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UDK Calculator

Derive ICC Master Keys from Issuer Master Keys per EMV Book 2 Annex A1.4 — Method A & B with DES parity adjustment

🔑 Input

Double-length 3DES Issuer Master Key. Spaces are allowed.

Decimal digits only. PAN > 16 digits automatically triggers Method B (SHA-1 based).

2-digit sequence number (00–99). Defaults to 00 if omitted.

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📖 About This Tool

What is the UDK Calculator?

The UDK Calculator derives Unique Derivation Keys from an Issuer Master Key and PAN/PAN Sequence Number per EMV specifications. UDKs are card-specific keys used for ARQC generation and issuer script encryption.

🛠️ How to Use
  1. Enter the Issuer Master Key (IMK) in hexadecimal.
  2. Enter the PAN and PAN Sequence Number.
  3. Click Calculate to derive the UDK.
❓ FAQ

What is a UDK?

A UDK (Unique Derivation Key) is a card-specific cryptographic key derived from the Issuer Master Key using the PAN and PAN Sequence Number. Each card gets a unique key for cryptogram generation (ARQC) and secure messaging.