|  | /** | 
|  | * \file aes.h | 
|  | * | 
|  | * \brief   This file contains AES definitions and functions. | 
|  | * | 
|  | *          The Advanced Encryption Standard (AES) specifies a FIPS-approved | 
|  | *          cryptographic algorithm that can be used to protect electronic | 
|  | *          data. | 
|  | * | 
|  | *          The AES algorithm is a symmetric block cipher that can | 
|  | *          encrypt and decrypt information. For more information, see | 
|  | *          <em>FIPS Publication 197: Advanced Encryption Standard</em> and | 
|  | *          <em>ISO/IEC 18033-2:2006: Information technology -- Security | 
|  | *          techniques -- Encryption algorithms -- Part 2: Asymmetric | 
|  | *          ciphers</em>. | 
|  | * | 
|  | *          The AES-XTS block mode is standardized by NIST SP 800-38E | 
|  | *          <https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-38e.pdf> | 
|  | *          and described in detail by IEEE P1619 | 
|  | *          <https://ieeexplore.ieee.org/servlet/opac?punumber=4375278>. | 
|  | */ | 
|  |  | 
|  | /* | 
|  | *  Copyright The Mbed TLS Contributors | 
|  | *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later | 
|  | */ | 
|  |  | 
|  | #ifndef MBEDTLS_AES_H | 
|  | #define MBEDTLS_AES_H | 
|  |  | 
|  | #if !defined(MBEDTLS_CONFIG_FILE) | 
|  | #include "mbedtls/config.h" | 
|  | #else | 
|  | #include MBEDTLS_CONFIG_FILE | 
|  | #endif | 
|  | #include "mbedtls/platform_util.h" | 
|  |  | 
|  | #include <stddef.h> | 
|  | #include <stdint.h> | 
|  |  | 
|  | /* padlock.c and aesni.c rely on these values! */ | 
|  | #define MBEDTLS_AES_ENCRYPT     1 /**< AES encryption. */ | 
|  | #define MBEDTLS_AES_DECRYPT     0 /**< AES decryption. */ | 
|  |  | 
|  | /* Error codes in range 0x0020-0x0022 */ | 
|  | /** Invalid key length. */ | 
|  | #define MBEDTLS_ERR_AES_INVALID_KEY_LENGTH                -0x0020 | 
|  | /** Invalid data input length. */ | 
|  | #define MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH              -0x0022 | 
|  |  | 
|  | /* Error codes in range 0x0021-0x0025 */ | 
|  | /** Invalid input data. */ | 
|  | #define MBEDTLS_ERR_AES_BAD_INPUT_DATA                    -0x0021 | 
|  |  | 
|  | /* MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE is deprecated and should not be used. */ | 
|  | /** Feature not available. For example, an unsupported AES key size. */ | 
|  | #define MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE               -0x0023 | 
|  |  | 
|  | /* MBEDTLS_ERR_AES_HW_ACCEL_FAILED is deprecated and should not be used. */ | 
|  | /** AES hardware accelerator failed. */ | 
|  | #define MBEDTLS_ERR_AES_HW_ACCEL_FAILED                   -0x0025 | 
|  |  | 
|  | #if (defined(__ARMCC_VERSION) || defined(_MSC_VER)) && \ | 
|  | !defined(inline) && !defined(__cplusplus) | 
|  | #define inline __inline | 
|  | #endif | 
|  |  | 
|  | #ifdef __cplusplus | 
|  | extern "C" { | 
|  | #endif | 
|  |  | 
|  | #if !defined(MBEDTLS_AES_ALT) | 
|  | // Regular implementation | 
|  | // | 
|  |  | 
|  | /** | 
|  | * \brief The AES context-type definition. | 
|  | */ | 
|  | typedef struct mbedtls_aes_context { | 
|  | int nr;                     /*!< The number of rounds. */ | 
|  | uint32_t *rk;               /*!< AES round keys. */ | 
|  | uint32_t buf[68];           /*!< Unaligned data buffer. This buffer can | 
|  | hold 32 extra Bytes, which can be used for | 
|  | one of the following purposes: | 
|  | <ul><li>Alignment if VIA padlock is | 
|  | used.</li> | 
|  | <li>Simplifying key expansion in the 256-bit | 
|  | case by generating an extra round key. | 
|  | </li></ul> */ | 
|  | } | 
|  | mbedtls_aes_context; | 
|  |  | 
|  | #if defined(MBEDTLS_CIPHER_MODE_XTS) | 
|  | /** | 
|  | * \brief The AES XTS context-type definition. | 
|  | */ | 
|  | typedef struct mbedtls_aes_xts_context { | 
|  | mbedtls_aes_context crypt; /*!< The AES context to use for AES block | 
|  | encryption or decryption. */ | 
|  | mbedtls_aes_context tweak; /*!< The AES context used for tweak | 
|  | computation. */ | 
|  | } mbedtls_aes_xts_context; | 
|  | #endif /* MBEDTLS_CIPHER_MODE_XTS */ | 
|  |  | 
|  | #else  /* MBEDTLS_AES_ALT */ | 
|  | #include "aes_alt.h" | 
|  | #endif /* MBEDTLS_AES_ALT */ | 
|  |  | 
|  | /** | 
