mbedtls/include/mbedtls/gcm.h
Ron Eldor 0559c66ac2 Include configuration file to headers
Add inclusion to configration file in header files,
instead of relying on other header files to include
the configuration file. This issue resolves #1371
2018-12-16 12:22:12 +02:00

296 lines
12 KiB
C

/**
* \file gcm.h
*
* \brief Galois/Counter Mode (GCM) for 128-bit block ciphers, as defined
* in <em>D. McGrew, J. Viega, The Galois/Counter Mode of Operation
* (GCM), Natl. Inst. Stand. Technol.</em>
*
* For more information on GCM, see <em>NIST SP 800-38D: Recommendation for
* Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC</em>.
*
*/
/*
* Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
* 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_GCM_H
#define MBEDTLS_GCM_H
#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif
#include "cipher.h"
#include <stdint.h>
#define MBEDTLS_GCM_ENCRYPT 1
#define MBEDTLS_GCM_DECRYPT 0
#define MBEDTLS_ERR_GCM_AUTH_FAILED -0x0012 /**< Authenticated decryption failed. */
#define MBEDTLS_ERR_GCM_HW_ACCEL_FAILED -0x0013 /**< GCM hardware accelerator failed. */
#define MBEDTLS_ERR_GCM_BAD_INPUT -0x0014 /**< Bad input parameters to function. */
#if !defined(MBEDTLS_GCM_ALT)
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief The GCM context structure.
*/
typedef struct {
mbedtls_cipher_context_t cipher_ctx; /*!< The cipher context used. */
uint64_t HL[16]; /*!< Precalculated HTable low. */
uint64_t HH[16]; /*!< Precalculated HTable high. */
uint64_t len; /*!< The total length of the encrypted data. */
uint64_t add_len; /*!< The total length of the additional data. */
unsigned char base_ectr[16]; /*!< The first ECTR for tag. */
unsigned char y[16]; /*!< The Y working value. */
unsigned char buf[16]; /*!< The buf working value. */
int mode; /*!< The operation to perform:
#MBEDTLS_GCM_ENCRYPT or
#MBEDTLS_GCM_DECRYPT. */
}
mbedtls_gcm_context;
/**
* \brief This function initializes the specified GCM context,
* to make references valid, and prepares the context
* for mbedtls_gcm_setkey() or mbedtls_gcm_free().
*
* The function does not bind the GCM context to a particular
* cipher, nor set the key. For this purpose, use
* mbedtls_gcm_setkey().
*
* \param ctx The GCM context to initialize.
*/
void mbedtls_gcm_init( mbedtls_gcm_context *ctx );
/**
* \brief This function associates a GCM context with a
* cipher algorithm and a key.
*
* \param ctx The GCM context to initialize.
* \param cipher The 128-bit block cipher to use.
* \param key The encryption key.
* \param keybits The key size in bits. Valid options are:
* <ul><li>128 bits</li>
* <li>192 bits</li>
* <li>256 bits</li></ul>
*
* \return \c 0 on success, or a cipher specific error code.
*/
int mbedtls_gcm_setkey( mbedtls_gcm_context *ctx,
mbedtls_cipher_id_t cipher,
const unsigned char *key,
unsigned int keybits );
/**
* \brief This function performs GCM encryption or decryption of a buffer.
*
* \note For encryption, the output buffer can be the same as the input buffer.
* For decryption, the output buffer cannot be the same as input buffer.
* If the buffers overlap, the output buffer must trail at least 8 Bytes
* behind the input buffer.
*
* \warning When this function performs a decryption, it outputs the
* authentication tag and does not verify that the data is
* authentic. You should use this function to perform encryption
* only. For decryption, use mbedtls_gcm_auth_decrypt() instead.
*
* \param ctx The GCM context to use for encryption or decryption.
* \param mode The operation to perform:
* - #MBEDTLS_GCM_ENCRYPT to perform authenticated encryption.
* The ciphertext is written to \p output and the
* authentication tag is written to \p tag.
* - #MBEDTLS_GCM_DECRYPT to perform decryption.
* The plaintext is written to \p output and the
* authentication tag is written to \p tag.
* Note that this mode is not recommended, because it does
* not verify the authenticity of the data. For this reason,
* you should use mbedtls_gcm_auth_decrypt() instead of
* calling this function in decryption mode.
* \param length The length of the input data, which is equal to the length
* of the output data.
* \param iv The initialization vector.
* \param iv_len The length of the IV.
* \param add The buffer holding the additional data.
* \param add_len The length of the additional data.
* \param input The buffer holding the input data. Its size is \b length.
* \param output The buffer for holding the output data. It must have room
* for \b length bytes.
* \param tag_len The length of the tag to generate.
