Research on Non-Interactive Zero-Knowledge (NIZK) proof-based blockchain privacy and security focuses on enabling participants to prove the validity of a transaction or computation without revealing any underlying data and without requiring back-and-forth interaction. By integrating NIZK proofs into blockchain systems, users can verify ownership, correctness of smart contract execution, or compliance with protocol rules while maintaining full confidentiality. This approach enhances privacy, prevents double-spending, and strengthens trust in decentralized networks, particularly in cryptocurrency, voting, and confidential transaction applications. Studies also examine the trade-offs between proof size, computational overhead, and scalability, as well as the combination of NIZK with other cryptographic techniques such as ring signatures or homomorphic encryption to achieve stronger security guarantees. Overall, NIZK proof-based methods provide a powerful framework for privacy-preserving and secure blockchain operations.