CIP 20 - Extensible Hash Precompile - Discussions

[prestwich]

Migrating my comments from the forum:

The goal is to provide access to some common cryptographic hash functions. We do that by adding them all to a single precompile. Right now the precompile supports common SHA3 variants (SHA3-256, SHA3-512, and Keccak-512), as well as blake2s

Link to CIP

Deployment Checklist

• Specification
• Implementation
  • celo-blockchain #1249
• Testing
  • Unit tests
  • Fuzzing w/ smash
  • Benching & Gas assignment
  • gas calculation tests
• Pre-deploy
  • Precompile Address assignment in Donut block
• Verification
  • Run the test vectors via eth_call RPC

[prestwich]

I ran benchmarks on our blake2s implementation against golang stdlib sha256:

BenchmarkHash64-8        6719373               178 ns/op         360.12 MB/s
BenchmarkHash128-8       3734914               322 ns/op         397.93 MB/s
BenchmarkHash1K-8         542121              2209 ns/op         463.63 MB/s
BenchmarkSha64-8         3136120               382 ns/op         167.56 MB/s
BenchmarkSha128-8        2240745               546 ns/op         234.63 MB/s
BenchmarkSha1K-8          418257              2858 ns/op         358.33 MB/s

The blake2s implementation outperforms sha2 in all cases. I'd suggest setting the gas costs equal to sha2 for now

[weijiekoh]

Is it possible for this precompile to, in the future, enable support for snark-friendly hash functions like Poseidon?