1 | /**
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2 | * \file aes.h
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3 | *
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4 | * \brief This file contains AES definitions and functions.
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5 | *
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6 | * The Advanced Encryption Standard (AES) specifies a FIPS-approved
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7 | * cryptographic algorithm that can be used to protect electronic
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8 | * data.
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9 | *
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10 | * The AES algorithm is a symmetric block cipher that can
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11 | * encrypt and decrypt information. For more information, see
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12 | * <em>FIPS Publication 197: Advanced Encryption Standard</em> and
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13 | * <em>ISO/IEC 18033-2:2006: Information technology -- Security
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14 | * techniques -- Encryption algorithms -- Part 2: Asymmetric
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15 | * ciphers</em>.
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16 | *
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17 | * The AES-XTS block mode is standardized by NIST SP 800-38E
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18 | * <https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-38e.pdf>
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19 | * and described in detail by IEEE P1619
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20 | * <https://ieeexplore.ieee.org/servlet/opac?punumber=4375278>.
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21 | */
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22 |
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23 | /* Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved.
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24 | * SPDX-License-Identifier: Apache-2.0
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25 | *
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26 | * Licensed under the Apache License, Version 2.0 (the "License"); you may
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27 | * not use this file except in compliance with the License.
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28 | * You may obtain a copy of the License at
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29 | *
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30 | * http://www.apache.org/licenses/LICENSE-2.0
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31 | *
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32 | * Unless required by applicable law or agreed to in writing, software
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33 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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34 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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35 | * See the License for the specific language governing permissions and
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36 | * limitations under the License.
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37 | *
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38 | * This file is part of Mbed TLS (https://tls.mbed.org)
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39 | */
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40 |
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41 | #ifndef MBEDTLS_AES_H
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42 | #define MBEDTLS_AES_H
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43 |
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44 | #if !defined(MBEDTLS_CONFIG_FILE)
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45 | #include "config.h"
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46 | #else
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47 | #include MBEDTLS_CONFIG_FILE
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48 | #endif
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49 |
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50 | #include <stddef.h>
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51 | #include <stdint.h>
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52 |
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53 | /* padlock.c and aesni.c rely on these values! */
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54 | #define MBEDTLS_AES_ENCRYPT 1 /**< AES encryption. */
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55 | #define MBEDTLS_AES_DECRYPT 0 /**< AES decryption. */
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56 |
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57 | /* Error codes in range 0x0020-0x0022 */
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58 | #define MBEDTLS_ERR_AES_INVALID_KEY_LENGTH -0x0020 /**< Invalid key length. */
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59 | #define MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH -0x0022 /**< Invalid data input length. */
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60 |
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61 | /* Error codes in range 0x0021-0x0025 */
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62 | #define MBEDTLS_ERR_AES_BAD_INPUT_DATA -0x0021 /**< Invalid input data. */
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63 |
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64 | /* MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE is deprecated and should not be used. */
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65 | #define MBEDTLS_ERR_AES_FEATURE_UNAVAILABLE -0x0023 /**< Feature not available. For example, an unsupported AES key size. */
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66 |
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67 | /* MBEDTLS_ERR_AES_HW_ACCEL_FAILED is deprecated and should not be used. */
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68 | #define MBEDTLS_ERR_AES_HW_ACCEL_FAILED -0x0025 /**< AES hardware accelerator failed. */
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69 |
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70 | #if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
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71 | !defined(inline) && !defined(__cplusplus)
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72 | #define inline __inline
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73 | #endif
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74 |
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75 | #ifdef __cplusplus
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76 | extern "C" {
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77 | #endif
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78 |
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79 | #if !defined(MBEDTLS_AES_ALT)
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80 | // Regular implementation
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81 | //
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82 |
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83 | /**
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84 | * \brief The AES context-type definition.
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85 | */
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86 | typedef struct mbedtls_aes_context
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87 | {
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88 | int nr; /*!< The number of rounds. */
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89 | uint32_t *rk; /*!< AES round keys. */
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90 | uint32_t buf[68]; /*!< Unaligned data buffer. This buffer can
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91 | hold 32 extra Bytes, which can be used for
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92 | one of the following purposes:
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93 | <ul><li>Alignment if VIA padlock is
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94 | used.</li>
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95 | <li>Simplifying key expansion in the 256-bit
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96 | case by generating an extra round key.
