Welcome to Bitfinity: A Next-Generation BTC Layer 2 Solution

Bitfinity is a blazingly-fast (1000 TPS+), next-generation EVM, serving as a Layer Two for Bitcoin and other Bitcoin on-chain assets. With Bitfinity, you will be able to deploy smart-contracts for Bitcoin, Ordinals, BRC-20 – all written in Solidity. Bitfinity is built on the Internet Computer.

Layer 2 solutions are ubiquitous in the Ethereum world, and primarily rely on zero-knowledge cryptography or optimistic rollups to create secure bridges between the base layer-1 chain and the layer-2.

Bitfinity instead uses a threshold cryptographic scheme, called Chain-Key, to create a secure decentralised bridge between Bitfinity and the Bitcoin blockchain. Chain-key is unique, in that no single node ever has access to the threshold key, the threshold key shares are regenerated on a periodic basis every 11 minutes through “moon-math”.

Getting Started
To get started, follow the guide in the getting-started section:

connect your wallet to Metamask
mint test-net tokens
bridge your cross-chain Bitcoin assets to Bitfinity.
Currently, Bitcoin is supported in our wallet, but trustless bridges for BRC-20s Bitcoin and the EVM are launching soon.

To request some ETH on Bitfinity Testnet, go to Bitfinity Testnet Faucet

Still have questions? Check out our answers to frequently asked questions (FAQs).

Information on the background technology
Bitfinity leverages a threshold signature scheme to custody Bitcoin. Detailed information about the threshold ECDSA protocol, its implementation challenges, and potential use cases are outlined in these articles. The protocol for secured and decentralised bridging of cross-chain assets has been built by researchers from the Internet Computer:

Chain-key Summary
Chain-Key technical Overview
Original Forum Post
Example Code for tECDSA
Audits on tECDSA
Additional Info
Running Bitcoin nodes on-chain. This section covers the discussions and developments related to running Bitcoin nodes on another blockhain, to realise trust-minimized bridging. This integration process, which started in 2021, involves syncing Bitcoin nodes on the Internet Computer for use on Bitfinity.

Discussion on Direct Integration with Bitcoin
Forum Post on Chain-Key Bitcoin
Sample Code for Interacting with Bitcoin on IC
Overview of Bitcoin Integration with Internet Computer
Technical Overview of Bitcoin Integration with Internet Computer
Ordinals Marketplace on the IC Utilizing These Primitives
Connectivity with the web: Decentralised infrastructure to make asynchronous calls to the web, removing the need for traditional oracles. Outcalls Wiki Outcalls Technical Overview

In addition to the work on threshold signatures, there is an ongoing effort to develop the threshold signature scheme for Schnorr. Threshold Signatures for Schnorr would enable Bitfinity to issue Taproot transactions on Bitcoin.

https://eprint.iacr.org/2023/1019.pdf https://eprint.iacr.org/2023/1175.pdf