About ECDSA

The ECDSA (Elliptic Curve Digital Signature Algorithm) in this document is the one described in the ANSI X9.62 working draft specification of November 17, 1997. It is hoped that the parts of this document that Cryptoki references will not change in the final ANSI X9.62 document, but there is no guarantee that this will be the case.

In this working draft, there are 3 different varieties of ECDSA defined:

ECDSA using a field with an odd prime number of elements.
ECDSA using a field of characteristic 2 whose elements are represented using a polynomial basis.
ECDSA using a field of characteristic 2 whose elements are represented using an optimal normal basis.

An ECDSA key in Cryptoki contains information about which variety of ECDSA it is suited for. It is preferable that a Cryptoki library which can perform ECDSA mechanisms be capable of performing operations with all 3 varieties of ECDSA; however, this is not required.

If an attempt to create, generate, derive, or unwrap an ECDSA key of an unsupported variety (or of an unsupported size of a supported variety) is made, that attempt should fail with the error code CKR_TEMPLATE_INCONSISTENT.

RSA Security Inc. Public-Key Cryptography Standards - PKCS#11 - v210