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PIN Block Format 1

Calculate ISO 9564-1 Format 1 (ECI-4) PIN blocks with random fill — no PAN required. Optional 3DES encryption with a Zone PIN Key.

🔢 PIN

4–12 numeric digits. Spaces are allowed.

🔑 Zone PIN Key (Optional)

Optional. 16-byte double-length 3DES key (32 hex chars). If provided, the clear PIN block is encrypted with 3DES-ECB.

How it works: ISO 9564-1 Format 1 (also known as ECI-4) is a PIN block format that does not require a Primary Account Number (PAN).

PIN Field: 1 (format nibble) + PIN length (1 hex nibble) + PIN digits. For PIN "1234": 141234.

Random Fill: The remaining nibbles are filled with cryptographically random hex values to pad the block to 16 hex characters (8 bytes). This ensures each PIN block is unique even for the same PIN.

Key Difference from Format 0: Format 0 XORs the PIN field with a PAN-derived field, binding the PIN block to a specific card. Format 1 uses random fill instead, making it suitable for environments where PAN data is unavailable.

Encryption: In production, the clear PIN block is encrypted with a Zone PIN Key (ZPK) using 3DES-ECB before transmission. The ZPK is a double-length key (32 hex chars = 16 bytes) shared between HSMs.

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📖 About This Tool

What is the PIN Block Format 1 Calculator?

The PIN Block Format 1 Calculator computes PIN blocks per ISO 9564-1 Format 1 (ECI-4). Unlike Format 0, it does not use the PAN and instead pads with random data, providing better security when the PAN is not available.

🛠️ How to Use
  1. Enter the clear PIN (4-12 digits).
  2. Click Calculate to generate the Format 1 PIN block with random padding.
  3. Each calculation produces a different result due to random padding.
❓ FAQ

When is Format 1 used instead of Format 0?

Format 1 is used when the PAN is not available or to avoid PAN dependency in PIN blocks. Since it uses random padding instead of PAN digits, each calculation produces a unique PIN block, adding an element of randomness.