Cosmos fork detection and IBC fork detection

Status

This is a work in progress. This directory captures the ongoing work and discussion on fork detection both in the context of a Cosmos light node and in the context of IBC. It contains the following files

detection.md

a draft of the light node fork detection including “proof of fork” definition, that is, the data structure to submit evidence to full nodes.

discussions.md

A collection of ideas and intuitions from recent discussions

• the outcome of recent discussion
• a sketch of the light client supervisor to provide the context in which fork detection happens
• a discussion about lightstore semantics

req-ibc-detection.md

• a collection of requirements for fork detection in the IBC context. In particular it contains a section “Required Changes in ICS 007” with necessary updates to ICS 007 to support Cosmos fork detection

draft-functions.md

In order to address the collected requirements, we started to sketch some functions that we will need in the future when we specify in more detail the

• fork detections
• proof of fork generation
• proof of fork verification

on the following components.

• IBC on-chain components
• Relayer

TODOs

We decided to merge the files while there are still open points to address to record the current state an move forward. In particular, the following points need to be addressed:

• https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466504876

• https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466493900

• https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466489045

• https://github.com/informalsystems/tendermint-rs/pull/479#discussion_r466491471

Most likely we will write a specification on the light client supervisor along the outcomes of

• https://github.com/informalsystems/tendermint-rs/pull/509

that also addresses initialization

• https://github.com/tendermint/spec/issues/131