|  | * \brief          This function initializes the specified AES context. | 
|  | * | 
|  | *                 It must be the first API called before using | 
|  | *                 the context. | 
|  | * | 
|  | * \param ctx      The AES context to initialize. This must not be \c NULL. | 
|  | */ | 
|  | void mbedtls_aes_init(mbedtls_aes_context *ctx); | 
|  |  | 
|  | /** | 
|  | * \brief          This function releases and clears the specified AES context. | 
|  | * | 
|  | * \param ctx      The AES context to clear. | 
|  | *                 If this is \c NULL, this function does nothing. | 
|  | *                 Otherwise, the context must have been at least initialized. | 
|  | */ | 
|  | void mbedtls_aes_free(mbedtls_aes_context *ctx); | 
|  |  | 
|  | #if defined(MBEDTLS_CIPHER_MODE_XTS) | 
|  | /** | 
|  | * \brief          This function initializes the specified AES XTS context. | 
|  | * | 
|  | *                 It must be the first API called before using | 
|  | *                 the context. | 
|  | * | 
|  | * \param ctx      The AES XTS context to initialize. This must not be \c NULL. | 
|  | */ | 
|  | void mbedtls_aes_xts_init(mbedtls_aes_xts_context *ctx); | 
|  |  | 
|  | /** | 
|  | * \brief          This function releases and clears the specified AES XTS context. | 
|  | * | 
|  | * \param ctx      The AES XTS context to clear. | 
|  | *                 If this is \c NULL, this function does nothing. | 
|  | *                 Otherwise, the context must have been at least initialized. | 
|  | */ | 
|  | void mbedtls_aes_xts_free(mbedtls_aes_xts_context *ctx); | 
|  | #endif /* MBEDTLS_CIPHER_MODE_XTS */ | 
|  |  | 
|  | /** | 
|  | * \brief          This function sets the encryption key. | 
|  | * | 
|  | * \param ctx      The AES context to which the key should be bound. | 
|  | *                 It must be initialized. | 
|  | * \param key      The encryption key. | 
|  | *                 This must be a readable buffer of size \p keybits bits. | 
|  | * \param keybits  The size of data passed in bits. Valid options are: | 
|  | *                 <ul><li>128 bits</li> | 
|  | *                 <li>192 bits</li> | 
|  | *                 <li>256 bits</li></ul> | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_aes_setkey_enc(mbedtls_aes_context *ctx, const unsigned char *key, | 
|  | unsigned int keybits); | 
|  |  | 
|  | /** | 
|  | * \brief          This function sets the decryption key. | 
|  | * | 
|  | * \param ctx      The AES context to which the key should be bound. | 
|  | *                 It must be initialized. | 
|  | * \param key      The decryption key. | 
|  | *                 This must be a readable buffer of size \p keybits bits. | 
|  | * \param keybits  The size of data passed. Valid options are: | 
|  | *                 <ul><li>128 bits</li> | 
|  | *                 <li>192 bits</li> | 
|  | *                 <li>256 bits</li></ul> | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_aes_setkey_dec(mbedtls_aes_context *ctx, const unsigned char *key, | 
|  | unsigned int keybits); | 
|  |  | 
|  | #if defined(MBEDTLS_CIPHER_MODE_XTS) | 
|  | /** | 
|  | * \brief          This function prepares an XTS context for encryption and | 
|  | *                 sets the encryption key. | 
|  | * | 
|  | * \param ctx      The AES XTS context to which the key should be bound. | 
|  | *                 It must be initialized. | 
|  | * \param key      The encryption key. This is comprised of the XTS key1 | 
|  | *                 concatenated with the XTS key2. | 
|  | *                 This must be a readable buffer of size \p keybits bits. | 
|  | * \param keybits  The size of \p key passed in bits. Valid options are: | 
|  | *                 <ul><li>256 bits (each of key1 and key2 is a 128-bit key)</li> | 
|  | *                 <li>512 bits (each of key1 and key2 is a 256-bit key)</li></ul> | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_aes_xts_setkey_enc(mbedtls_aes_xts_context *ctx, | 
|  | const unsigned char *key, | 
|  | unsigned int keybits); | 
|  |  | 
|  | /** | 
|  | * \brief          This function prepares an XTS context for decryption and | 
|  | *                 sets the decryption key. | 
|  | * | 
|  | * \param ctx      The AES XTS context to which the key should be bound. | 
|  | *                 It must be initialized. | 
