Current key serial number

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The current key serial number is the concatenation of the initial key serial number (a 59-bit value) and the encryption counter (a 21-bit value).

The concatenation is an 80-bit (10-byte) value. Table 1 shows the format of the current key serial number.

When UKPT or DUKPT is specified, the PIN profile parameter is extended to a 48-byte field and must contain the current key serial number.

Table 1. Format of the Current Key Serial Number Field

Format of the Current Key Serial Number Field
Bytes Description
24 - 47 Character representation of the current key serial number used to derive the initial PIN encrypting key. It is left-aligned and padded with 4 blanks.