/**
 * \file aes_alt.h
 *
 * \brief AES block cipher
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  Copyright (c) 2022, Nuvoton Technology Corporation
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */
#ifndef MBEDTLS_AES_ALT_H
#define MBEDTLS_AES_ALT_H

#include "mbedtls/aes.h"

#if defined(MBEDTLS_AES_ALT)
// Regular implementation
//
#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          AES context structure
 */
typedef struct {
    uint32_t keySize;       /* Key size: 128/192/256 */
    uint32_t keySizeOp;     /* AES_KEY_SIZE_128/192/256 */
    uint32_t encDec;        /* 0: decrypt, 1: encrypt */
    uint32_t opMode;        /* AES_MODE_ECB/CBC/CFB */
    uint32_t iv[4];         /* IV for next block cipher */
    uint32_t keys[8];       /* Cipher key */
}
mbedtls_aes_context;


#if defined(MBEDTLS_CIPHER_MODE_XTS)
#error "Unsupported option MBEDTLS_CIPHER_MODE_XTS defined"
#endif /* MBEDTLS_CIPHER_MODE_XTS */


/**
 * \brief          Initialize AES context
 *
 * \param ctx      AES context to be initialized
 */
void mbedtls_aes_init( mbedtls_aes_context *ctx );

/**
 * \brief          Clear AES context
 *
 * \param ctx      AES context to be cleared
 */
void mbedtls_aes_free( mbedtls_aes_context *ctx );

/**
 * \brief          AES key schedule (encryption)
 *
 * \param ctx      AES context to be initialized
 * \param key      encryption key
 * \param keybits  must be 128, 192 or 256
 *
 * \return         0 if successful, or MBEDTLS_ERR_AES_INVALID_KEY_LENGTH
 */
int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
                            unsigned int keybits );

/**
 * \brief          AES key schedule (decryption)
 *
 * \param ctx      AES context to be initialized
 * \param key      decryption key
 * \param keybits  must be 128, 192 or 256
 *
 * \return         0 if successful, or MBEDTLS_ERR_AES_INVALID_KEY_LENGTH
 */
int mbedtls_aes_setkey_dec( mbedtls_aes_context *ctx, const unsigned char *key,
                            unsigned int keybits );

/**
 * \brief          AES-ECB block encryption/decryption
 *
 * \param ctx      AES context
 * \param mode     MBEDTLS_AES_ENCRYPT or MBEDTLS_AES_DECRYPT
 * \param input    16-byte input block
 * \param output   16-byte output block
 *
 * \return         0 if successful
 */
int mbedtls_aes_crypt_ecb( mbedtls_aes_context *ctx,
                           int mode,
                           const unsigned char input[16],
                           unsigned char output[16] );

#if defined(MBEDTLS_CIPHER_MODE_CBC)
/**
 * \brief          AES-CBC buffer encryption/decryption
 *                 Length should be a multiple of the block
 *                 size (16 bytes)
 *
 * \note           Upon exit, the content of the IV is updated so that you can
 *                 call the function same function again on the following
 *                 block(s) of data and get the same result as if it was
 *                 encrypted in one call. This allows a "streaming" usage.
 *                 If on the other hand you need to retain the contents of the
 *                 IV, you should either save it manually or use the cipher
 *                 module instead.
 *
 * \param ctx      AES context
 * \param mode     MBEDTLS_AES_ENCRYPT or MBEDTLS_AES_DECRYPT
 * \param length   length of the input data
 * \param iv       initialization vector (updated after use)
 * \param input    buffer holding the input data
 * \param output   buffer holding the output data
 *
 * \return         0 if successful, or MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH
 */
int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx,
                           int mode,
                           size_t length,
                           unsigned char iv[16],
                           const unsigned char *input,
                           unsigned char *output );
#endif /* MBEDTLS_CIPHER_MODE_CBC */

