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💳 Card Data

13–19 digit card number. Used as validation data for PIN derivation.

🔑 Key & Parameters

16 hex chars (single DES) or 32 hex chars (3DES double-length key).

16 digits mapping hex 0-F to decimal 0-9. Default: 0123456789012345

Number of digits for the PIN and offset.

The customer's desired PIN. Must match the selected PIN length.

The stored offset value. Must match the selected PIN length.

How it works: The IBM 3624 PIN Offset is the digit-by-digit modulo-10 difference between a customer's chosen PIN and the system-generated Natural PIN. The issuer stores only the offset — never the actual PIN.

Calculate Offset: For each digit position i: offset[i] = (customerPIN[i] − naturalPIN[i] + 10) mod 10

Verify PIN: For each digit position i: customerPIN[i] = (naturalPIN[i] + offset[i]) mod 10

Example: If the Natural PIN is 3846 and Customer PIN is 1234, the offset is 8498 (digit-by-digit: 1−3+10=8, 2−8+10=4, 3−4+10=9, 4−6+10=8).

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📖 About This Tool

What is the IBM 3624 PIN Offset Calculator?

The IBM 3624 PIN Offset Calculator computes the offset value between a customer-selected PIN and the natural (intermediate) PIN. The offset is stored instead of the PIN itself, enabling secure PIN verification.

🛠️ How to Use
  1. Enter the PIN Verification Key.
  2. Enter the PAN and decimalization table.
  3. Enter the customer-selected PIN.
  4. Click Calculate to generate the offset.
FAQ

What is a PIN offset?

The PIN offset is the digit-by-digit modulo-10 difference between the customer-selected PIN and the IBM 3624 natural PIN. Storing only the offset (not the PIN) enables PIN verification without exposing the actual PIN value.