IBM Computer Hardware 2 User Manual download pdf (Page 208)

Key_Test CCA Release 2.54

Key_Test (CSNBKYT)

Platform/

Product

OS/2 AIX Win NT/

2000

OS/400

IBM 4758-2/23 X X X X

You use the Key_Test verb to verify the value of a key or key-part. Several

verification algorithms are supported. The verb supports testing of clear keys,

enciphered keys, master keys, and key-parts. The verification pattern and the

verification processes do not reveal the value of an encrypted key, other than

equivalency of two key values.

The verb operates in either a GENERATE or VERIFY mode that you specify with a

rule-array keyword. You also specify the type of key or key-part.

If you test one of the master keys (keywords KEY-KM, KEY-NKM, or KEY-OKM)

you may specify which class of master key to test, either symmetric or asymmetric,

using the SYM-MK and the ASYM-MK rule-array keywords. If you do not select a

master-key class, the verb requires that both selected asymmetric and symmetric

master-keys have the same value. There are three verification methods that apply.

See “Master Key Verification Algorithms” on page D-1.

For historical reasons, the verification information is passed in two 8-byte variables,

random_number and verification_pattern. For simplicity, these variables can be two

8-byte elements of a 16-byte array and processed by your application as a single

quantity. Both parameters must be coded when calling the API.

 When the verb generates a verification pattern, it returns information in the

random number and verification pattern variables.

 When the verb tests a verification pattern, it uses information supplied in the

random number and verification pattern variables. Supply the verification data

and random number from a previous procedure call to the Key_Test verb. The

verb returns the verification results in the form of a return code. If verification

fails, the verb returns a return code of four and reason code of one.

For certain types of keys, you can specify an alternative key-test algorithm using a

rule-array keyword. The algorithms are explained in “Cryptographic Key Verification

Techniques” on page D-1.

 Except for master keys, you can specify the ENC-ZERO algorithm. The

verification information is provided in the four high-order bytes of the verification

pattern variable.

 For master keys, you can specify the MDC-4 algorithm.

Specify the type of key or key-part with a rule-array keyword: master key, clear or

enciphered, and so forth.

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IBM Computer Hardware 2 User Manual Page 208