Summary

Different Ed25519 implementations verify signatures in subtly different ways. This will pose a problem for future implementations of Tendermint which may use different Ed25519 libraries. ZIP 215, from the Zcash Foundation team, “settles the situation by explicitly defining the Ed25519 validity criteria and changing them to be compatible with batch validation.”

Proposal

We should adopt ZIP 215, for more consistent signature verification for all Tendermint implementations.

Next steps:

• Merge RFC in tendermint/spec: RFC: adopt zip 215 spec#144
• Migrate tendermint/tendermint to use https://github.com/hdevalence/ed25519consensus
• Update related documentation

Note that this should be treated as a breaking change.

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