Zero-Knowledge Proofs (ZKPs)

Zero-Knowledge Proofs (ZKPs) allow one party (prover) to convince another (verifier) that a statement is true without revealing any additional information. In blockchain consensus, ZKPs enhance privacy and efficiency.

Applications in consensus:

• Privacy-preserving transactions: Validators can confirm the correctness of transactions without knowing the exact amounts or participants.
• Efficient validation: Proofs allow verification without exposing the full dataset, reducing bandwidth and storage requirements.

Example – zk-SNARKs in Ethereum or Zcash:

• A user proves that they have enough balance to make a transaction without revealing the exact balance.
• The network verifies the proof cryptographically → transaction is accepted.
• Validators don’t see the transaction details, only the proof of correctness.

Role of Cryptography:

• ZKPs rely on advanced cryptographic constructs (elliptic curves, hash functions, and commitments).
• They provide confidentiality, integrity, and trust without compromising decentralization.
• They are increasingly used in Layer-2 scaling solutions and privacy-focused blockchains.

Summary:

• PoW: Uses SHA-256 hash puzzles to enforce computational work → secure, tamper-resistant, but energy-intensive.
• PoS: Uses digital signatures and random selection → energy-efficient, relies on stake and cryptographic verification.
• ZKPs: Use advanced cryptography to verify correctness without revealing data → enhances privacy and scalability.

Cryptography underpins all these consensus mechanisms, providing security, integrity, and trust in a decentralized network.