Common Data Security Architecture (CDSA) White Paper

Chapter 1 69

Validating the CSP Credentials

Figure 1-11 Verifying the validity of the CSP library

5. If the values match, the shared library is loaded. If the hashes do not match, CDSA

execution will terminate.

The Self Check

Once an HP-UX shared library is loaded, it is initialized. Then control is returned to the

function that initiated loading of the shared library.

In the self check, the CSP add-in module that has just been loaded checks itself, to make sure

it has not been tampered with.

1. The signer’s public key is extracted from the CSP shared library and used to directly verify

the signature on .SF ﬁle. No chaining validation is necessary.

2. After the signature is validated, the SHA-1 hash of the section in the .MF ﬁle referring to

the shared library just loaded is calculated and compared with the hash in the .SF ﬁle.

3. If these hashes match, a hash of the CSP shared library is calculated and compared to the

hash in the .MF ﬁle.

4. If the hash matches (indicating the .MF ﬁle has not been tampered with), control is

returned back to the function which initiated loading of the shared library.

CSP file

.MF file, containing hash of

shared library and library name

SHA-1

HASH

function

Are

SHA-1

hashes

equal?

CSP shared library is valid

.CSP shared

library has been

tampered with.

STOP!

Yes