238 lines
9.1 KiB
C
238 lines
9.1 KiB
C
/**
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* \brief AES block cipher, ESP32C hardware accelerated version
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* Based on mbedTLS FIPS-197 compliant version.
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*
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* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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* Additions Copyright (C) 2019-2020, Espressif Systems (Shanghai) PTE Ltd
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the "License"); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*
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*/
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#ifndef ESP_GCM_H
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#define ESP_GCM_H
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#include "aes.h"
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#include "mbedtls/cipher.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define MBEDTLS_ERR_GCM_AUTH_FAILED -0x0012 /**< Authenticated decryption failed. */
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#define MBEDTLS_ERR_GCM_BAD_INPUT -0x0014 /**< Bad input parameters to function.*/
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typedef enum {
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ESP_AES_GCM_STATE_INIT,
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ESP_AES_GCM_STATE_UPDATE,
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ESP_AES_GCM_STATE_FINISH
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} esp_aes_gcm_state;
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/**
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* \brief The GCM context structure.
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*/
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typedef struct {
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uint8_t H[16]; /*!< Initial hash value */
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uint8_t ghash[16]; /*!< GHASH value. */
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uint8_t J0[16];
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uint64_t HL[16]; /*!< Precalculated HTable low. */
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uint64_t HH[16]; /*!< Precalculated HTable high. */
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uint8_t ori_j0[16]; /*!< J0 from first iteration. */
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const uint8_t *iv;
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size_t iv_len; /*!< The length of IV. */
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uint64_t aad_len; /*!< The total length of the additional data. */
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size_t data_len;
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int mode;
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const unsigned char *aad; /*!< The additional data. */
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esp_aes_context aes_ctx;
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esp_aes_gcm_state gcm_state;
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} esp_gcm_context;
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/**
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* \brief This function initializes the specified GCM context
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*
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* \param ctx The GCM context to initialize.
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*/
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void esp_aes_gcm_init( esp_gcm_context *ctx);
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/**
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* \brief This function associates a GCM context with a
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* key.
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*
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* \param ctx The GCM context to initialize.
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* \param cipher The 128-bit block cipher to use.
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* \param key The encryption key.
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* \param keybits The key size in bits. Valid options are:
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* <ul><li>128 bits</li>
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* <li>192 bits</li>
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* <li>256 bits</li></ul>
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*
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* \return \c 0 on success.
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* \return A cipher-specific error code on failure.
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*/
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int esp_aes_gcm_setkey( esp_gcm_context *ctx,
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mbedtls_cipher_id_t cipher,
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const unsigned char *key,
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unsigned int keybits );
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/**
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* \brief This function starts a GCM encryption or decryption
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* operation.
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*
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* \param ctx The GCM context.
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* \param mode The operation to perform: #MBEDTLS_GCM_ENCRYPT or
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* #MBEDTLS_GCM_DECRYPT.
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* \param iv The initialization vector.
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* \param iv_len The length of the IV.
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* \param add The buffer holding the additional data, or NULL
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* if \p add_len is 0.
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* \param add_len The length of the additional data. If 0,
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* \p add is NULL.
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*
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* \return \c 0 on success.
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*/
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int esp_aes_gcm_starts( esp_gcm_context *ctx,
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int mode,
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const unsigned char *iv,
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size_t iv_len,
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const unsigned char *aad,
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size_t aad_len );
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/**
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* \brief This function feeds an input buffer into an ongoing GCM
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* encryption or decryption operation.
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*
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* ` The function expects input to be a multiple of 16
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* Bytes. Only the last call before calling
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* mbedtls_gcm_finish() can be less than 16 Bytes.
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*
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* \note For decryption, the output buffer cannot be the same as
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* input buffer. If the buffers overlap, the output buffer
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* must trail at least 8 Bytes behind the input buffer.
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*
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* \param ctx The GCM context.
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* \param length The length of the input data. This must be a multiple of
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* 16 except in the last call before mbedtls_gcm_finish().
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* \param input The buffer holding the input data.
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* \param output The buffer for holding the output data.
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*
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* \return \c 0 on success.
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* \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
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*/
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int esp_aes_gcm_update( esp_gcm_context *ctx,
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size_t length,
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const unsigned char *input,
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unsigned char *output );
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/**
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* \brief This function finishes the GCM operation and generates
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* the authentication tag.
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*
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* It wraps up the GCM stream, and generates the
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* tag. The tag can have a maximum length of 16 Bytes.
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*
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* \param ctx The GCM context.
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* \param tag The buffer for holding the tag.
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* \param tag_len The length of the tag to generate. Must be at least four.
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*
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* \return \c 0 on success.
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* \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
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*/
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int esp_aes_gcm_finish( esp_gcm_context *ctx,
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unsigned char *tag,
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size_t tag_len );
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/**
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* \brief This function clears a GCM context
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*
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* \param ctx The GCM context to clear.
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*/
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void esp_aes_gcm_free( esp_gcm_context *ctx);
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/**
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* \brief This function performs GCM encryption or decryption of a buffer.
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*
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* \note For encryption, the output buffer can be the same as the
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* input buffer. For decryption, the output buffer cannot be
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* the same as input buffer. If the buffers overlap, the output
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* buffer must trail at least 8 Bytes behind the input buffer.
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*
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* \param ctx The GCM context to use for encryption or decryption.
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* \param mode The operation to perform: #MBEDTLS_GCM_ENCRYPT or
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* #MBEDTLS_GCM_DECRYPT.
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* \param length The length of the input data. This must be a multiple of
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* 16 except in the last call before mbedtls_gcm_finish().
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* \param iv The initialization vector.
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* \param iv_len The length of the IV.
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* \param add The buffer holding the additional data.
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* \param add_len The length of the additional data.
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* \param input The buffer holding the input data.
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* \param output The buffer for holding the output data.
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* \param tag_len The length of the tag to generate.
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* \param tag The buffer for holding the tag.
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*
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* \return \c 0 on success.
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*/
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int esp_aes_gcm_crypt_and_tag( esp_gcm_context *ctx,
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int mode,
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size_t length,
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const unsigned char *iv,
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size_t iv_len,
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const unsigned char *add,
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size_t add_len,
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const unsigned char *input,
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unsigned char *output,
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size_t tag_len,
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unsigned char *tag );
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/**
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* \brief This function performs a GCM authenticated decryption of a
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* buffer.
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*
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* \note For decryption, the output buffer cannot be the same as
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* input buffer. If the buffers overlap, the output buffer
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* must trail at least 8 Bytes behind the input buffer.
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*
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* \param ctx The GCM context.
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* \param length The length of the input data. This must be a multiple
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* of 16 except in the last call before mbedtls_gcm_finish().
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* \param iv The initialization vector.
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* \param iv_len The length of the IV.
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* \param add The buffer holding the additional data.
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* \param add_len The length of the additional data.
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* \param tag The buffer holding the tag.
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* \param tag_len The length of the tag.
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* \param input The buffer holding the input data.
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* \param output The buffer for holding the output data.
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*
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* \return 0 if successful and authenticated.
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* \return #MBEDTLS_ERR_GCM_AUTH_FAILED if the tag does not match.
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*/
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int esp_aes_gcm_auth_decrypt( esp_gcm_context *ctx,
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size_t length,
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const unsigned char *iv,
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size_t iv_len,
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const unsigned char *add,
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size_t add_len,
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const unsigned char *tag,
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size_t tag_len,
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const unsigned char *input,
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unsigned char *output );
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#ifdef __cplusplus
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}
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#endif
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#endif /* gcm.h */
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