|  | * \param key      The decryption key. This is comprised of the XTS key1 | 
|  | *                 concatenated with the XTS key2. | 
|  | *                 This must be a readable buffer of size \p keybits bits. | 
|  | * \param keybits  The size of \p key passed in bits. Valid options are: | 
|  | *                 <ul><li>256 bits (each of key1 and key2 is a 128-bit key)</li> | 
|  | *                 <li>512 bits (each of key1 and key2 is a 256-bit key)</li></ul> | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | * \return         #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_aes_xts_setkey_dec(mbedtls_aes_xts_context *ctx, | 
|  | const unsigned char *key, | 
|  | unsigned int keybits); | 
|  | #endif /* MBEDTLS_CIPHER_MODE_XTS */ | 
|  |  | 
|  | /** | 
|  | * \brief          This function performs an AES single-block encryption or | 
|  | *                 decryption operation. | 
|  | * | 
|  | *                 It performs the operation defined in the \p mode parameter | 
|  | *                 (encrypt or decrypt), on the input data buffer defined in | 
|  | *                 the \p input parameter. | 
|  | * | 
|  | *                 mbedtls_aes_init(), and either mbedtls_aes_setkey_enc() or | 
|  | *                 mbedtls_aes_setkey_dec() must be called before the first | 
|  | *                 call to this API with the same context. | 
|  | * | 
|  | * \param ctx      The AES context to use for encryption or decryption. | 
|  | *                 It must be initialized and bound to a key. | 
|  | * \param mode     The AES operation: #MBEDTLS_AES_ENCRYPT or | 
|  | *                 #MBEDTLS_AES_DECRYPT. | 
|  | * \param input    The buffer holding the input data. | 
|  | *                 It must be readable and at least \c 16 Bytes long. | 
|  | * \param output   The buffer where the output data will be written. | 
|  | *                 It must be writeable and at least \c 16 Bytes long. | 
|  |  | 
|  | * \return         \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | 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  This function performs an AES-CBC encryption or decryption operation | 
|  | *         on full blocks. | 
|  | * | 
|  | *         It performs the operation defined in the \p mode | 
|  | *         parameter (encrypt/decrypt), on the input data buffer defined in | 
|  | *         the \p input parameter. | 
|  | * | 
|  | *         It can be called as many times as needed, until all the input | 
|  | *         data is processed. mbedtls_aes_init(), and either | 
|  | *         mbedtls_aes_setkey_enc() or mbedtls_aes_setkey_dec() must be called | 
|  | *         before the first call to this API with the same context. | 
|  | * | 
|  | * \note   This function operates on full blocks, that is, the input size | 
|  | *         must be a multiple of the AES block size of \c 16 Bytes. | 
|  | * | 
|  | * \note   Upon exit, the content of the IV is updated so that you can | 
|  | *         call the same function again on the next | 
|  | *         block(s) of data and get the same result as if it was | 
|  | *         encrypted in one call. This allows a "streaming" usage. | 
|  | *         If you need to retain the contents of the IV, you should | 
|  | *         either save it manually or use the cipher module instead. | 
|  | * | 
|  | * | 
|  | * \param ctx      The AES context to use for encryption or decryption. | 
|  | *                 It must be initialized and bound to a key. | 
|  | * \param mode     The AES operation: #MBEDTLS_AES_ENCRYPT or | 
|  | *                 #MBEDTLS_AES_DECRYPT. | 
|  | * \param length   The length of the input data in Bytes. This must be a | 
|  | *                 multiple of the block size (\c 16 Bytes). | 
|  | * \param iv       Initialization vector (updated after use). | 
|  | *                 It must be a readable and writeable buffer of \c 16 Bytes. | 
|  | * \param input    The buffer holding the input data. | 
|  | *                 It must be readable and of size \p length Bytes. | 
|  | * \param output   The buffer holding the output data. | 
|  | *                 It must be writeable and of size \p length Bytes. | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | * \return         #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH | 
