Starknet is a permissionless Validity-Rollup, also known as a "ZK-Rollup," that facilitates general computation. Currently, it operates in production as an L2 network on Ethereum. The ultimate security of Starknet on L1 is guaranteed by employing the safest and most scalable cryptographic proof system. Starknet contracts are (for the most part) written in the Cairo language – A Turing complete programming language designed for STARK proofs.