[398] | 1 | /**
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| 2 | * \file gcm.h
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| 3 | *
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| 4 | * \brief This file contains GCM definitions and functions.
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| 5 | *
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| 6 | * The Galois/Counter Mode (GCM) for 128-bit block ciphers is defined
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| 7 | * in <em>D. McGrew, J. Viega, The Galois/Counter Mode of Operation
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| 8 | * (GCM), Natl. Inst. Stand. Technol.</em>
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| 9 | *
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| 10 | * For more information on GCM, see <em>NIST SP 800-38D: Recommendation for
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| 11 | * Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC</em>.
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| 12 | *
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| 13 | */
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| 14 | /*
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| 15 | * Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
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| 16 | * SPDX-License-Identifier: Apache-2.0
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| 17 | *
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| 18 | * Licensed under the Apache License, Version 2.0 (the "License"); you may
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| 19 | * not use this file except in compliance with the License.
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| 20 | * You may obtain a copy of the License at
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| 21 | *
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| 22 | * http://www.apache.org/licenses/LICENSE-2.0
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| 23 | *
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| 24 | * Unless required by applicable law or agreed to in writing, software
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| 25 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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| 26 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 27 | * See the License for the specific language governing permissions and
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| 28 | * limitations under the License.
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| 29 | *
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| 30 | * This file is part of Mbed TLS (https://tls.mbed.org)
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| 31 | */
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| 32 |
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| 33 | #ifndef MBEDTLS_GCM_H
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| 34 | #define MBEDTLS_GCM_H
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| 35 |
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| 36 | #if !defined(MBEDTLS_CONFIG_FILE)
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| 37 | #include "config.h"
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| 38 | #else
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| 39 | #include MBEDTLS_CONFIG_FILE
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| 40 | #endif
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| 41 |
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| 42 | #include "cipher.h"
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| 43 |
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| 44 | #include <stdint.h>
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| 45 |
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| 46 | #define MBEDTLS_GCM_ENCRYPT 1
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| 47 | #define MBEDTLS_GCM_DECRYPT 0
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| 48 |
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| 49 | #define MBEDTLS_ERR_GCM_AUTH_FAILED -0x0012 /**< Authenticated decryption failed. */
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| 50 |
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| 51 | /* MBEDTLS_ERR_GCM_HW_ACCEL_FAILED is deprecated and should not be used. */
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| 52 | #define MBEDTLS_ERR_GCM_HW_ACCEL_FAILED -0x0013 /**< GCM hardware accelerator failed. */
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| 53 |
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| 54 | #define MBEDTLS_ERR_GCM_BAD_INPUT -0x0014 /**< Bad input parameters to function. */
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| 55 |
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| 56 | #ifdef __cplusplus
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| 57 | extern "C" {
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| 58 | #endif
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| 59 |
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| 60 | #if !defined(MBEDTLS_GCM_ALT)
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| 61 |
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| 62 | /**
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| 63 | * \brief The GCM context structure.
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| 64 | */
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| 65 | typedef struct mbedtls_gcm_context
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| 66 | {
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| 67 | mbedtls_cipher_context_t cipher_ctx; /*!< The cipher context used. */
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| 68 | uint64_t HL[16]; /*!< Precalculated HTable low. */
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| 69 | uint64_t HH[16]; /*!< Precalculated HTable high. */
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| 70 | uint64_t len; /*!< The total length of the encrypted data. */
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| 71 | uint64_t add_len; /*!< The total length of the additional data. */
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| 72 | unsigned char base_ectr[16]; /*!< The first ECTR for tag. */
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| 73 | unsigned char y[16]; /*!< The Y working value. */
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| 74 | unsigned char buf[16]; /*!< The buf working value. */
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| 75 | int mode; /*!< The operation to perform:
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| 76 | #MBEDTLS_GCM_ENCRYPT or
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| 77 | #MBEDTLS_GCM_DECRYPT. */
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| 78 | }
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| 79 | mbedtls_gcm_context;
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| 80 |
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| 81 | #else /* !MBEDTLS_GCM_ALT */
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| 82 | #include "gcm_alt.h"
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| 83 | #endif /* !MBEDTLS_GCM_ALT */
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| 84 |
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| 85 | /**
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| 86 | * \brief This function initializes the specified GCM context,
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| 87 | * to make references valid, and prepares the context
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| 88 | * for mbedtls_gcm_setkey() or mbedtls_gcm_free().
