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This repository has been archived. tBTC v1 is no longer actively maintained and has been superseded by tBTC v2. tBTC v2 code is available in the keep-network/tbtc-v2 repository.

tBTC is a trustlessly Bitcoin-backed ERC-20 token.

The goal of the project is to provide a stronger 2-way peg than federated sidechains like Liquid, expanding use cases possible via today’s Bitcoin network, while bringing superior money to other chains.

This repo contains the Solidity smart contracts and specification.

Getting started


tBTC contracts are currently published in the NPM Registry as the package @keep-network/tbtc. Packages have versions corresponding to their network:

  • -dev packages contain prerelease packages for the internal Keep testnet.

  • -ropsten packages contain prerelease packages for the Ropsten Ethereum testnet.

Note that only the latest package in a series is expected to reference contracts that have a backing set of signers.

To install the package:

$ npm install @keep-network/tbtc

NOTE: The tbtc package contains an indirect dependency to @summa-tx/relay-sol@2.0.2 package, which downloads one of its sub-dependencies via unathenticated git:// protocol. That protocol is no longer supported by GitHub. This means that in certain situations installation of the package may result in The unauthenticated git protocol on port 9418 is no longer supported error.
As a workaround, we advise changing Git configuration to use https:// protocol instead of git:// by executing:

git config --global url."https://".insteadOf git://


NOTE: tBTC contracts require solc v0.5.17 or higher. You may have to configure solc in your truffle-config.js.

Once installed, you can use the contracts in the library by importing them:

pragma solidity ^0.5.17;

import "@keep-network/tbtc/contracts/deposit/Deposit.sol";

contract MySystem {
    function checkTerm(address _depositAddress) external {
        uint256 remainingTerm = Deposit(_depositAddress).remainingTerm();


tBTC’s first 6-week audit was completed by ConsenSys Diligence on March 27, 2020, against fbb2018c41. They’ve published a detailed audit report and cryptographic review.

A Bitcoin-focused audit was conducted by security researcher Sergi Delgado from May 25 to May 31, 2020. You can review Sergi’s results on his site.

Trail of Bits conducted an audit of tBTC in June, 2020, and published a a summary of their results. @samczsun opened issues he discovered on the repo, all of which have been addressed.

A focused treatment of tBTC’s security model can be found here.

Please dislose any security issues you find or suspect to, or to @shadowfiend, @frdwrd, or @mhluongo via Keybase.


All contributions are welcome. To report bugs, please create an issue on this repository. To start a discussion, prefer Discord over GitHub issues.

Setup environment

You should have installed:


Clone and install dependencies:

git clone
cd tbtc/solidity
npm install

Deploy contracts:

truffle migrate --reset


Tests are written in JS using Mocha.

To run the test suite, execute truffle test.

To run specific tests, add .only to the contract block:

contract.only('TBTCToken', function(accounts) {


We use ESLint and Ethlint for linting code. To run:

npm run sol:lint:fix
npm run js:lint:fix


The documentation includes a project overview and rationale, as well as the on-chain specification. Docs should always be updated before or in tandem with code.


Docs are written in AsciiDoctor, with diagrams in Mermaid.


Install the dependencies via CLI:


gem install asciidoctor-pdf --pre
brew install poppler


cd docs

# Generate index.pdf
asciidoctor-pdf index.adoc


tBTC is released under the MIT License.