Tendermint X

Implementation of zero-knowledge proof circuits for Tendermint.

Overview

Tendermint X's core contract is TendermintX, which stores the headers of Tendermint blocks. Users can query a TendermintX contract for the header of a specific block height, or for the latest header.

There are two entrypoints to a TendermintX contract, step and skip.

skip

skip is used to jump from the current header to a non-consecutive header.

For example, let's say block N has already been proven in the light client, and we want to prove block N+10. We can skip from block N to block N+10 if 1) the validators who have signed the commit for block N+10 comprise > 1/3 of the voting power on block N and 2) validators comprimising > 2/3 of the voting power on block N+10 have signed the commit for block N+10.

The methodology for doing so is described in the section 6 of A Tendermint Light Client.

step

step is used to sequentially verify the next header after the current header.

This is rarely used, as step will only be invoked when the validator set changes by more than 2/3 in a single block.

Deployment

The circuits are currently available on Succinct X here.

There are currently Tendermint X light clients tracking the following networks on Goerli:

• dYdX
• Osmosis
• Celestia Mainnet

Benchmarks

Chain	# of Validators	plonky2 Proving Time	End to End Proving Time
dYdX	60	2 mins	5 mins
Celestia	100	5 mins	8 mins
Osmosis	150	9 mins	12 mins

Integrate Tendermint X

1. Request a Succinct Platform API Key: https://alpha.succinct.xyz/partner

2. Fork this repository: https://github.com/succinctlabs/tendermintx

3. Update the VALIDATOR_SET_SIZE_MAX to match that of your Tendermint chain in circuits/consts.rs (ex. 150 for Osmosis, 60 for dYdX). Push the changes to your fork.

4. Go to the Succinct Platform.

5. Sign up for an account on the platform.

6. Create a new project on the Succinct Platform by importing your fork of tendermintx.

7. In your project on the platform, go to Releases. Create two new releases, one for step and one for skip. Use the main branch and set the entrypoint accordingly.

8. In your project on the platform, go to Settings. Set TENDERMINT_RPC_URL in Environment Variables. This should be a valid full node RPC for your Tendermint chain.

9. Once the releases are completed building, go to Deployments to deploy the verifiers for step and skip.

10. Open the code for your fork of TendermintX again.

11. Update contracts/.env accoridng to contracts/.env.example. Note: The genesis parameters are typically sourced from a recent header from your Tendermint chain.

12. Deploy your TendermintX contract and initialize it with your function ID & genesis parameters using the commands below.

forge install

forge script script/Deploy.s.sol --rpc-url $ETHEREUM_RPC_URL --private-key $PRIVATE_KEY --etherscan-api-key $ETHERSCAN_API_KEY --verify TendermintX --broadcast

13. Update .env according to .env.example.

14. Run TendermintX script to update the light client continuously (currently set to update once every 4 hours).

cargo run --bin tendermintx --release

14. Now, go the platform to monitor the status of your proofs. Generating a Tendermint LC proof takes anywhere from 4-15 minutes, depending on your validator set size.

Misc

Tendermint RPC's

To find a list of RPC's for most Tendermint chains, check out this page created by @deving_zone.

Block Protocol Version

Tendermint X is configured to work with CometBFT block protocol version 11. If this changes in the future, the Tendermint X circuits might need to be updated.

Audit

Informal Audit

• Tendermint X has been audited by Informal Systems. The audit report can be found here.