DUKPT stands for Derived Unique Key Per Transaction. Which option is the correct expansion?

• A. Derived Unique Key Per Transaction
• B. Direct Unlock Key Protocol
• C. Dual Unique Key Transport
• D. Data Update Key Transfer

Answer: (A)

In payment security, DUKPT is a key management approach where a single base key is used to derive a different cryptographic key for each transaction. Derived means the per-transaction key is generated from the base key rather than stored or used as a static key. Unique ensures every transaction uses its own distinct key, so compromising one key doesn’t expose others. Key refers to the cryptographic material used for encryption/decryption or MACs, and Per Transaction makes clear the scope is every individual transaction. That combination matches the phrase “Derived Unique Key Per Transaction.” The other options describe unrelated concepts and aren’t how DUKPT is defined.