What is a zero-knowledge proof?
A zero-knowledge proof (ZKP) is a cryptographic protocol that lets one party (the prover) convince another (the verifier) that a statement is true — without revealing any information beyond the statement’s validity itself. ZKPs were formalised by Goldwasser, Micali and Rackoff in 1985 and became commercially relevant in blockchain with zk-SNARK constructions (Zcash 2016, Ethereum L2s 2022-25).
ZKP families in production
- zk-SNARKs (Succinct Non-interactive Argument of Knowledge): small proofs, fast verification; require trusted setup (Groth16) or universal setup (PLONK). Used by Zcash, zkSync, Polygon zkEVM, Mina.
- zk-STARKs (Scalable Transparent Argument of Knowledge): no trusted setup, post-quantum candidate; larger proofs. Used by Starknet, Polygon Miden.
- Bulletproofs: no setup, smaller than STARKs but slower verification; used by Monero confidential transactions.
Use cases beyond scaling
- Privacy: shielded transactions (Zcash, Aztec, Railway).
- Identity: selective-disclosure credentials (zkPassport, Sismo, World ID).
- Compliance: proving regulatory eligibility (accredited investor, sanctions clearance) without revealing identity.
- ZK-rollups: compressing L2 execution into a single validity proof posted to L1.
Türk fintech ve KVKK bağlamı
ZK ispatlar veri minimizasyonu (KVKK Madde 4(d)) ve “tasarım gereği gizlilik” (GDPR Madde 25) ilkesi için güçlü bir teknik araçtır — örneğin yaş doğrulama veya gelir eşiği için doğum tarihi veya tam gelir paylaşımı gerekmez. Türk fintech’lerin KYC ve risk skorlama mimarilerinde ZK adoption henüz erken aşamadadır; ancak AB AI Act ve eIDAS 2.0 ZK temelli kimlik doğrulamayı önümüzdeki dönemde teşvik edecektir.
Do: evaluate ZK for privacy-preserving compliance flows (age, residency, income thresholds); benchmark prover/verifier costs.
Don’t: assume “ZK = anonymous” — careful protocol design is needed; metadata and on-chain side-channels can leak identity.