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97 | </li></ul> */
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98 | }
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99 | mbedtls_aes_context;
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100 |
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101 | #if defined(MBEDTLS_CIPHER_MODE_XTS)
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102 | /**
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103 | * \brief The AES XTS context-type definition.
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104 | */
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105 | typedef struct mbedtls_aes_xts_context
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106 | {
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107 | mbedtls_aes_context crypt; /*!< The AES context to use for AES block
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108 | encryption or decryption. */
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109 | mbedtls_aes_context tweak; /*!< The AES context used for tweak
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110 | computation. */
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111 | } mbedtls_aes_xts_context;
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112 | #endif /* MBEDTLS_CIPHER_MODE_XTS */
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113 |
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114 | #else /* MBEDTLS_AES_ALT */
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115 | #include "aes_alt.h"
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116 | #endif /* MBEDTLS_AES_ALT */
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117 |
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118 | /**
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119 | * \brief This function initializes the specified AES context.
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120 | *
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121 | * It must be the first API called before using
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122 | * the context.
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123 | *
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124 | * \param ctx The AES context to initialize. This must not be \c NULL.
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125 | */
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126 | void mbedtls_aes_init( mbedtls_aes_context *ctx );
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127 |
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128 | /**
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129 | * \brief This function releases and clears the specified AES context.
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130 | *
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131 | * \param ctx The AES context to clear.
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132 | * If this is \c NULL, this function does nothing.
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133 | * Otherwise, the context must have been at least initialized.
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134 | */
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135 | void mbedtls_aes_free( mbedtls_aes_context *ctx );
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136 |
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137 | #if defined(MBEDTLS_CIPHER_MODE_XTS)
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138 | /**
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139 | * \brief This function initializes the specified AES XTS context.
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140 | *
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141 | * It must be the first API called before using
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142 | * the context.
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143 | *
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144 | * \param ctx The AES XTS context to initialize. This must not be \c NULL.
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145 | */
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146 | void mbedtls_aes_xts_init( mbedtls_aes_xts_context *ctx );
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147 |
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148 | /**
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149 | * \brief This function releases and clears the specified AES XTS context.
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150 | *
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151 | * \param ctx The AES XTS context to clear.
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152 | * If this is \c NULL, this function does nothing.
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153 | * Otherwise, the context must have been at least initialized.
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154 | */
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155 | void mbedtls_aes_xts_free( mbedtls_aes_xts_context *ctx );
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156 | #endif /* MBEDTLS_CIPHER_MODE_XTS */
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157 |
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158 | /**
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159 | * \brief This function sets the encryption key.
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160 | *
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161 | * \param ctx The AES context to which the key should be bound.
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162 | * It must be initialized.
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163 | * \param key The encryption key.
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164 | * This must be a readable buffer of size \p keybits bits.
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165 | * \param keybits The size of data passed in bits. Valid options are:
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166 | * <ul><li>128 bits</li>
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167 | * <li>192 bits</li>
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168 | * <li>256 bits</li></ul>
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169 | *
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170 | * \return \c 0 on success.
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171 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
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172 | */
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173 | int mbedtls_aes_setkey_enc( mbedtls_aes_context *ctx, const unsigned char *key,
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174 | unsigned int keybits );
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175 |
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176 | /**
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177 | * \brief This function sets the decryption key.
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178 | *
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179 | * \param ctx The AES context to which the key should be bound.
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180 | * It must be initialized.
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181 | * \param key The decryption key.
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182 | * This must be a readable buffer of size \p keybits bits.
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183 | * \param keybits The size of data passed. Valid options are:
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184 | * <ul><li>128 bits</li>
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185 | * <li>192 bits</li>
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186 | * <li>256 bits</li></ul>
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187 | *
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188 | * \return \c 0 on success.
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189 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
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190 | */
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191 | int mbedtls_aes_setkey_dec( mbedtls_aes_context *ctx, const unsigned char *key,
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192 | unsigned int keybits );
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193 |
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194 | #if defined(MBEDTLS_CIPHER_MODE_XTS)
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195 | /**
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196 | * \brief This function prepares an XTS context for encryption and
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197 | * sets the encryption key.
