RiB Newsletter #24 - Bridges

June 02, 2021

Welcome to the #24 edition of Rust in Blockchain, the chillest newsletter about the chillest tech. Previous: #23

This month we’re interested in cross-chain bridges. With Ethereum at capacity recently, other blockchain projects are eyeing the window of opportunity between now and a functional Ethereum 2 to siphon away some of that chain’s activity. So there seems to be a rush to get bridges built between Ethereum and every other chain, not to mention between pairs of non-Ethereum chains. It looks like we are well on our way to an internetwork of blockchains, so now is a good time to do a survey of bridges to Rust chains.

These bridges mostly support moving fungible tokens today, and some plan to support NFTs; contrasting with general cross-chain communications protocols like IBC and XCMP.

While the details differ between bridges and chains, it seems that many of these bridges are their own distributed networks, with similar behavior:

They operate a network of validators.
They maintain custodial contracts on each chain.
Multisig cryptography is used by the validators to agree on pairs of cross-chain transactions.
The bridge network may offer cryptoeconomic incentives for node operators.
Watchdog nodes may monitor the network for misbehavior.
Some of these networks are themselves blockchains, but many are not.

For a more informed description of bridges see this recent blog post from Patrick McCorry.

Some of those in the Rust world include

Secret · Ethereum Bridge. Between Secret Network and Ethereum. Mainnet.
Secret · Monero Bridge. Between Secret Network and Monero. Testnet.
- This is particularly interesting because there are relatively few on/off-ramps for privacy-preserving Monero, and this is a bridge to another privacy chain.
Secret · Binance Smart Chain Bridge. Between Secret Network and Binance Smart Chain. Testnet.
Secret · Plasm Bridge. Between Secret Network and Plasm Network. Not live.
- This one will link Secret Network to the world of Polkadot parachains, and to to the world of Cosmos/IBC-based chains, as Plasm is a Substrate chain that is intended to connect to both.
Near · Rainbow Bridge. Between Near and Ethereum. Mainnet.
Solana · Wormhole. Between Solana and Ethereum. Mainnet.
Nervos · Force-Bridge. Between Nervos CKB and Ethereum. Testnet.
Polkadot · PolkaBTC. Between Polkadot and Bitcoin.
Polkadot · Snowbridge. Between Polkadot and Ethereum. Not live.
Polkadot · Darwinia. Between Polkadot and Ethereum.
Polkadot · ChainBridge. Between Polkadot and Ethereum.
Polkadot · Bifrost. Between Polkadot and EOS.

Polkadot’s family of bridges is described here.

Thanks

Thanks to contributors: A Pruden, Júlio Santos, Max Wegman, naternater, Tor Bair, Brian Anderson, and Aimee Zhu. Thank you for your help!

RiB needs help to keep up with Rust blockchain projects. If you follow a particular project, or otherwise find information that is beneficial to the Rust & blockchain community, please contribute to the next issue by submitting a PR to the #25 draft.

Project Spotlight

Each month we like to shine a light on a notable Rust blockchain project. This month that project is…

TDN (and Chamomile).

Trusted Distributed Network is a framework for building distributed applications, with support for p2p communications, multiple cross-communicating blockchains, multiple layers of blockchains, and multiple account models. It is built on a new p2p library, Chamomile.

TDN appears to be somewhat comparable to Substrate, and Chamomile to libp2p.

Chamomile adds to the choices available to Rust developers for p2p networking, which already include rust-libp2p, and tentacle.

These projects are authored by @sunhauchuang who also created Awesome Rust Blockchain.

Interesting Things

News

Blog Posts

Power of Tau, or How I Learned to Stop Worrying and Love the Setup

Papers

Projects

snarkVM. A Virtual Machine for Zero-Knowledge Executions.
Polkadex. An Orderbook-based Decentralized Exchange using the Substrate Blockchain Framework.