Thank you very much for your prompt reply.
As you mentioned, CSP is Cryptographic Service Provider.
KSP stands for "Key Storage Provider" which is a provider like CSP.
KSP is a provider used in CNG(Crptography Next Generation) implemented from Windows Vista.
I want to create SHA-256 signature in Operating System later than Windows Vista.
However, when CSP is specified to create SHA-256 signature, the signature created is SHA-1.
Therfore, I implemented SHA-256 signature using "KSP".
In Acrobat XI, I could create SHA-256 signature by KSP as I expected.
But, in Acrobat X, KSP did not work and I received error message "The keyset is not defined".
(The signature mechanism is same.)
Therefore, I guess that Acrobat X doesn't support KSP.
Is that correct?