Enigma: Decentralized Computation Platform with
Guaranteed Privacy. pdf 
Secure multi-party computation is a subfield of cryptography with the goal of creating methods for parties to jointly compute a function over their inputs while keeping those inputs private. wikipedia
The intense verification and public nature of the blockchain limits potential use cases, however. Modern applications use huge amounts of data, and run extensive analysis on that data. This restriction means that only fiduciary code can run on the blockchain. The problem is, much of the most sensitive parts of modern applications require heavy processing on private data.
Enigma is designed to connect to an existing blockchain and off-load private and intensive computations to an off-chain network. All transactions are facilitated by the blockchain, which enforces access-control based on digital signatures and programmable permissions.