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198 | *
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199 | * \param ctx The AES XTS context to which the key should be bound.
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200 | * It must be initialized.
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201 | * \param key The encryption key. This is comprised of the XTS key1
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202 | * concatenated with the XTS key2.
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203 | * This must be a readable buffer of size \p keybits bits.
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204 | * \param keybits The size of \p key passed in bits. Valid options are:
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205 | * <ul><li>256 bits (each of key1 and key2 is a 128-bit key)</li>
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206 | * <li>512 bits (each of key1 and key2 is a 256-bit key)</li></ul>
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207 | *
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208 | * \return \c 0 on success.
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209 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
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210 | */
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211 | int mbedtls_aes_xts_setkey_enc( mbedtls_aes_xts_context *ctx,
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212 | const unsigned char *key,
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213 | unsigned int keybits );
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214 |
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215 | /**
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216 | * \brief This function prepares an XTS context for decryption and
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217 | * sets the decryption key.
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218 | *
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219 | * \param ctx The AES XTS context to which the key should be bound.
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220 | * It must be initialized.
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221 | * \param key The decryption key. This is comprised of the XTS key1
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222 | * concatenated with the XTS key2.
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223 | * This must be a readable buffer of size \p keybits bits.
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224 | * \param keybits The size of \p key passed in bits. Valid options are:
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225 | * <ul><li>256 bits (each of key1 and key2 is a 128-bit key)</li>
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226 | * <li>512 bits (each of key1 and key2 is a 256-bit key)</li></ul>
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227 | *
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228 | * \return \c 0 on success.
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229 | * \return #MBEDTLS_ERR_AES_INVALID_KEY_LENGTH on failure.
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230 | */
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231 | int mbedtls_aes_xts_setkey_dec( mbedtls_aes_xts_context *ctx,
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232 | const unsigned char *key,
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233 | unsigned int keybits );
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234 | #endif /* MBEDTLS_CIPHER_MODE_XTS */
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235 |
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236 | /**
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237 | * \brief This function performs an AES single-block encryption or
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238 | * decryption operation.
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239 | *
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240 | * It performs the operation defined in the \p mode parameter
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241 | * (encrypt or decrypt), on the input data buffer defined in
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242 | * the \p input parameter.
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243 | *
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244 | * mbedtls_aes_init(), and either mbedtls_aes_setkey_enc() or
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245 | * mbedtls_aes_setkey_dec() must be called before the first
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246 | * call to this API with the same context.
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247 | *
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248 | * \param ctx The AES context to use for encryption or decryption.
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249 | * It must be initialized and bound to a key.
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250 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or
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251 | * #MBEDTLS_AES_DECRYPT.
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252 | * \param input The buffer holding the input data.
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253 | * It must be readable and at least \c 16 Bytes long.
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254 | * \param output The buffer where the output data will be written.
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255 | * It must be writeable and at least \c 16 Bytes long.
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256 |
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257 | * \return \c 0 on success.
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258 | */
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259 | int mbedtls_aes_crypt_ecb( mbedtls_aes_context *ctx,
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260 | int mode,
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261 | const unsigned char input[16],
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262 | unsigned char output[16] );
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263 |
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264 | #if defined(MBEDTLS_CIPHER_MODE_CBC)
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265 | /**
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266 | * \brief This function performs an AES-CBC encryption or decryption operation
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267 | * on full blocks.
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268 | *
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269 | * It performs the operation defined in the \p mode
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270 | * parameter (encrypt/decrypt), on the input data buffer defined in
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271 | * the \p input parameter.
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272 | *
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273 | * It can be called as many times as needed, until all the input
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274 | * data is processed. mbedtls_aes_init(), and either
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275 | * mbedtls_aes_setkey_enc() or mbedtls_aes_setkey_dec() must be called
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276 | * before the first call to this API with the same context.
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277 | *
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278 | * \note This function operates on full blocks, that is, the input size
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279 | * must be a multiple of the AES block size of \c 16 Bytes.
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280 | *
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281 | * \note Upon exit, the content of the IV is updated so that you can
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282 | * call the same function again on the next
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283 | * block(s) of data and get the same result as if it was
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284 | * encrypted in one call. This allows a "streaming" usage.
