Why did Kaspa choose RISC Zero for its initial zero-knowledge proof system?

Kaspa's KIP-0016 selected RISC Zero as its initial zero-knowledge virtual machine (zkVM) because of its production maturity and proven architecture. RISC Zero is one of the longer-running zkVM projects, offering both STARK proofs (quantum-resistant but larger) and Groth16 proofs (compact but not quantum-safe). Its recursion architecture — using lift and join programs — compresses large execution traces into constant-size proofs, which is critical when verifying proofs on-chain where resources are bounded. Independent benchmarking by VAC Research also found RISC Zero to be the fastest system for their particular use case, providing third-party validation of its performance. Understanding which proof system underlies Kaspa's zero-knowledge features matters because it determines the security model and efficiency of transactions that rely on those proofs.