Chapter 3 Key Info Types 251
KI_DES24Strong
KI_DES24Strong
Purpose:
This KI allows you to specify a 24-byte key used by the Triple DES algorithm. The key
object will satisfy the DES parity requirement and will be checked against known DES
weak keys.
Type of information this allows you to use:
24-byte value for a Triple DES key where the information stored in the key object will
be DES parity-adjusted according to FIPS 46-1. Crypto-C treats the least significant bit
of each byte of the key data as the DES parity-adjustment bit. When setting a key
object with this KI, Crypto-C will check the input data against a list of known DES
weak keys. If the resulting key would be weak, Crypto-C returns an error.
Format of info supplied to B_SetKeyInfo:
pointer to an unsigned char array that holds the 24-byte Triple DES key. The key is
DES parity adjusted when it is copied to the key object.
Format of info returned by B_GetKeyInfo:
pointer to an unsigned char array that holds the 24-byte Triple DES key that is DES
parity adjusted.
Can get this info type if key object already has:
KI_DES24Strong, KI_24Byte (if the key is not weak), KI_Item (if the length of the ITEM
is 24 and the key is not weak),
KI_DESX (if the key is not weak).
