnnaShaleva · 2025-09-23T09:36:46Z

src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs


+        [ContractMethod(Hardfork.HF_Gorgon, CpuFee = 1 << 19, Name = "bls12_g1add")]
+        public static InteropInterface Bls12G1Add(InteropInterface x, InteropInterface y)
+            => Bls12381Add(x, y);


Adds Ethereum-compatible aliases

CryptoLib calls won't be compatible with Ethereum anyway, so I don't think this PR can be accepted. It adds an ambiguity to the CryptoLib interface.

BTW, the same thing (if we really care about specific names which is questionable to me since it's about N3 contracts, they're different from EVM/Solidity contracts anyway) can be provided by devpack without contract modifications (and code/manifest bloat).

shargon

It only change the name?

Wi1l-B0t

It seems to be just for compatibility.

Jim8y · 2025-09-26T01:13:55Z

What's preventing contracts from using the already existing names?

hi roman @roman-khimov , this is a requested change for neox, i am not sure the detail, but i guess its related to eip standards, you or anna should know it better than me.

roman-khimov

Aliases are not needed. We need to add compatibility with https://eips.ethereum.org/EIPS/eip-2537 and the only thing that can be incompatible now is bls12381MultiExp. So there is some functional extension we need here rather than aliases.

txhsl · 2025-09-26T07:11:27Z

We need to add compatibility with https://eips.ethereum.org/EIPS/eip-2537 and the only thing that can be incompatible now is bls12381MultiExp.

Yes, the EIP-2537 has been updated several times since Feb 2024, but now it gets finalized. The history can be referred https://github.com/ethereum/EIPs/commits/master/EIPS/eip-2537.md.

erikzhang · 2025-10-20T02:19:16Z

@neo-project/ngd-shanghai Need testing.

roman-khimov · 2025-10-20T07:17:36Z

src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs

+        /// </summary>
+        /// <param name="pairs">Array of [point, scalar] pairs.</param>
+        /// <returns>The accumulated point.</returns>
+        [ContractMethod(Hardfork.HF_Gorgon, CpuFee = 1 << 23)]


txhsl · 2025-10-20T09:32:11Z

src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs

+                        {
+                            var scalar = ParseScalar(pair[1]);
+                            if (!scalar.IsZero)
+                                g1Accumulator += new G1Projective(g1Affine) * scalar;


We need to make sure that subgroup check is executed before any multiplication operation. This was fixed in Ethereum through ethereum/EIPs#8456.

Briefly speaking, we need:

"IsOnCurve" check after G1 point decoding and G2 point decoding, e.g. https://github.com/ethereum/go-ethereum/blob/v1.16.5/core/vm/contracts.go#L1212;

"IsInSubGroup" check before multiply and pairing computation, e.g. https://github.com/ethereum/go-ethereum/blob/v1.16.5/core/vm/contracts.go#L1005 and https://github.com/ethereum/go-ethereum/blob/v1.16.5/core/vm/contracts.go#L1173.

About the detailed implementation of these checks, please ref https://github.com/Consensys/gnark-crypto/blob/v0.19.0/ecc/bls12-381/g1.go#L193-L218 and https://github.com/Consensys/gnark-crypto/blob/v0.19.0/ecc/bls12-381/g2.go#L200-L223.

src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs

shargon · 2025-10-20T09:36:31Z

src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs

+        /// <param name="pairs">Array of [point, scalar] pairs.</param>
+        /// <returns>The accumulated point.</returns>
+        [ContractMethod(Hardfork.HF_Faun, CpuFee = 1 << 23)]
+        public static InteropInterface Bls12381MultiExp(Array pairs)


Maybe we need to check the length, a max is required or it could deny the service with 1024 pairs

cschuchardt88 · 2025-10-23T08:21:34Z

the right way to execute a test by filters is

 dotnet test tests/Neo.UnitTests/Neo.UnitTests.csproj -- --filter CryptoLib

Jim8y added the Waiting for Review label Sep 22, 2025

Add Ethereum-compatible aliases for BLS12-381

1a443fe

Jim8y force-pushed the feature/bls12-eth-aliases branch from a157ce3 to 1a443fe Compare September 22, 2025 04:32

Format codebase

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cschuchardt88 reviewed Sep 22, 2025

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vncoelho reviewed Sep 22, 2025

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roman-khimov reviewed Sep 23, 2025

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AnnaShaleva reviewed Sep 23, 2025

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shargon reviewed Sep 24, 2025

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Merge branch 'dev' into feature/bls12-eth-aliases

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Wi1l-B0t previously approved these changes Sep 26, 2025

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roman-khimov requested changes Sep 26, 2025

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Jim8y added 2 commits October 14, 2025 19:13

Merge branch 'dev' into feature/bls12-eth-aliases

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Implement BLS12-381 multi exponentiation

1f82a9b

Jim8y dismissed Wi1l-B0t’s stale review via 1f82a9b October 17, 2025 02:26

Merge branch 'dev' into feature/bls12-eth-aliases

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roman-khimov reviewed Oct 20, 2025

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roman-khimov mentioned this pull request Oct 20, 2025

BLS12-381 multi exponentiation nspcc-dev/neo-go#4041

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txhsl reviewed Oct 20, 2025

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Merge branch 'dev' into feature/bls12-eth-aliases

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shargon reviewed Oct 20, 2025

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src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs Outdated Show resolved Hide resolved

Update src/Neo/SmartContract/Native/CryptoLib.BLS12_381.cs

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shargon reviewed Oct 20, 2025

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erikzhang mentioned this pull request Oct 22, 2025

Dev meeting - 10-23-2025 #4236

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Jim8y added 2 commits October 23, 2025 09:58

Merge branch 'dev' into feature/bls12-eth-aliases

b6fb04b

Harden BLS12-381 multi exponentiation

5f4dbe5

cschuchardt88 and others added 2 commits October 22, 2025 23:21

Merge branch 'dev' into feature/bls12-eth-aliases

2e8378c

Merge branch 'dev' into feature/bls12-eth-aliases

434c62e

Add Ethereum-compatible aliases for BLS12-381 #4186

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