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285 | * If you need to retain the contents of the IV, you should
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286 | * either save it manually or use the cipher module instead.
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287 | *
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288 | *
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289 | * \param ctx The AES context to use for encryption or decryption.
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290 | * It must be initialized and bound to a key.
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291 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or
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292 | * #MBEDTLS_AES_DECRYPT.
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293 | * \param length The length of the input data in Bytes. This must be a
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294 | * multiple of the block size (\c 16 Bytes).
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295 | * \param iv Initialization vector (updated after use).
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296 | * It must be a readable and writeable buffer of \c 16 Bytes.
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297 | * \param input The buffer holding the input data.
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298 | * It must be readable and of size \p length Bytes.
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299 | * \param output The buffer holding the output data.
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300 | * It must be writeable and of size \p length Bytes.
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301 | *
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302 | * \return \c 0 on success.
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303 | * \return #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH
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304 | * on failure.
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305 | */
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306 | int mbedtls_aes_crypt_cbc( mbedtls_aes_context *ctx,
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307 | int mode,
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308 | size_t length,
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309 | unsigned char iv[16],
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310 | const unsigned char *input,
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311 | unsigned char *output );
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312 | #endif /* MBEDTLS_CIPHER_MODE_CBC */
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313 |
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314 | #if defined(MBEDTLS_CIPHER_MODE_XTS)
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315 | /**
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316 | * \brief This function performs an AES-XTS encryption or decryption
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317 | * operation for an entire XTS data unit.
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318 | *
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319 | * AES-XTS encrypts or decrypts blocks based on their location as
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320 | * defined by a data unit number. The data unit number must be
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321 | * provided by \p data_unit.
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322 | *
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323 | * NIST SP 800-38E limits the maximum size of a data unit to 2^20
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324 | * AES blocks. If the data unit is larger than this, this function
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325 | * returns #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH.
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326 | *
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327 | * \param ctx The AES XTS context to use for AES XTS operations.
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328 | * It must be initialized and bound to a key.
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329 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or
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330 | * #MBEDTLS_AES_DECRYPT.
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331 | * \param length The length of a data unit in Bytes. This can be any
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332 | * length between 16 bytes and 2^24 bytes inclusive
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333 | * (between 1 and 2^20 block cipher blocks).
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334 | * \param data_unit The address of the data unit encoded as an array of 16
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335 | * bytes in little-endian format. For disk encryption, this
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336 | * is typically the index of the block device sector that
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337 | * contains the data.
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338 | * \param input The buffer holding the input data (which is an entire
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339 | * data unit). This function reads \p length Bytes from \p
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340 | * input.
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341 | * \param output The buffer holding the output data (which is an entire
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342 | * data unit). This function writes \p length Bytes to \p
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343 | * output.
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344 | *
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345 | * \return \c 0 on success.
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346 | * \return #MBEDTLS_ERR_AES_INVALID_INPUT_LENGTH if \p length is
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347 | * smaller than an AES block in size (16 Bytes) or if \p
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348 | * length is larger than 2^20 blocks (16 MiB).
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349 | */
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350 | int mbedtls_aes_crypt_xts( mbedtls_aes_xts_context *ctx,
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351 | int mode,
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352 | size_t length,
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353 | const unsigned char data_unit[16],
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354 | const unsigned char *input,
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355 | unsigned char *output );
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356 | #endif /* MBEDTLS_CIPHER_MODE_XTS */
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357 |
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358 | #if defined(MBEDTLS_CIPHER_MODE_CFB)
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359 | /**
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360 | * \brief This function performs an AES-CFB128 encryption or decryption
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361 | * operation.
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362 | *
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363 | * It performs the operation defined in the \p mode
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364 | * parameter (encrypt or decrypt), on the input data buffer
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365 | * defined in the \p input parameter.
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366 | *
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367 | * For CFB, you must set up the context with mbedtls_aes_setkey_enc(),
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368 | * regardless of whether you are performing an encryption or decryption
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369 | * operation, that is, regardless of the \p mode parameter. This is
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370 | * because CFB mode uses the same key schedule for encryption and
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371 | * decryption.
