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CCA Release 2.54
S/390 Based Master Key Verification Method
When the first and third portions of the symmetric master key have the same value,
the master key is effectively a double-length DES key. In this case, the master key
verification pattern (MKVP) is based on this algorithm:
C = X'4545454545454545'
IR = MK
first-part
⊕ e
C
(MK
first-part
)
MKVP = MK
second-part
⊕ e
IR
(MK
second-part
)
where:
e
x
(Y) is the DES encoding of Y using x as a key
⊕ represents the bit-wise exclusive-OR function.
Version X'00' internal DES key tokens use this eight-byte master key verification
pattern.
Asymmetric Master Key MDC-Based Verification Method
The verification pattern for the asymmetric master keys is based on hashing the
value of the master key using the MDC-4 hashing algorithm. Note that the master
key is not parity adjusted.
The RSA private key sections X'06' and X'08' use this 16-byte master key
verification pattern.
Key Token Verification Patterns
The verification pattern techniques used in the several types of key tokens are:
DES key tokens:
– Triple-length master key, key token version X'00': eight-byte SHA-1
– Triple-length master key, key token version X'03': two-byte SHA-1
– Double-length master key, key token version X'00': eight-byte S/390
– Double-length master key, key token version X'03': two-byte SHA-1.
RSA key tokens:
– Private-key section types X'06' and X'08': MDC-based
– Private-key section types X'02' and X'05': two-byte SHA-1.
CCA DES-Key Verification Algorithm
The cryptographic engines provide a method for verifying the value of a DES
cryptographic key or key part without revealing information about the value of the
key or key part.
The CCA verification method first creates a random number. A one-way
cryptographic function combines the random number with the key or key part. The
verification method returns the result of this one-way cryptographic function (the
verification pattern) and the random number.
Note: A one-way cryptographic function is a function in which it is easy to
compute the output from a given input, but it is computationally infeasible to
compute the input given an output.
For information about how you can use an application program to invoke this
verification method, see page 5-58.
D-2 IBM 4758 CCA Basic Services, Release 2.54, February 2005