Varuna
Varuna is the zero-knowledge proof system that powers the Aleo network. It is a SNARK (succinct non-interactive argument of knowledge) and the successor to the Marlin proof system used in earlier testnets. It produces proofs that a computation was performed correctly without revealing the private inputs.
Varuna uses a universal and updatable structured reference string (SRS), so a single trusted setup ceremony supports circuits of any size up to a predetermined bound. This matters for Aleo because developers deploy arbitrary programs and the proof system must handle variable circuit sizes without per-program setup.
When a user executes an Aleo program function, SnarkVM compiles the function into an arithmetic circuit and Varuna generates a proof over it. The proof is small (a few hundred bytes) and verifiable in milliseconds, regardless of how complex the original computation was. Varuna improves on Marlin with better prover performance and tighter security reductions, which means faster proof generation and stronger cryptographic guarantees.