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372 | *
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373 | * \note Upon exit, the content of the IV is updated so that you can
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374 | * call the same function again on the next
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375 | * block(s) of data and get the same result as if it was
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376 | * encrypted in one call. This allows a "streaming" usage.
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377 | * If you need to retain the contents of the
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378 | * IV, you must either save it manually or use the cipher
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379 | * module instead.
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380 | *
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381 | *
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382 | * \param ctx The AES context to use for encryption or decryption.
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383 | * It must be initialized and bound to a key.
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384 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or
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385 | * #MBEDTLS_AES_DECRYPT.
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386 | * \param length The length of the input data in Bytes.
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387 | * \param iv_off The offset in IV (updated after use).
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388 | * It must point to a valid \c size_t.
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389 | * \param iv The initialization vector (updated after use).
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390 | * It must be a readable and writeable buffer of \c 16 Bytes.
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391 | * \param input The buffer holding the input data.
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392 | * It must be readable and of size \p length Bytes.
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393 | * \param output The buffer holding the output data.
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394 | * It must be writeable and of size \p length Bytes.
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395 | *
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396 | * \return \c 0 on success.
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397 | */
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398 | int mbedtls_aes_crypt_cfb128( mbedtls_aes_context *ctx,
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399 | int mode,
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400 | size_t length,
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401 | size_t *iv_off,
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402 | unsigned char iv[16],
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403 | const unsigned char *input,
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404 | unsigned char *output );
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405 |
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406 | /**
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407 | * \brief This function performs an AES-CFB8 encryption or decryption
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408 | * operation.
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409 | *
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410 | * It performs the operation defined in the \p mode
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411 | * parameter (encrypt/decrypt), on the input data buffer defined
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412 | * in the \p input parameter.
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413 | *
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414 | * Due to the nature of CFB, you must use the same key schedule for
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415 | * both encryption and decryption operations. Therefore, you must
|
---|
416 | * use the context initialized with mbedtls_aes_setkey_enc() for
|
---|
417 | * both #MBEDTLS_AES_ENCRYPT and #MBEDTLS_AES_DECRYPT.
|
---|
418 | *
|
---|
419 | * \note Upon exit, the content of the IV is updated so that you can
|
---|
420 | * call the same function again on the next
|
---|
421 | * block(s) of data and get the same result as if it was
|
---|
422 | * encrypted in one call. This allows a "streaming" usage.
|
---|
423 | * If you need to retain the contents of the
|
---|
424 | * IV, you should either save it manually or use the cipher
|
---|
425 | * module instead.
|
---|
426 | *
|
---|
427 | *
|
---|
428 | * \param ctx The AES context to use for encryption or decryption.
|
---|
429 | * It must be initialized and bound to a key.
|
---|
430 | * \param mode The AES operation: #MBEDTLS_AES_ENCRYPT or
|
---|
431 | * #MBEDTLS_AES_DECRYPT
|
---|
432 | * \param length The length of the input data.
|
---|
433 | * \param iv The initialization vector (updated after use).
|
---|
434 | * It must be a readable and writeable buffer of \c 16 Bytes.
|
---|
435 | * \param input The buffer holding the input data.
|
---|
436 | * It must be readable and of size \p length Bytes.
|
---|
437 | * \param output The buffer holding the output data.
|
---|
438 | * It must be writeable and of size \p length Bytes.
|
---|
439 | *
|
---|
440 | * \return \c 0 on success.
|
---|
441 | */
|
---|
442 | int mbedtls_aes_crypt_cfb8( mbedtls_aes_context *ctx,
|
---|
443 | int mode,
|
---|
444 | size_t length,
|
---|
445 | unsigned char iv[16],
|
---|
446 | const unsigned char *input,
|
---|
447 | unsigned char *output );
|
---|
448 | #endif /*MBEDTLS_CIPHER_MODE_CFB */
|
---|
449 |
|
---|
450 | #if defined(MBEDTLS_CIPHER_MODE_OFB)
|
---|
451 | /**
|
---|
452 | * \brief This function performs an AES-OFB (Output Feedback Mode)
|
---|
453 | * encryption or decryption operation.
|
---|
454 | *
|
---|
455 | * For OFB, you must set up the context with
|
---|
456 | * mbedtls_aes_setkey_enc(), regardless of whether you are
|
---|
457 | * performing an encryption or decryption operation. This is
|
---|
458 | * because OFB mode uses the same key schedule for encryption and
|
---|
459 | * decryption.
