AES Full-XTS APIs - zpc/aes_xts_full.h

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In file zpc/aes_xts_full.h, libzpc provides an encryption API for the advanced encryption standard (AES) block cipher in XEX-based Tweaked-codebook mode with the ciphertext stealing (XTS) mode of operation.

In contrast to the AES XTS API, the AES full-XTS API uses full-XTS protected keys containing two single AES keys in one single protected key. This feature requires MSA 10.

Data structures

The context of an AES full-XTS operation is stored in objects of type

struct zpc_aes_xts_full;

Context objects must not be shared among multiple threads. They may be used for multiple operations by setting or resetting the key or initialization vector.

zpc_aes_xts_full_alloc

Purpose: Allocate a new context for an AES-XTS operation to be used with an AES full-XTS key object.

Format:


int zpc_aes_xts_full_alloc (
    struct zpc_aes_xts_full **ctx);

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_set_key

Purpose: Set the AES full-XTS key to be used in the context of an AES-XTS operation.

Format:


int zpc_aes_xts_full_set_key (
    struct zpc_aes_xts_full *ctx, 
    struct zpc_aes_xts_key *key);

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.
input	key	Pointer to an AES full-XTS key .

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_set_iv

Purpose: Set the initialization vector to be used in the context of an AES-XTS operation.

Format:


int zpc_aes_xts_full_set_iv (
    struct zpc_aes_xts_full *ctx, 
    const unsigned char *iv);

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.
input	iv	Pointer to a 16 byte initialization vector buffer.

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_export

Purpose: Get the intermediate state information used in the context of an AES-XTS operation.

Format:


int zpc_aes_xts_full_export (
    struct zpc_aes_xts_full *ctx, 
    unsigned char state[32]);

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.
output	state	Application-provided buffer of 32 bytes to receive the 32 byte intermediate state information.

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_import

Purpose: Set the intermediate state information to be used in the context of an AES-XTS operation.

Format:


int zpc_aes_xts_full_import (
    struct zpc_aes_xts_full *ctx, 
    const unsigned char state[32])

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.
input	state	Buffer of 32 bytes containing the intermediate state information as obtained via zpc_aes_xts_full_export()..

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_encrypt

Purpose: Perform an AES-XTS encryption operation.

Format:


int zpc_aes_xts_full_encrypt (
    struct zpc_aes_xts_full *ctx, 
    unsigned char *ct, 
    const unsigned char *pt, 
    size_t ptlen);

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.
output	ct	Pointer to a ciphertext buffer.
input	pt	Pointer to a plaintext buffer.
input	ptlen	Plaintext length [bytes].

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_decrypt

Purpose: Perform an AES-XTS decryption operation.

Format:


int zpc_aes_xts_full_decrypt (
    struct zpc_aes_xts_full *ctx, 
    unsigned char *pt, 
    const unsigned char *ct, 
    size_t ctlen)

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.
output	pt	Pointer to a plaintext buffer.
input	ct	Pointer to a ciphertext buffer.
input	ctlen	Ciphertext length [bytes].

Return codes:

0 on success. Otherwise, a non-zero error code is returned.

zpc_aes_xts_full_free

Purpose: Free an AES full-XTS context.

Format:


int zpc_aes_xts_full_free (
    struct zpc_aes_xts_full **ctx)

Parameters:


Direction	Name	Description
input, output	ctx	Pointer to an AES full-XTS context.