What is Truebit on Ethereum?

Truebit on Ethereum (v1) is a first-generation verification protocol designed for use with Ethereum smart contracts. Truebit will continue to provide support for Truebit on Ethereum during the early access program for Truebit Verify, our next-generation platform.
Truebit on Ethereum is a blockchain enhancement which enables Ethereum smart contracts to securely perform complex computations in supported programming languages at reduced gas costs. As described in our original whitepaper and this overview, Truebit on Ethereum verifies the correctness of offchain computation via an interactive verification protocol. You may wish to familiarize yourself with the practical, high-level user guide before proceeding.
While smart contracts can perform small computations correctly, large computation tasks pose security risks for blockchains. Truebit on Ethereum counteracts this shortcoming via a trustless, retrofitting oracle which correctly performs computational tasks. Any smart contract can issue a computation task to this oracle in the form of WebAssembly bytecode, while anonymous “miners” receive rewards for correctly solving the task.
The oracle’s protocol guarantees correctness in two layers: a unanimous consensus layer where anyone can object to faulty solutions, and an on-chain mechanism which incentivizes participation and ensures fair remuneration. These components formally manifest themselves through a combination of novel, off-chain architecture and on-chain smart contracts.
Rather than relying on external, cryptographic proofs of correctness, Truebit on Ethereum leverages game theoretic principles to effectively increase the on-chain computation power of existing networks.