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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