|  | *                 on failure. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | 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_XTS) | 
|  | /** | 
|  | * \brief      This function performs an AES-XTS encryption or decryption | 
|  | *             operation for an entire XTS data unit. | 
|  | * | 
|  | *             AES-XTS encrypts or decrypts blocks based on their location as | 
|  | *             defined by a data unit number. The data unit number must be | 
|  | *             provided by \p data_unit. | 
|  | * | 
|  | *             NIST SP 800-38E limits the maximum size of a data unit to 2^20 | 
|  | *             AES blocks. If the data unit is larger than this, this function | 
|  | *             returns #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH. | 
|  | * | 
|  | * \param ctx          The AES XTS context to use for AES XTS operations. | 
|  | *                     It must be initialized and bound to a key. | 
|  | * \param mode         The AES operation: #MBEDTLS_AES_ENCRYPT or | 
|  | *                     #MBEDTLS_AES_DECRYPT. | 
|  | * \param length       The length of a data unit in Bytes. This can be any | 
|  | *                     length between 16 bytes and 2^24 bytes inclusive | 
|  | *                     (between 1 and 2^20 block cipher blocks). | 
|  | * \param data_unit    The address of the data unit encoded as an array of 16 | 
|  | *                     bytes in little-endian format. For disk encryption, this | 
|  | *                     is typically the index of the block device sector that | 
|  | *                     contains the data. | 
|  | * \param input        The buffer holding the input data (which is an entire | 
|  | *                     data unit). This function reads \p length Bytes from \p | 
|  | *                     input. | 
|  | * \param output       The buffer holding the output data (which is an entire | 
|  | *                     data unit). This function writes \p length Bytes to \p | 
|  | *                     output. | 
|  | * | 
|  | * \return             \c 0 on success. | 
|  | * \return             #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH if \p length is | 
|  | *                     smaller than an AES block in size (16 Bytes) or if \p | 
|  | *                     length is larger than 2^20 blocks (16 MiB). | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_aes_crypt_xts(mbedtls_aes_xts_context *ctx, | 
|  | int mode, | 
|  | size_t length, | 
|  | const unsigned char data_unit[16], | 
|  | const unsigned char *input, | 
|  | unsigned char *output); | 
|  | #endif /* MBEDTLS_CIPHER_MODE_XTS */ | 
|  |  | 
|  | #if defined(MBEDTLS_CIPHER_MODE_CFB) | 
|  | /** | 
|  | * \brief This function performs an AES-CFB128 encryption or decryption | 
|  | *        operation. | 
|  | * | 
|  | *        It performs the operation defined in the \p mode | 
|  | *        parameter (encrypt or decrypt), on the input data buffer | 
|  | *        defined in the \p input parameter. | 
|  | * | 
|  | *        For CFB, you must set up the context with mbedtls_aes_setkey_enc(), | 
|  | *        regardless of whether you are performing an encryption or decryption | 
|  | *        operation, that is, regardless of the \p mode parameter. This is | 
|  | *        because CFB mode uses the same key schedule for encryption and | 
|  | *        decryption. | 
|  | * | 
|  | * \note  Upon exit, the content of the IV is updated so that you can | 
|  | *        call the same function again on the next | 
|  | *        block(s) of data and get the same result as if it was | 
|  | *        encrypted in one call. This allows a "streaming" usage. | 
|  | *        If you need to retain the contents of the | 
|  | *        IV, you must either save it manually or use the cipher | 
|  | *        module instead. | 
|  | * | 
|  | * | 
|  | * \param ctx      The AES context to use for encryption or decryption. | 
|  | *                 It must be initialized and bound to a key. | 
|  | * \param mode     The AES operation: #MBEDTLS_AES_ENCRYPT or | 
|  | *                 #MBEDTLS_AES_DECRYPT. | 
|  | * \param length   The length of the input data in Bytes. | 
|  | * \param iv_off   The offset in IV (updated after use). | 
|  | *                 It must point to a valid \c size_t. | 
