Zero-Knowledge Proofs (ZKPs) are cryptographic methods that allow one party to prove to another that a statement is true without revealing any information beyond the validity of the statement itself. The 'Cost per Transaction' feature specifically measures the average cost incurred when executing transactions that leverage ZKPs. This cost can include computational resources, network fees, and any additional overhead associated with the cryptographic processes involved. Understanding this cost is crucial for businesses and developers as it impacts the overall efficiency and scalability of blockchain applications that utilize ZKPs, particularly in scenarios requiring privacy and confidentiality.