Implement MapToCurve for Parameters

[drskalman]

In order for your hash to be usable and testable in Arkwork, you need to implement this trait for BLS12-381 and BLS12-377:

https://github.com/arkworks-rs/algebra/blob/master/ec/src/hashing/map_to_curve_hasher.rs#L6

similar to

https://github.com/arkworks-rs/algebra/blob/master/ec/src/hashing/curve_maps/swu/mod.rs#L39

This should quite similar to what you have already have in your code.

[zhenfeizhang]

This is currently impossible, and I suggest not to enable this at the current stage.

• the current version of IndifferentiableHashing is fully compatible with arkworks 0.3.0 release
• arkworks 0.4.0 are not ready, and cannot be used at the current stage. you may try to build

  ark-bls12-381 = { git = "https://github.com/arkworks-rs/curves/", features = [ "curve" ], default-features = false, rev = "6d94362894f30c90de7eb2d310223dc2b0712bd7" }

  and you will see the compiler complains about ark-bls12-381 itself.

Anyway I have create a branch https://github.com/zhenfeizhang/indifferentiable-hashing/tree/prepare-for-0.4.0 https://github.com/zhenfeizhang/indifferentiable-hashing/blob/prepare-for-0.4.0/src/lib.rs#L26 and you can see that implementing the trait itself is kind of trivial. The main blocker right now is arkworks itself.

[drskalman]

Please use "https://github.com/w3f/arkworks-curves/" instead.

[zhenfeizhang]

same thing

error: cannot determine resolution for the macro `MontFp`
  --> /home/z/.cargo/git/checkouts/arkworks-curves-4155937fa1910b8a/efefa20/bls12_377/src/fields/fq12.rs:50:13
   |
50 |             MontFp!("165715080792691229252027773188420350858440463845631411558924158284924566418821255823372982649037525009328560463824"),

[dependencies]
ark-ff = { version = "^0.3.0", default-features = false }
ark-ec = { version = "^0.3.0", default-features = false }
ark-std = { version = "^0.3.0", default-features = false }
ark-bls12-381 = { git = "https://github.com/w3f/arkworks-curves/",  default-features = false, features = [ "curve" ] }
ark-bls12-377 = { git = "https://github.com/w3f/arkworks-curves/",  default-features = false, features = [ "curve" ] }
ark-serialize = { version = "^0.3.0", default-features = false }

[zhenfeizhang]

and TBH at the time this library is written the latest released version is 0.3.0. Keep updating this library for future unreleased version of Arkworks is not in the deliverables.

The deliverable is a rust implementation

**Deliverables**
| Number | Deliverable | Link | Notes |
| ------------- | ------------- | ------------- |------------- |
| 0a. | License | [LICENSE](https://github.com/zhenfeizhang/indifferentiable-hashing/blob/master/LICENSE) | MIT |
| 0b. | Documentation |  | Inline documentation |
| 0c. | Testing Guide | https://github.com/zhenfeizhang/indifferentiable-hashing#testing | You may need [SageMath](https://www.sagemath.org/) to validate test vectors
| 0e. | Article | Section 1.1 of my new article https://eprint.iacr.org/2021/1082 | ... |
| 1. | Rust non-constant-time implementation | https://github.com/zhenfeizhang/indifferentiable-hashing | ... |

[Pratyush]

I'm happy to help with merging this upstream, if that makes sense

[drskalman]

• There is 0.4.0-alpha release is out and it compiles for bls12-377 and bls12-381.
• https://github.com/w3f/arkworks-curves/ has a working implementation of WB hash2curve and it has a pull request to upstream.
• Using Arkworks framework is expilicit in the application.
• If @dishport is concern for their hash function to be used and evaluated by the community and shown to be faster than WB then taking @Pratyush 's offer and making it available in Arkworks is the best route for that.

[drskalman]

hash to curve has been merged in arkworks-rs/algebra master as well. So you don't need any patch, just use arkworks 0.4.0.

[zhenfeizhang]

Thanks for the updates. So this repo remains as a self-contained implementation of ind hashes.

For integrated version with arkworks 0.4.0, please see

https://github.com/zhenfeizhang/algebra/pull/1 https://github.com/zhenfeizhang/curves/pull/1

[drskalman]

Very cool!