|  | * \param iv       The initialization vector (updated after use). | 
|  | *                 It must be a readable and writeable buffer of \c 16 Bytes. | 
|  | * \param input    The buffer holding the input data. | 
|  | *                 It must be readable and of size \p length Bytes. | 
|  | * \param output   The buffer holding the output data. | 
|  | *                 It must be writeable and of size \p length Bytes. | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | 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 This function performs an AES-CFB8 encryption or decryption | 
|  | *        operation. | 
|  | * | 
|  | *        It performs the operation defined in the \p mode | 
|  | *        parameter (encrypt/decrypt), on the input data buffer defined | 
|  | *        in the \p input parameter. | 
|  | * | 
|  | *        Due to the nature of CFB, you must use the same key schedule for | 
|  | *        both encryption and decryption operations. Therefore, you must | 
|  | *        use the 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 same function again on the next | 
|  | *        block(s) of data and get the same result as if it was | 
|  | *        encrypted in one call. This allows a "streaming" usage. | 
|  | *        If you need to retain the contents of the | 
|  | *        IV, you should either save it manually or use the cipher | 
|  | *        module instead. | 
|  | * | 
|  | * | 
|  | * \param ctx      The AES context to use for encryption or decryption. | 
|  | *                 It must be initialized and bound to a key. | 
|  | * \param mode     The AES operation: #MBEDTLS_AES_ENCRYPT or | 
|  | *                 #MBEDTLS_AES_DECRYPT | 
|  | * \param length   The length of the input data. | 
|  | * \param iv       The initialization vector (updated after use). | 
|  | *                 It must be a readable and writeable buffer of \c 16 Bytes. | 
|  | * \param input    The buffer holding the input data. | 
|  | *                 It must be readable and of size \p length Bytes. | 
|  | * \param output   The buffer holding the output data. | 
|  | *                 It must be writeable and of size \p length Bytes. | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | 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_OFB) | 
|  | /** | 
|  | * \brief       This function performs an AES-OFB (Output Feedback Mode) | 
|  | *              encryption or decryption operation. | 
|  | * | 
|  | *              For OFB, you must set up the context with | 
|  | *              mbedtls_aes_setkey_enc(), regardless of whether you are | 
|  | *              performing an encryption or decryption operation. This is | 
|  | *              because OFB mode uses the same key schedule for encryption and | 
|  | *              decryption. | 
|  | * | 
|  | *              The OFB operation is identical for encryption or decryption, | 
|  | *              therefore no operation mode needs to be specified. | 
|  | * | 
|  | * \note        Upon exit, the content of iv, the Initialisation Vector, is | 
|  | *              updated so that you can call the same function again on the next | 
|  | *              block(s) of data and get the same result as if it was encrypted | 
|  | *              in one call. This allows a "streaming" usage, by initialising | 
|  | *              iv_off to 0 before the first call, and preserving its value | 
|  | *              between calls. | 
|  | * | 
|  | *              For non-streaming use, the iv should be initialised on each call | 
|  | *              to a unique value, and iv_off set to 0 on each call. | 
|  | * | 
|  | *              If you need to retain the contents of the initialisation vector, | 
|  | *              you must either save it manually or use the cipher module | 
|  | *              instead. | 
|  | * | 
|  | * \warning     For the OFB mode, the initialisation vector must be unique | 
|  | *              every encryption operation. Reuse of an initialisation vector | 
|  | *              will compromise security. | 
|  | * | 
|  | * \param ctx      The AES context to use for encryption or decryption. | 
|  | *                 It must be initialized and bound to a key. | 
|  | * \param length   The length of the input data. | 
|  | * \param iv_off   The offset in IV (updated after use). | 
