Derived unique key per transaction - Wikipedia
https://en.wikipedia.org/wiki/Derived_unique_key_per_transaction
In cryptography, Derived Unique Key Per Transaction (DUKPT) is a key management scheme in which for every transaction, a unique key is used which is derived from a fixed key. Therefore, if a derived key is compromised...
Portable ACR35 RFID NFC Mobile Card Reader for mobile... - AliExpress
https://www.aliexpress.com/i/32810915674.html
It delivers NFC reader functionality and mobility, which allows you to use NFC and contactless applications, even for mobile readers without built-in NFC functionality. ACR35 NFC MobileMate uses AES-128 encryption algorithm and DUKPT Key Management system to secure your data.