Groth16

The industry standard zk-SNARK for constant-size proofs and lightning-fast verification on Ethereum.

Groth16 remains the most widely deployed zero-knowledge proof system in production (powering protocols like Zcash and Tornado Cash). It generates compact proofs of just 128 bytes regardless of circuit complexity, making it the premier choice for gas-efficient on-chain verification. While it requires a per-circuit trusted setup (the powers-of-tau ceremony), the performance trade-off is unmatched: verification takes less than 1ms on standard hardware. It is the definitive benchmark for pairing-based SNARKs using the BLS12-381 curve.

https://eprint.iacr.org/2016/260