|  | *                 It must point to a valid \c size_t. | 
|  | * \param iv       The initialization vector (updated after use). | 
|  | *                 It must be a readable and writeable buffer of \c 16 Bytes. | 
|  | * \param input    The buffer holding the input data. | 
|  | *                 It must be readable and of size \p length Bytes. | 
|  | * \param output   The buffer holding the output data. | 
|  | *                 It must be writeable and of size \p length Bytes. | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_aes_crypt_ofb(mbedtls_aes_context *ctx, | 
|  | size_t length, | 
|  | size_t *iv_off, | 
|  | unsigned char iv[16], | 
|  | const unsigned char *input, | 
|  | unsigned char *output); | 
|  |  | 
|  | #endif /* MBEDTLS_CIPHER_MODE_OFB */ | 
|  |  | 
|  | #if defined(MBEDTLS_CIPHER_MODE_CTR) | 
|  | /** | 
|  | * \brief      This function performs an AES-CTR encryption or decryption | 
|  | *             operation. | 
|  | * | 
|  | *             Due to the nature of CTR, you must use the same key schedule | 
|  | *             for both encryption and decryption operations. Therefore, you | 
|  | *             must use the context initialized with mbedtls_aes_setkey_enc() | 
|  | *             for both #MBEDTLS_AES_ENCRYPT and #MBEDTLS_AES_DECRYPT. | 
|  | * | 
|  | * \warning    You must never reuse a nonce value with the same key. Doing so | 
|  | *             would void the encryption for the two messages encrypted with | 
|  | *             the same nonce and key. | 
|  | * | 
|  | *             There are two common strategies for managing nonces with CTR: | 
|  | * | 
|  | *             1. You can handle everything as a single message processed over | 
|  | *             successive calls to this function. In that case, you want to | 
|  | *             set \p nonce_counter and \p nc_off to 0 for the first call, and | 
|  | *             then preserve the values of \p nonce_counter, \p nc_off and \p | 
|  | *             stream_block across calls to this function as they will be | 
|  | *             updated by this function. | 
|  | * | 
|  | *             With this strategy, you must not encrypt more than 2**128 | 
|  | *             blocks of data with the same key. | 
|  | * | 
|  | *             2. You can encrypt separate messages by dividing the \p | 
|  | *             nonce_counter buffer in two areas: the first one used for a | 
|  | *             per-message nonce, handled by yourself, and the second one | 
|  | *             updated by this function internally. | 
|  | * | 
|  | *             For example, you might reserve the first 12 bytes for the | 
|  | *             per-message nonce, and the last 4 bytes for internal use. In that | 
|  | *             case, before calling this function on a new message you need to | 
|  | *             set the first 12 bytes of \p nonce_counter to your chosen nonce | 
|  | *             value, the last 4 to 0, and \p nc_off to 0 (which will cause \p | 
|  | *             stream_block to be ignored). That way, you can encrypt at most | 
|  | *             2**96 messages of up to 2**32 blocks each with the same key. | 
|  | * | 
|  | *             The per-message nonce (or information sufficient to reconstruct | 
|  | *             it) needs to be communicated with the ciphertext and must be unique. | 
|  | *             The recommended way to ensure uniqueness is to use a message | 
|  | *             counter. An alternative is to generate random nonces, but this | 
|  | *             limits the number of messages that can be securely encrypted: | 
|  | *             for example, with 96-bit random nonces, you should not encrypt | 
|  | *             more than 2**32 messages with the same key. | 
|  | * | 
|  | *             Note that for both strategies, sizes are measured in blocks and | 
|  | *             that an AES block is 16 bytes. | 
|  | * | 
|  | * \warning    Upon return, \p stream_block contains sensitive data. Its | 
|  | *             content must not be written to insecure storage and should be | 
|  | *             securely discarded as soon as it's no longer needed. | 
|  | * | 
|  | * \param ctx              The AES context to use for encryption or decryption. | 
|  | *                         It must be initialized and bound to a key. | 