#if defined(MBEDTLS_CIPHER_MODE_CFB)
/**
 * \brief          AES-CFB128 buffer encryption/decryption.
 *
 * Note: Due to the nature of CFB you should use the same key schedule for
 * both encryption and decryption. So a context initialized with
 * mbedtls_aes_setkey_enc() for both MBEDTLS_AES_ENCRYPT and MBEDTLS_AES_DECRYPT.
 *
 * \note           Upon exit, the content of the IV is updated so that you can
 *                 call the function same function again on the following
 *                 block(s) of data and get the same result as if it was
 *                 encrypted in one call. This allows a "streaming" usage.
 *                 If on the other hand you need to retain the contents of the
 *                 IV, you should either save it manually or use the cipher
 *                 module instead.
 *
 * \param ctx      AES context
 * \param mode     MBEDTLS_AES_ENCRYPT or MBEDTLS_AES_DECRYPT
 * \param length   length of the input data
 * \param iv_off   offset in IV (updated after use)
 * \param iv       initialization vector (updated after use)
 * \param input    buffer holding the input data
 * \param output   buffer holding the output data
 *
 * \return         0 if successful
 */
int mbedtls_aes_crypt_cfb128( mbedtls_aes_context *ctx,
                              int mode,
                              size_t length,
                              size_t *iv_off,
                              unsigned char iv[16],
                              const unsigned char *input,
                              unsigned char *output );

/**
 * \brief          AES-CFB8 buffer encryption/decryption.
 *
 * Note: Due to the nature of CFB you should use the same key schedule for
 * both encryption and decryption. So a context initialized with
 * mbedtls_aes_setkey_enc() for both MBEDTLS_AES_ENCRYPT and MBEDTLS_AES_DECRYPT.
 *
 * \note           Upon exit, the content of the IV is updated so that you can
 *                 call the function same function again on the following
 *                 block(s) of data and get the same result as if it was
 *                 encrypted in one call. This allows a "streaming" usage.
 *                 If on the other hand you need to retain the contents of the
 *                 IV, you should either save it manually or use the cipher
 *                 module instead.
 *
 * \param ctx      AES context
 * \param mode     MBEDTLS_AES_ENCRYPT or MBEDTLS_AES_DECRYPT
 * \param length   length of the input data
 * \param iv       initialization vector (updated after use)
 * \param input    buffer holding the input data
 * \param output   buffer holding the output data
 *
 * \return         0 if successful
 */
int mbedtls_aes_crypt_cfb8( mbedtls_aes_context *ctx,
                            int mode,
                            size_t length,
                            unsigned char iv[16],
                            const unsigned char *input,
                            unsigned char *output );
#endif /*MBEDTLS_CIPHER_MODE_CFB */

#if defined(MBEDTLS_CIPHER_MODE_CTR)
/**
 * \brief               AES-CTR buffer encryption/decryption
 *
 * Warning: You have to keep the maximum use of your counter in mind!
 *
 * Note: Due to the nature of CTR you should use the same key schedule for
 * both encryption and decryption. So a context initialized with
 * mbedtls_aes_setkey_enc() for both MBEDTLS_AES_ENCRYPT and MBEDTLS_AES_DECRYPT.
 *
 * \param ctx           AES context
 * \param length        The length of the data
 * \param nc_off        The offset in the current stream_block (for resuming
 *                      within current cipher stream). The offset pointer to
 *                      should be 0 at the start of a stream.
 * \param nonce_counter The 128-bit nonce and counter.
 * \param stream_block  The saved stream-block for resuming. Is overwritten
 *                      by the function.
 * \param input         The input data stream
 * \param output        The output data stream
 *
 * \return         0 if successful
 */
int mbedtls_aes_crypt_ctr( mbedtls_aes_context *ctx,
                           size_t length,
                           size_t *nc_off,
                           unsigned char nonce_counter[16],
                           unsigned char stream_block[16],
                           const unsigned char *input,
                           unsigned char *output );
#endif /* MBEDTLS_CIPHER_MODE_CTR */

/**
 * \brief           Internal AES block encryption function
 *                  (Only exposed to allow overriding it,
 *                  see MBEDTLS_AES_ENCRYPT_ALT)
 *
 * \param ctx       AES context
 * \param input     Plaintext block
 * \param output    Output (ciphertext) block
 */
void mbedtls_aes_encrypt( mbedtls_aes_context *ctx,
                          const unsigned char input[16],
                          unsigned char output[16] );

/**
 * \brief           Internal AES block decryption function
 *                  (Only exposed to allow overriding it,
 *                  see MBEDTLS_AES_DECRYPT_ALT)
 *
 * \param ctx       AES context
 * \param input     Ciphertext block
 * \param output    Output (plaintext) block
 */
void mbedtls_aes_decrypt( mbedtls_aes_context *ctx,
                          const unsigned char input[16],
                          unsigned char output[16] );

#ifdef __cplusplus
}
#endif


#endif /* MBEDTLS_AES_ALT */

#endif /* aes_alt.h */