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| 89 | *
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| 90 | * The function does not bind the GCM context to a particular
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| 91 | * cipher, nor set the key. For this purpose, use
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| 92 | * mbedtls_gcm_setkey().
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| 93 | *
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| 94 | * \param ctx The GCM context to initialize. This must not be \c NULL.
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| 95 | */
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| 96 | void mbedtls_gcm_init( mbedtls_gcm_context *ctx );
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| 97 |
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| 98 | /**
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| 99 | * \brief This function associates a GCM context with a
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| 100 | * cipher algorithm and a key.
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| 101 | *
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| 102 | * \param ctx The GCM context. This must be initialized.
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| 103 | * \param cipher The 128-bit block cipher to use.
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| 104 | * \param key The encryption key. This must be a readable buffer of at
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| 105 | * least \p keybits bits.
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| 106 | * \param keybits The key size in bits. Valid options are:
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| 107 | * <ul><li>128 bits</li>
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| 108 | * <li>192 bits</li>
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| 109 | * <li>256 bits</li></ul>
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| 110 | *
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| 111 | * \return \c 0 on success.
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| 112 | * \return A cipher-specific error code on failure.
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| 113 | */
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| 114 | int mbedtls_gcm_setkey( mbedtls_gcm_context *ctx,
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| 115 | mbedtls_cipher_id_t cipher,
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| 116 | const unsigned char *key,
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| 117 | unsigned int keybits );
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| 118 |
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| 119 | /**
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| 120 | * \brief This function performs GCM encryption or decryption of a buffer.
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| 121 | *
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| 122 | * \note For encryption, the output buffer can be the same as the
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| 123 | * input buffer. For decryption, the output buffer cannot be
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| 124 | * the same as input buffer. If the buffers overlap, the output
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| 125 | * buffer must trail at least 8 Bytes behind the input buffer.
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| 126 | *
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| 127 | * \warning When this function performs a decryption, it outputs the
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| 128 | * authentication tag and does not verify that the data is
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| 129 | * authentic. You should use this function to perform encryption
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| 130 | * only. For decryption, use mbedtls_gcm_auth_decrypt() instead.
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| 131 | *
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| 132 | * \param ctx The GCM context to use for encryption or decryption. This
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| 133 | * must be initialized.
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| 134 | * \param mode The operation to perform:
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| 135 | * - #MBEDTLS_GCM_ENCRYPT to perform authenticated encryption.
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| 136 | * The ciphertext is written to \p output and the
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| 137 | * authentication tag is written to \p tag.
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| 138 | * - #MBEDTLS_GCM_DECRYPT to perform decryption.
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| 139 | * The plaintext is written to \p output and the
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| 140 | * authentication tag is written to \p tag.
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| 141 | * Note that this mode is not recommended, because it does
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| 142 | * not verify the authenticity of the data. For this reason,
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| 143 | * you should use mbedtls_gcm_auth_decrypt() instead of
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| 144 | * calling this function in decryption mode.
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| 145 | * \param length The length of the input data, which is equal to the length
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| 146 | * of the output data.
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| 147 | * \param iv The initialization vector. This must be a readable buffer of
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| 148 | * at least \p iv_len Bytes.
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| 149 | * \param iv_len The length of the IV.
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| 150 | * \param add The buffer holding the additional data. This must be of at
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| 151 | * least that size in Bytes.
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| 152 | * \param add_len The length of the additional data.
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| 153 | * \param input The buffer holding the input data. If \p length is greater
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| 154 | * than zero, this must be a readable buffer of at least that
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| 155 | * size in Bytes.
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| 156 | * \param output The buffer for holding the output data. If \p length is greater
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| 157 | * than zero, this must be a writable buffer of at least that
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| 158 | * size in Bytes.
