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A PIN (Personal Identification Number) is a numerical code used to authorize and verify the cardholder in transactions done with debit and credit cards. To protect the PIN during transmission, it must be encrypted using a secure PIN encryption key, which is managed in accordance with PCI PIN Security standards. When a Cardholder enters their PIN at a terminal, the PIN is encrypted by the Nayax terminal using a DUKPT algorithm and sent to the Nayax Engine as a PIN block, which is the encrypted PIN string. Nayax engine sends the PIN Block to MyHSM (Nayax HSM provider) for decryption, then re-encrypts it with a key shared with the Payment Gateway (the integrator).
Master/Session KeyFor Cortina, Nayax supports the Master/Session Key management method only.
  • Master Key is the key exchange key, also known as the Zone Master Key (ZMK).
  • Session Key refers to the PIN encryption key also known as the Zone PIN Key (ZPK).
See the diagram below:

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Supported PIN Exchange Methods

Nayax supports two methods for PIN key exchange and encryption:
  • Manual Key Exchange (Static Key): In this approach, the PIN is encrypted using a long-term cryptographic key known as a Zone PIN Key (ZPK). The ZPK is securely exchanged during the setup phase and is manually loaded into the MyHSM system in accordance with PCI requirements.
  • Dynamic Key Exchange (Master/Session): In this method, the PIN is encrypted using a temporary session key (ZPK), which is dynamically generated and shared via an API by the Payment Gateway. To ensure secure transmission, the session ZPK is encrypted with a static Zone Master Key (ZMK). Like the static ZPK, the ZMK is securely exchanged and preloaded into MyHSM during the initial setup. The PIN exchange process will be initiated by Nayax using Cortina Renew Key endpoint, the interval in which the key is exchanged, is configurable and will be discussed during the setup stage of the integration.
PIN Encryption Algorithm
  • Nayax supports TDEA, 2TDEA, 3TDEA, AES-128 and AES-256
  • Nayax supports ISO 0-4 or ANSI PIN Block format.
Please contact your Nayax Integrator for more details.