Change to use curve25519-voi's VRF

[Kynea0b]

Overview

The curve25519-voi ed25519 function is also referenced in cometbft/cometbft main or tendermint/tendermint master and is used for signing.
This library also implements VRF. Therefore, it is desirable to use this function for the VRF function.
This change removes libsodium, r2ishiguro, and all other unnecessary VRF libraries.

Ref:
https://github.com/oasisprotocol/curve25519-voi/blob/master/primitives/ed25519/extra/ecvrf/ecvrf.go

Advantages of using curve25519-voi

Briefly describe the advantages of using curve25519-voi's VRF.

• Compatibility with Golang standard ed25519 library (Signature verification is conditional on adjustment of preset values)
• It follows the cofactored verification equations required for signature verification in FIPS 186-5.
  Furthermore, by specifying VerifyOption, compatible with validation formulas according to FIPS 186-5, RFC 8032, and ZIP-215.
• VRF verification also guarantees security based on standards equivalent to the level defined by NIST for signature verification in FIPS 186-5. This code is it!
• Used for signature generation and verification on the Tendermint Core master branch or CometBFT main branch.
• Supports wasm.
• Assuming that calculations will be performed on VM, it reflects recent efforts to reduce calculation costs, and is actively being developed, and it is also quick to respond to vulnerabilities.
• Vulnerability support is faster.
• Easy to customize. This is because it is written in Golang and the implementation code is legible.

Background applied to master branch of Tendermint

Prior to this PR, for tendermint/tendermint master branch, hdevalence/ed25519consensus library was an implementation of ed25519 whose library was used for the signature scheme. This is also used in Ostracon. Tendermint seems to have applied curve25519-voi because of its improved batch processing algorithm, performance, and so on.

Refs

curve25519-voi is also refrenced here by cometBFT/cometBFT
https://github.com/cometbft/cometbft/blob/main/p2p/conn/secret_connection.go#L18

Closes: #620

[zemyblue]

I think this proposal is very great. The libsodium vrf was not modified in the very long times. And it has compile and linking issue because it is c++. So it is very good suggestion.

But migration should be considered since the vrf function is not compatible.
Let's check it.

[Yawning]

Oh neat more people using my library. Ok, I'm glad people think the code is legible.

But migration should be considered since the vrf function is not compatible.

It is the same IETF draft, my implementation just significantly post-dates when algorand did theirs, so it was after the spec changes broke compatibility. My implementation provides v7-v10 and v11+, while your libsodium fork implements v3.

The incompatibility comes from all the changes made to v7 of the draft.

[Kynea0b]

Thank you very much for your comment!!! The code is legible and the comments are polite and helpful. I really appreciate your explanation!!! @Yawning

[codecov]

Codecov Report

Merging #633 (903db19) into main (06e3b94) will decrease coverage by 0.17%.
The diff coverage is 77.77%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #633      +/-   ##
==========================================
- Coverage   66.21%   66.04%   -0.17%     
==========================================
  Files         277      275       -2     
  Lines       36992    36930      -62     
==========================================
- Hits        24494    24391     -103     
- Misses      10725    10772      +47     
+ Partials     1773     1767       -6     

Impacted Files	Coverage Δ
crypto/crypto.go	0.00% <ø> (ø)
crypto/secp256k1/secp256k1.go	69.56% <0.00%> (ø)
crypto/sr25519/pubkey.go	43.58% <0.00%> (ø)
state/execution.go	66.58% <ø> (ø)
statesync/stateprovider.go	31.20% <ø> (ø)
types/block.go	79.58% <ø> (ø)
types/validation.go	64.00% <ø> (ø)
crypto/ed25519/ed25519.go	51.38% <100.00%> (+6.26%)	⬆️

... and 17 files with indirect coverage changes

[ulbqb]

https://github.com/kokeshiM0chi/ostracon/blob/b900f94624e2d2157587e5ba9e5f088895f207d1/README.md?plain=1#L24
https://github.com/kokeshiM0chi/ostracon/blob/b900f94624e2d2157587e5ba9e5f088895f207d1/spec/core/data_structures.md?plain=1#L56

Please update these documents.

[Kynea0b]

Thank you!! I fixed as pointed out. PTAL @ulbqb

[ulbqb]

LGTM