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| 159 | * \param tag_len The length of the tag to generate.
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| 160 | * \param tag The buffer for holding the tag. This must be a readable
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| 161 | * buffer of at least \p tag_len Bytes.
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| 162 | *
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| 163 | * \return \c 0 if the encryption or decryption was performed
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| 164 | * successfully. Note that in #MBEDTLS_GCM_DECRYPT mode,
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| 165 | * this does not indicate that the data is authentic.
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| 166 | * \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths or pointers are
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| 167 | * not valid or a cipher-specific error code if the encryption
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| 168 | * or decryption failed.
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| 169 | */
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| 170 | int mbedtls_gcm_crypt_and_tag( mbedtls_gcm_context *ctx,
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| 171 | int mode,
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| 172 | size_t length,
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| 173 | const unsigned char *iv,
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| 174 | size_t iv_len,
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| 175 | const unsigned char *add,
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| 176 | size_t add_len,
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| 177 | const unsigned char *input,
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| 178 | unsigned char *output,
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| 179 | size_t tag_len,
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| 180 | unsigned char *tag );
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| 181 |
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| 182 | /**
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| 183 | * \brief This function performs a GCM authenticated decryption of a
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| 184 | * buffer.
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| 185 | *
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| 186 | * \note For decryption, the output buffer cannot be the same as
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| 187 | * input buffer. If the buffers overlap, the output buffer
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| 188 | * must trail at least 8 Bytes behind the input buffer.
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| 189 | *
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| 190 | * \param ctx The GCM context. This must be initialized.
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| 191 | * \param length The length of the ciphertext to decrypt, which is also
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| 192 | * the length of the decrypted plaintext.
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| 193 | * \param iv The initialization vector. This must be a readable buffer
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| 194 | * of at least \p iv_len Bytes.
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| 195 | * \param iv_len The length of the IV.
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| 196 | * \param add The buffer holding the additional data. This must be of at
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| 197 | * least that size in Bytes.
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| 198 | * \param add_len The length of the additional data.
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| 199 | * \param tag The buffer holding the tag to verify. This must be a
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| 200 | * readable buffer of at least \p tag_len Bytes.
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| 201 | * \param tag_len The length of the tag to verify.
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| 202 | * \param input The buffer holding the ciphertext. If \p length is greater
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| 203 | * than zero, this must be a readable buffer of at least that
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| 204 | * size.
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| 205 | * \param output The buffer for holding the decrypted plaintext. If \p length
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| 206 | * is greater than zero, this must be a writable buffer of at
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| 207 | * least that size.
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| 208 | *
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| 209 | * \return \c 0 if successful and authenticated.
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| 210 | * \return #MBEDTLS_ERR_GCM_AUTH_FAILED if the tag does not match.
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| 211 | * \return #MBEDTLS_ERR_GCM_BAD_INPUT if the lengths or pointers are
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| 212 | * not valid or a cipher-specific error code if the decryption
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| 213 | * failed.
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| 214 | */
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| 215 | int mbedtls_gcm_auth_decrypt( mbedtls_gcm_context *ctx,
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| 216 | size_t length,
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| 217 | const unsigned char *iv,
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| 218 | size_t iv_len,
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| 219 | const unsigned char *add,
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| 220 | size_t add_len,
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| 221 | const unsigned char *tag,
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| 222 | size_t tag_len,
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| 223 | const unsigned char *input,
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| 224 | unsigned char *output );
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| 225 |
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| 226 | /**
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| 227 | * \brief This function starts a GCM encryption or decryption
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| 228 | * operation.
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| 229 | *
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| 230 | * \param ctx The GCM context. This must be initialized.
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| 231 | * \param mode The operation to perform: #MBEDTLS_GCM_ENCRYPT or
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| 232 | * #MBEDTLS_GCM_DECRYPT.
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| 233 | * \param iv The initialization vector. This must be a readable buffer of
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| 234 | * at least \p iv_len Bytes.
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| 235 | * \param iv_len The length of the IV.
