Non-Interactive Zero-Knowledge Proofs extend the concept of zero-knowledge proofs, where the prover can demonstrate knowledge of a certain piece of information (like a secret key) without actually disclosing the information itself. Unlike traditional zero-knowledge proofs that require interaction between the prover and verifier, NIZKPs use a common reference string (CRS) that both parties agree upon beforehand. This setup allows the proof to be generated and verified independently, making NIZKPs particularly useful in scenarios where interaction may be impractical or insecure.