Groth16

Groth16 is a highly efficient zk-SNARK proving system introduced by Jens Groth in 2016 that produces constant-size proofs (128 bytes: two G1 points and one G2 point on a pairing-friendly elliptic curve) with constant-time verification regardless of circuit complexity, making it the preferred proof system for on-chain verification where calldata and compute costs are constrained. Light Protocol uses Groth16 proofs over the BN254 curve (known as alt_bn128 in Ethereum tooling) to verify compressed account state transitions on Solana, leveraging the native alt_bn128 pairing and point-addition syscalls added to the SVM to keep verification within the per-transaction compute unit limit. The trade-off is that Groth16 requires a trusted setup ceremony per circuit, producing a structured reference string (SRS) whose security relies on participants honestly discarding their toxic waste.