|
---|
460 | *
|
---|
461 | * The OFB operation is identical for encryption or decryption,
|
---|
462 | * therefore no operation mode needs to be specified.
|
---|
463 | *
|
---|
464 | * \note Upon exit, the content of iv, the Initialisation Vector, is
|
---|
465 | * updated so that you can call the same function again on the next
|
---|
466 | * block(s) of data and get the same result as if it was encrypted
|
---|
467 | * in one call. This allows a "streaming" usage, by initialising
|
---|
468 | * iv_off to 0 before the first call, and preserving its value
|
---|
469 | * between calls.
|
---|
470 | *
|
---|
471 | * For non-streaming use, the iv should be initialised on each call
|
---|
472 | * to a unique value, and iv_off set to 0 on each call.
|
---|
473 | *
|
---|
474 | * If you need to retain the contents of the initialisation vector,
|
---|
475 | * you must either save it manually or use the cipher module
|
---|
476 | * instead.
|
---|
477 | *
|
---|
478 | * \warning For the OFB mode, the initialisation vector must be unique
|
---|
479 | * every encryption operation. Reuse of an initialisation vector
|
---|
480 | * will compromise security.
|
---|
481 | *
|
---|
482 | * \param ctx The AES context to use for encryption or decryption.
|
---|
483 | * It must be initialized and bound to a key.
|
---|
484 | * \param length The length of the input data.
|
---|
485 | * \param iv_off The offset in IV (updated after use).
|
---|
486 | * It must point to a valid \c size_t.
|
---|
487 | * \param iv The initialization vector (updated after use).
|
---|
488 | * It must be a readable and writeable buffer of \c 16 Bytes.
|
---|
489 | * \param input The buffer holding the input data.
|
---|
490 | * It must be readable and of size \p length Bytes.
|
---|
491 | * \param output The buffer holding the output data.
|
---|
492 | * It must be writeable and of size \p length Bytes.
|
---|
493 | *
|
---|
494 | * \return \c 0 on success.
|
---|
495 | */
|
---|
496 | int mbedtls_aes_crypt_ofb( mbedtls_aes_context *ctx,
|
---|
497 | size_t length,
|
---|
498 | size_t *iv_off,
|
---|
499 | unsigned char iv[16],
|
---|
500 | const unsigned char *input,
|
---|
501 | unsigned char *output );
|
---|
502 |
|
---|
503 | #endif /* MBEDTLS_CIPHER_MODE_OFB */
|
---|
504 |
|
---|
505 | #if defined(MBEDTLS_CIPHER_MODE_CTR)
|
---|
506 | /**
|
---|
507 | * \brief This function performs an AES-CTR encryption or decryption
|
---|
508 | * operation.
|
---|
509 | *
|
---|
510 | * This function performs the operation defined in the \p mode
|
---|
511 | * parameter (encrypt/decrypt), on the input data buffer
|
---|
512 | * defined in the \p input parameter.
|
---|
513 | *
|
---|
514 | * Due to the nature of CTR, you must use the same key schedule
|
---|
515 | * for both encryption and decryption operations. Therefore, you
|
---|
516 | * must use the context initialized with mbedtls_aes_setkey_enc()
|
---|
517 | * for both #MBEDTLS_AES_ENCRYPT and #MBEDTLS_AES_DECRYPT.
|
---|
518 | *
|
---|
519 | * \warning You must never reuse a nonce value with the same key. Doing so
|
---|
520 | * would void the encryption for the two messages encrypted with
|
---|
521 | * the same nonce and key.
|
---|
522 | *
|
---|
523 | * There are two common strategies for managing nonces with CTR:
|
---|
524 | *
|
---|
525 | * 1. You can handle everything as a single message processed over
|
---|
526 | * successive calls to this function. In that case, you want to
|
---|
527 | * set \p nonce_counter and \p nc_off to 0 for the first call, and
|
---|
528 | * then preserve the values of \p nonce_counter, \p nc_off and \p
|
---|
529 | * stream_block across calls to this function as they will be
|
---|
530 | * updated by this function.
