tBTC, the open-source project that allows people to use Bitcoin safely in Ethereum DeFi apps, is live and ready to be used. A project of Keep, Summa and the Cross-Chain Group, tBTC lets people exchange BTC for TBTC, an ERC-20 token that can be used on DeFi platforms, at a rate of 1:1.
Each TBTC token is fully backed and matched by at least 1 BTC held in reserve. tBTC is trustless, using a random beacon to select “signers” who have responsibility for the deposited BTC. People can convert TBTC to BTC, and vice-versa with no intermediary needed to sign off. There are three steps for people to mint TBTC on tbtc.network and track their Bitcoin.
The project uses threshold ECDSA, which is audited and in use on wallets and exchanges. Via Nexus Mutual, there are protections of funds covering issues in Solidity on Ethereum.
tBTC has undergone three audits. tBTC concluded its first security audit, by ConsenSys, in March. In June, a second audit by Trail of Bits was concluded and in August there was a Bitcoin audit conducted by Sergei Delgado.
tBTC’s launch is in accordance with a “release candidate” model. Release candidates progress from 0, to 1, to 2, onward until a candidate is deemed final and upgraded to the stable release.
The alpha launch of tBTC -- known as rc.0 -- went live on mainnet in May after a public audit from ConsenSys Diligence. An issue was discovered and there was a pause in accepting new funds. rc.1 resolves the issue, and is live as of September.
The current live dApp built atop rc.1 will remain in alpha for a period of several weeks, during which there will be a graduated supply cap. Then, it will have a beta release cut.
rc.1 has a hard cap on the TBTC supply, starting at 100 BTC in the first week. Each week, the contracts will loosen the deposit restriction based on a pre-committed schedule.
For the first 48 hours after going live, there is a low supply cap to allow for low-risk testing. The supply cap will then increase to 100 TBTC for the remainder of the first week, then go up to 250 TBTC a week later.
The supply cap will increase by 250 TBTC every week until it reaches 1000 TBTC. After that, the increase will be by 500 TBTC every week until it reaches 3000 BTC nine weeks after going live. Then, a week later the supply cap will be lifted to 21M TBTC.
If at any point a critical vulnerability is found in the smart contracts, there will be an emergency deposit pause, and a withdrawal of funds followed by a redeploy of the patched contracts as rc.2, resetting the cap schedule. After 6 months without incident, the emergency pause button will be disabled.