CKM_SEED_CBC

Supported Operations

Encrypt and Decrypt Yes
Sign and Verify No
SignRecover and VerifyRecover No
Digest No
Generate Key/Key-Pair No
Wrap and Unwrap Yes
Derive No
Available in FIPS Mode No

Key Size Range (bytes) and Parameters

Minimum 16
Maximum 16
Parameter 16 bytes

Description

SEED-CBC, denoted CKM_SEED_CBC, is a mechanism for single and multiple part encryption and decryption, key wrapping and key unwrapping, based on the KISA (Korean Information Security Agency) SEED specification and cipher-block chaining mode.

It has a single parameter; a 16-byte initialization vector.

This mechanism can wrap and unwrap any secret key.  Of course, a particular token may not be able to wrap/unwrap every secret key that it supports.  For wrapping, the mechanism encrypts the value of the CKA_VALUE attribute of the key that is wrapped, padded on the trailing end with up to block size minus one null bytes so that the resulting length is a multiple of the block size. The output data is the same length as the padded input data. It does not wrap the key type, key length, or any other information about the key; the application must convey these separately.

For unwrapping, the mechanism decrypts the wrapped key, and truncates the result according to the CKA_KEY_TYPE attribute of the template and, if it has one and the key type supports it, the CKA_VALUE_LEN attribute of the template.  The mechanism contributes the result as the CKA_VALUE attribute of the new key. Other attributes required by the key type must be specified in the template.

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

Table 1: SEED-CBC: Key and Data Length
Function Key Type Input Length Output Length Comments
C_Encrypt CKK_SEED Multiple of block size Same as input length No final part
C_Decrypt CKK_SEED Multiple of block size Same as input length No final part
C_WrapKey CKK_SEED Any Input length rounded up to multiple of the block size  
C_UnwrapKey CKK_SEED Multiple of block size Determined by type of key being unwrapped or CKA_VALUE_LEN  

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