RFC: adopt zip 215

rfc/003-ed25519-verification.md

@@ -0,0 +1,56 @@
+# RFC 003: Ed25519 Verification
+
+## Changelog
+
+- August 21, 2020: initialized
+
+## Author(s)
+
+- Marko (@marbar3778)
+
+## Context
+
+Ed25519 keys are the only supported key types for Tendermint validators currently. Tendermint-Go wraps the ed25519 key implementation from the go standard library. As more clients are implemented to communicate with the canonical Tendermint implementation (Tendermint-Go) different implementations of ed25519 will be used. Due to [RFC 8032](https://www.rfc-editor.org/rfc/rfc8032.html) not guaranteeing implementation compatibility, Tendermint clients must to come to an agreement of how to guarantee implementation compatibility. [Zcash](https://z.cash/) has multiple implementations of their client and have identified this as a problem as well. The team at Zcash has made a proposal to address this issue, [Zcash improvement proposal 215](https://zips.z.cash/zip-0215).
+
+## Proposal
+
+- Tendermint-Go would adopt [hdevalence/ed25519consensus](https://github.com/hdevalence/ed25519consensus).
+    - This library is implements `ed25519.Verify()` in accordance to zip-215. Tendermint-go will continue to use `crypto/ed25519` for signing and key generation.
+
+- Tendermint-rs would adopt [ed25519-zebra](https://github.com/ZcashFoundation/ed25519-zebra)
+    - related [issue](https://github.com/informalsystems/tendermint-rs/issues/355)
+
+Signature verification is one of the major bottlenecks of Tendermint-go, batch verification can not be used unless it has the same consensus rules, ZIP 215 makes verification safe in consensus critical areas.
+
+This change constitutes a breaking changes, therefore must be done in a major release. No changes to validator keys or operations will be needed for this change to be enabled.
+
+This change has no impact on signature aggregation. To enable this signature aggregation Tendermint will have to use a different curve i.e [BLS](https://en.wikipedia.org/wiki/Boneh%E2%80%93Lynn%E2%80%93Shacham). Secondly, this change will enable safe batch verification for the Tendermint-Go client. Batch verification for the rust client is already supported in the library being used.
+
+As part of the acceptance of this proposal it would be best to contract or discuss with a third party the process of conducting a security review of the go library.
+
+## Status
+
+Proposed
+
+## Consequences
+
+### Positive
+
+- Consistent signature verification across implementations
+- Enable safe batch verification
+
+### Negative
+
+#### Tendermint-Go
+
+- Third_party dependency
+    - library has not gone through a security review.
+    - unclear maintenance schedule
+- Fragmentation of the ed25519 key for the go implementation, verification is done using a third party library while the rest
+  uses the go standard library
+
+### Neutral
+
+## References
+
+[It’s 255:19AM. Do you know what your validation criteria are?](https://hdevalence.ca/blog/2020-10-04-its-25519am)

rfc/README.md

@@ -23,3 +23,5 @@ Some RFC's will be presented at a Tendermint Dev Session. If you are an outside
 ## Table of Contents
 
 [001-block-retention](./001-block-retention.md)
+[002-nonzero-genesis](./002-nonzero-genesis.md)
+[003-ed25519-verification](./003-ed25519-verification.md)