Cryptographic Token Interface Standard

PKCS#11

General-length AES-CMAC

General-length AES-CMAC, denoted CKM_AES_CMAC_GENERAL, is a mechanism for single- and multiple-part signatures and verification, based on [ NIST sp800-38b] and [ RFC 4493]. NIST Special Publication 800-38B [2] and RFC 4493 [3].

It has a parameter, a CK_MAC_GENERAL_PARAMS structure, which specifies the output length desired from the mechanism.

The output bytes from this mechanism are taken from the start of the final AES cipher block produced in the MACing process.

Constraints on key types and the length of data are summarized in the following table: 




 Table 246, General-length AES-CMAC: Key And Data Length   
Function Key type 

Data length

 

Signature length

   


C_Sign CKK_AES 

any

 

0-block size, as specified in parameters

   


C_Verify CKK_AES 

any

 

0-block size, as specified in parameters

  

 



References [NIST sp800-38b] and [RFC 4493] recommend that the output MAC is not truncated to less than 64 bits. The MAC length must be specified before the communication starts, and must not be changed during the lifetime of the key. It is the caller's responsibility to follow these rules.


For this mechanism, the ulMinKeySize and ulMaxKeySize  fields of the CK_MECHANISM_INFO structure specify the supported range of AES key sizes, in bytes.


 
 



RSA Security Inc. Public-Key Cryptography Standards - 
PKCS#11 - v230