|  | * \param length           The length of the input data. | 
|  | * \param nc_off           The offset in the current \p stream_block, for | 
|  | *                         resuming within the current cipher stream. The | 
|  | *                         offset pointer should be 0 at the start of a stream. | 
|  | *                         It must point to a valid \c size_t. | 
|  | * \param nonce_counter    The 128-bit nonce and counter. | 
|  | *                         It must be a readable-writeable buffer of \c 16 Bytes. | 
|  | * \param stream_block     The saved stream block for resuming. This is | 
|  | *                         overwritten by the function. | 
|  | *                         It must be a readable-writeable buffer of \c 16 Bytes. | 
|  | * \param input            The buffer holding the input data. | 
|  | *                         It must be readable and of size \p length Bytes. | 
|  | * \param output           The buffer holding the output data. | 
|  | *                         It must be writeable and of size \p length Bytes. | 
|  | * | 
|  | * \return                 \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | 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. This is only | 
|  | *                  exposed to allow overriding it using | 
|  | *                  \c MBEDTLS_AES_ENCRYPT_ALT. | 
|  | * | 
|  | * \param ctx       The AES context to use for encryption. | 
|  | * \param input     The plaintext block. | 
|  | * \param output    The output (ciphertext) block. | 
|  | * | 
|  | * \return          \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_internal_aes_encrypt(mbedtls_aes_context *ctx, | 
|  | const unsigned char input[16], | 
|  | unsigned char output[16]); | 
|  |  | 
|  | /** | 
|  | * \brief           Internal AES block decryption function. This is only | 
|  | *                  exposed to allow overriding it using see | 
|  | *                  \c MBEDTLS_AES_DECRYPT_ALT. | 
|  | * | 
|  | * \param ctx       The AES context to use for decryption. | 
|  | * \param input     The ciphertext block. | 
|  | * \param output    The output (plaintext) block. | 
|  | * | 
|  | * \return          \c 0 on success. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_TYPICAL | 
|  | int mbedtls_internal_aes_decrypt(mbedtls_aes_context *ctx, | 
|  | const unsigned char input[16], | 
|  | unsigned char output[16]); | 
|  |  | 
|  | #if !defined(MBEDTLS_DEPRECATED_REMOVED) | 
|  | #if defined(MBEDTLS_DEPRECATED_WARNING) | 
|  | #define MBEDTLS_DEPRECATED      __attribute__((deprecated)) | 
|  | #else | 
|  | #define MBEDTLS_DEPRECATED | 
|  | #endif | 
|  | /** | 
|  | * \brief           Deprecated internal AES block encryption function | 
|  | *                  without return value. | 
|  | * | 
|  | * \deprecated      Superseded by mbedtls_internal_aes_encrypt() | 
|  | * | 
|  | * \param ctx       The AES context to use for encryption. | 
|  | * \param input     Plaintext block. | 
|  | * \param output    Output (ciphertext) block. | 
|  | */ | 
|  | MBEDTLS_DEPRECATED void mbedtls_aes_encrypt(mbedtls_aes_context *ctx, | 
|  | const unsigned char input[16], | 
|  | unsigned char output[16]); | 
|  |  | 
|  | /** | 
|  | * \brief           Deprecated internal AES block decryption function | 
|  | *                  without return value. | 
|  | * | 
|  | * \deprecated      Superseded by mbedtls_internal_aes_decrypt() | 
|  | * | 
|  | * \param ctx       The AES context to use for decryption. | 
|  | * \param input     Ciphertext block. | 
|  | * \param output    Output (plaintext) block. | 
|  | */ | 
|  | MBEDTLS_DEPRECATED void mbedtls_aes_decrypt(mbedtls_aes_context *ctx, | 
|  | const unsigned char input[16], | 
|  | unsigned char output[16]); | 
|  |  | 
|  | #undef MBEDTLS_DEPRECATED | 
|  | #endif /* !MBEDTLS_DEPRECATED_REMOVED */ | 
|  |  | 
|  |  | 
|  | #if defined(MBEDTLS_SELF_TEST) | 
|  | /** | 
|  | * \brief          Checkup routine. | 
|  | * | 
|  | * \return         \c 0 on success. | 
|  | * \return         \c 1 on failure. | 
|  | */ | 
|  | MBEDTLS_CHECK_RETURN_CRITICAL | 
|  | int mbedtls_aes_self_test(int verbose); | 
|  |  | 
|  | #endif /* MBEDTLS_SELF_TEST */ | 
|  |  | 
|  | #ifdef __cplusplus | 
|  | } | 
|  | #endif | 
|  |  | 
|  | #endif /* aes.h */ |