* \param tag The buffer for holding the tag.
*
* \return \c 0 if the encryption or decryption was performed
* successfully. Note that in #MBEDTLS_GCM_DECRYPT mode,
* this does not indicate that the data is authentic.
* \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths are not valid.
* \return #MBEDTLS_ERR_GCM_HW_ACCEL_FAILED or a cipher-specific
* error code if the encryption or decryption failed.
*/
int mbedtls_gcm_crypt_and_tag( mbedtls_gcm_context *ctx,
int mode,
size_t length,
const unsigned char *iv,
size_t iv_len,
const unsigned char *add,
size_t add_len,
const unsigned char *input,
unsigned char *output,
size_t tag_len,
unsigned char *tag );
/**
* \brief This function performs a GCM authenticated decryption of a
* buffer.
*
* \note For decryption, the output buffer cannot be the same as input buffer.
* If the buffers overlap, the output buffer must trail at least 8 Bytes
* behind the input buffer.
*
* \param ctx The GCM context.
* \param length The length of the ciphertext to decrypt, which is also
* the length of the decrypted plaintext.
* \param iv The initialization vector.
* \param iv_len The length of the IV.
* \param add The buffer holding the additional data.
* \param add_len The length of the additional data.
* \param tag The buffer holding the tag to verify.
* \param tag_len The length of the tag to verify.
* \param input The buffer holding the ciphertext. Its size is \b length.
* \param output The buffer for holding the decrypted plaintext. It must
* have room for \b length bytes.
*
* \return \c 0 if successful and authenticated.
* \return #MBEDTLS_ERR_GCM_AUTH_FAILED if the tag does not match.
* \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths are not valid.
* \return #MBEDTLS_ERR_GCM_HW_ACCEL_FAILED or a cipher-specific
* error code if the decryption failed.
*/
int mbedtls_gcm_auth_decrypt( mbedtls_gcm_context *ctx,
size_t length,
const unsigned char *iv,
size_t iv_len,
const unsigned char *add,
size_t add_len,
const unsigned char *tag,
size_t tag_len,
const unsigned char *input,
unsigned char *output );
/**
* \brief This function starts a GCM encryption or decryption
* operation.
*
* \param ctx The GCM context.
* \param mode The operation to perform: #MBEDTLS_GCM_ENCRYPT or
* #MBEDTLS_GCM_DECRYPT.
* \param iv The initialization vector.
* \param iv_len The length of the IV.
* \param add The buffer holding the additional data, or NULL if \p add_len is 0.
* \param add_len The length of the additional data. If 0, \p add is NULL.
*
* \return \c 0 on success.
*/
int mbedtls_gcm_starts( mbedtls_gcm_context *ctx,
int mode,
const unsigned char *iv,
size_t iv_len,
const unsigned char *add,
size_t add_len );
/**
* \brief This function feeds an input buffer into an ongoing GCM
* encryption or decryption operation.
*
* ` The function expects input to be a multiple of 16
* Bytes. Only the last call before calling
* mbedtls_gcm_finish() can be less than 16 Bytes.
*
* \note For decryption, the output buffer cannot be the same as input buffer.
* If the buffers overlap, the output buffer must trail at least 8 Bytes
* behind the input buffer.
*
* \param ctx The GCM context.
* \param length The length of the input data. This must be a multiple of 16 except in the last call before mbedtls_gcm_finish().
* \param input The buffer holding the input data.
* \param output The buffer for holding the output data.
*
* \return \c 0 on success, or #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
*/
int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
size_t length,
const unsigned char *input,
unsigned char *output );
/**
* \brief This function finishes the GCM operation and generates
* the authentication tag.
*
* It wraps up the GCM stream, and generates the
* tag. The tag can have a maximum length of 16 Bytes.
*
* \param ctx The GCM context.
* \param tag The buffer for holding the tag.
* \param tag_len The length of the tag to generate. Must be at least four.
*
* \return \c 0 on success, or #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
*/
int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
unsigned char *tag,
size_t tag_len );
/**
* \brief This function clears a GCM context and the underlying
* cipher sub-context.
*
* \param ctx The GCM context to clear.
*/
void mbedtls_gcm_free( mbedtls_gcm_context *ctx );
#ifdef __cplusplus
}
#endif
#else /* !MBEDTLS_GCM_ALT */
#include "gcm_alt.h"
#endif /* !MBEDTLS_GCM_ALT */
#ifdef __cplusplus
extern "C" {
#endif
/**
* \brief The GCM checkup routine.
*
* \return \c 0 on success, or \c 1 on failure.
*/
int mbedtls_gcm_self_test( int verbose );
#ifdef __cplusplus
}
#endif
#endif /* gcm.h */