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| 236 | * \param add The buffer holding the additional data, or \c NULL
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| 237 | * if \p add_len is \c 0.
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| 238 | * \param add_len The length of the additional data. If \c 0,
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| 239 | * \p add may be \c NULL.
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| 240 | *
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| 241 | * \return \c 0 on success.
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| 242 | */
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| 243 | int mbedtls_gcm_starts( mbedtls_gcm_context *ctx,
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| 244 | int mode,
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| 245 | const unsigned char *iv,
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| 246 | size_t iv_len,
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| 247 | const unsigned char *add,
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| 248 | size_t add_len );
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| 249 |
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| 250 | /**
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| 251 | * \brief This function feeds an input buffer into an ongoing GCM
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| 252 | * encryption or decryption operation.
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| 253 | *
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| 254 | * ` The function expects input to be a multiple of 16
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| 255 | * Bytes. Only the last call before calling
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| 256 | * mbedtls_gcm_finish() can be less than 16 Bytes.
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| 257 | *
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| 258 | * \note For decryption, the output buffer cannot be the same as
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| 259 | * input buffer. If the buffers overlap, the output buffer
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| 260 | * must trail at least 8 Bytes behind the input buffer.
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| 261 | *
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| 262 | * \param ctx The GCM context. This must be initialized.
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| 263 | * \param length The length of the input data. This must be a multiple of
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| 264 | * 16 except in the last call before mbedtls_gcm_finish().
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| 265 | * \param input The buffer holding the input data. If \p length is greater
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| 266 | * than zero, this must be a readable buffer of at least that
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| 267 | * size in Bytes.
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| 268 | * \param output The buffer for holding the output data. If \p length is
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| 269 | * greater than zero, this must be a writable buffer of at
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| 270 | * least that size in Bytes.
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| 271 | *
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| 272 | * \return \c 0 on success.
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| 273 | * \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
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| 274 | */
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| 275 | int mbedtls_gcm_update( mbedtls_gcm_context *ctx,
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| 276 | size_t length,
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| 277 | const unsigned char *input,
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| 278 | unsigned char *output );
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| 279 |
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| 280 | /**
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| 281 | * \brief This function finishes the GCM operation and generates
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| 282 | * the authentication tag.
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| 283 | *
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| 284 | * It wraps up the GCM stream, and generates the
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| 285 | * tag. The tag can have a maximum length of 16 Bytes.
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| 286 | *
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| 287 | * \param ctx The GCM context. This must be initialized.
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| 288 | * \param tag The buffer for holding the tag. This must be a readable
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| 289 | * buffer of at least \p tag_len Bytes.
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| 290 | * \param tag_len The length of the tag to generate. This must be at least
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| 291 | * four.
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| 292 | *
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| 293 | * \return \c 0 on success.
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| 294 | * \return #MBEDTLS_ERR_GCM_BAD_INPUT on failure.
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| 295 | */
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| 296 | int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
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| 297 | unsigned char *tag,
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| 298 | size_t tag_len );
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| 299 |
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| 300 | /**
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| 301 | * \brief This function clears a GCM context and the underlying
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| 302 | * cipher sub-context.
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| 303 | *
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| 304 | * \param ctx The GCM context to clear. If this is \c NULL, the call has
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| 305 | * no effect. Otherwise, this must be initialized.
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| 306 | */
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| 307 | void mbedtls_gcm_free( mbedtls_gcm_context *ctx );
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| 308 |
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| 309 | #if defined(MBEDTLS_SELF_TEST)
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| 310 |
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| 311 | /**
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| 312 | * \brief The GCM checkup routine.
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| 313 | *
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| 314 | * \return \c 0 on success.
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| 315 | * \return \c 1 on failure.
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| 316 | */
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| 317 | int mbedtls_gcm_self_test( int verbose );
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| 318 |
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| 319 | #endif /* MBEDTLS_SELF_TEST */
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| 320 |
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| 321 | #ifdef __cplusplus
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| 322 | }
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| 323 | #endif
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| 324 |
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| 325 |
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| 326 | #endif /* gcm.h */
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