/** * \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 #include "mbedtls/private_access.h" #include "mbedtls/build_info.h" #include "mbedtls/platform_util.h" #include <stddef.h> #include <stdint.h> /* padlock.c and aesni.c rely on these values! */ #define MBEDTLS_AES_ENCRYPT … #define MBEDTLS_AES_DECRYPT … /* Error codes in range 0x0020-0x0022 */ /** Invalid key length. */ #define MBEDTLS_ERR_AES_INVALID_KEY_LENGTH … /** Invalid data input length. */ #define MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH … /* Error codes in range 0x0021-0x0025 */ /** Invalid input data. */ #define MBEDTLS_ERR_AES_BAD_INPUT_DATA … #ifdef __cplusplus extern "C" { #endif #if !defined(MBEDTLS_AES_ALT) // Regular implementation // /** * \brief The AES context-type definition. */ mbedtls_aes_context; #if defined(MBEDTLS_CIPHER_MODE_XTS) /** * \brief The AES XTS context-type definition. */ 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); #if !defined(MBEDTLS_BLOCK_CIPHER_NO_DECRYPT) /** * \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); #endif /* !MBEDTLS_BLOCK_CIPHER_NO_DECRYPT */ #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]); #if !defined(MBEDTLS_BLOCK_CIPHER_NO_DECRYPT) /** * \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]); #endif /* !MBEDTLS_BLOCK_CIPHER_NO_DECRYPT */ #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 */
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