Tracking Issue: Precompiles for Light Client

[tchataigner]

Currently, we leverage the zkvm or the decompress branch to leverage the pre-compiles in our light client implementation. I'm opening this issue to keep track of what is needed, what is available and what is to come.

Usage in Light Client

For the Light Client usage we are leveraging the bls crate on two main structures: PublicKey and Signature. PublicKey are structure defined over G1 while Signature are defined over G2. Those components have the following usage associated to them:

• PubllicKey
  • decompression: Conversion from a compressed form (slice of 48 bytes) to its decompressed one.
  • aggregate: Addition of G1 decompressed points. In the future, we might also need substraction for optimization purposes.
• Signature
  • decompression: Conversion from a compressed form (slice of 96 bytes) to its decompressed one.
• signature_verification : Verify an aggregated signature based on the aggregated public key, by leveraging the pairing mechanism.

What's to be integrated

After some exchange with @wwared here is what we believe should be integrated in this crate for our purposes:

Current status

Already on the branch

• [x] add, sub, mul of Fp
• [x] add, sub, mul of Fp2
• [x] Decompression of G1 in the unchecked endpoint
• [x] add and double for G1Affine (used in G1Affine::add_affine only for now)

To add

• [ ] add for G2Affine

To add in future work

• [ ] Fp2 sqrt (done, but not merged as a PR - might not get merged in favor of a G2 decompress precompile)
• [ ] Fp sqrt (same as above)
• [ ] Fp invert
• [ ] Fp2 invert
• [ ] double for G2Affine
• [ ] G2 decompress in the unchecked endpoint

[huitseeker]

Initial PR

Already on the branch

• [x] add, sub, mul of Fp
  • https://github.com/lurk-lab/bls12_381/blob/46673a9dbf0edfb9cb100af45a19fd79a40fa29b/src/fp.rs#L12
  • https://github.com/lurk-lab/bls12_381/blob/46673a9dbf0edfb9cb100af45a19fd79a40fa29b/src/fp.rs#L13
  • https://github.com/lurk-lab/bls12_381/blob/46673a9dbf0edfb9cb100af45a19fd79a40fa29b/src/fp.rs#L14
• [x] add, sub, mul of Fp2
  • https://github.com/lurk-lab/bls12_381/blob/46673a9dbf0edfb9cb100af45a19fd79a40fa29b/src/fp2.rs#L11
  • https://github.com/lurk-lab/bls12_381/blob/46673a9dbf0edfb9cb100af45a19fd79a40fa29b/src/fp2.rs#L12
  • https://github.com/lurk-lab/bls12_381/blob/46673a9dbf0edfb9cb100af45a19fd79a40fa29b/src/fp2.rs#L13
• [x] Decompression of G1 in the unchecked endpoint
  • https://github.com/lurk-lab/bls12_381/blob/zkvm/src/g1.rs#L21

[storojs72]

G2Affine addition has been landed to dev of wp1 (https://github.com/wormhole-foundation/wp1/pull/160)

cc @tchataigner