Interbank PIN Generation algorithm

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A description of the Interbank PIN calculation method.

The Interbank PIN calculation method consists of the following steps:
  1. Let X denote the transaction_security parameter element converted to an array of 16 4-bit numeric values. This parameter consists of (in the following sequence) the 11 rightmost digits of the customer PAN (excluding the check digit), a constant of 6, a 1-digit key indicator, and a 3-digit validation field.
  2. Encrypt X with the double-length PINGEN (or PINVER) key to get 16 hexadecimal digits (64 bits).
  3. Perform decimalization on the result of the previous step by scanning the 16 hexadecimal digits from left to right, skipping any digit greater than X'9' until 4 decimal digits (for example, digits that have values from X'0' - X'9') are found.

    If all digits are scanned but 4 decimal digits are not found, repeat the scanning process, skipping all digits that are X'9' or less and selecting the digits that are greater than X'9'. Subtract 10 (X'A') from each digit selected in this scan.

    If the 4 digits that were found are all zeros, replace the 4 digits with 0100.

  4. Concatenate and use the resulting digits for the Interbank PIN. The 4-digit PIN consists of the decimal digits in the sequence in which they are found.