|
---|
531 | *
|
---|
532 | * With this strategy, you must not encrypt more than 2**128
|
---|
533 | * blocks of data with the same key.
|
---|
534 | *
|
---|
535 | * 2. You can encrypt separate messages by dividing the \p
|
---|
536 | * nonce_counter buffer in two areas: the first one used for a
|
---|
537 | * per-message nonce, handled by yourself, and the second one
|
---|
538 | * updated by this function internally.
|
---|
539 | *
|
---|
540 | * For example, you might reserve the first 12 bytes for the
|
---|
541 | * per-message nonce, and the last 4 bytes for internal use. In that
|
---|
542 | * case, before calling this function on a new message you need to
|
---|
543 | * set the first 12 bytes of \p nonce_counter to your chosen nonce
|
---|
544 | * value, the last 4 to 0, and \p nc_off to 0 (which will cause \p
|
---|
545 | * stream_block to be ignored). That way, you can encrypt at most
|
---|
546 | * 2**96 messages of up to 2**32 blocks each with the same key.
|
---|
547 | *
|
---|
548 | * The per-message nonce (or information sufficient to reconstruct
|
---|
549 | * it) needs to be communicated with the ciphertext and must be unique.
|
---|
550 | * The recommended way to ensure uniqueness is to use a message
|
---|
551 | * counter. An alternative is to generate random nonces, but this
|
---|
552 | * limits the number of messages that can be securely encrypted:
|
---|
553 | * for example, with 96-bit random nonces, you should not encrypt
|
---|
554 | * more than 2**32 messages with the same key.
|
---|
555 | *
|
---|
556 | * Note that for both stategies, sizes are measured in blocks and
|
---|
557 | * that an AES block is 16 bytes.
|
---|
558 | *
|
---|
559 | * \warning Upon return, \p stream_block contains sensitive data. Its
|
---|
560 | * content must not be written to insecure storage and should be
|
---|
561 | * securely discarded as soon as it's no longer needed.
|
---|
562 | *
|
---|
563 | * \param ctx The AES context to use for encryption or decryption.
|
---|
564 | * It must be initialized and bound to a key.
|
---|
565 | * \param length The length of the input data.
|
---|
566 | * \param nc_off The offset in the current \p stream_block, for
|
---|
567 | * resuming within the current cipher stream. The
|
---|
568 | * offset pointer should be 0 at the start of a stream.
|
---|
569 | * It must point to a valid \c size_t.
|
---|
570 | * \param nonce_counter The 128-bit nonce and counter.
|
---|
571 | * It must be a readable-writeable buffer of \c 16 Bytes.
|
---|
572 | * \param stream_block The saved stream block for resuming. This is
|
---|
573 | * overwritten by the function.
|
---|
574 | * It must be a readable-writeable buffer of \c 16 Bytes.
|
---|
575 | * \param input The buffer holding the input data.
|
---|
576 | * It must be readable and of size \p length Bytes.
|
---|
577 | * \param output The buffer holding the output data.
|
---|
578 | * It must be writeable and of size \p length Bytes.
|
---|
579 | *
|
---|
580 | * \return \c 0 on success.
|
---|
581 | */
|
---|
582 | int mbedtls_aes_crypt_ctr( mbedtls_aes_context *ctx,
|
---|
583 | size_t length,
|
---|
584 | size_t *nc_off,
|
---|
585 | unsigned char nonce_counter[16],
|
---|
586 | unsigned char stream_block[16],
|
---|
587 | const unsigned char *input,
|
---|
588 | unsigned char *output );
|
---|
589 | #endif /* MBEDTLS_CIPHER_MODE_CTR */
|
---|
590 |
|
---|
591 | /**
|
---|
592 | * \brief Internal AES block encryption function. This is only
|
---|
593 | * exposed to allow overriding it using
|
---|
594 | * \c MBEDTLS_AES_ENCRYPT_ALT.
|
---|
595 | *
|
---|
596 | * \param ctx The AES context to use for encryption.
|
---|
597 | * \param input The plaintext block.
|
---|
598 | * \param output The output (ciphertext) block.
|
---|
599 | *
|
---|
600 | * \return \c 0 on success.
|
---|
601 | */
|
---|
602 | int mbedtls_internal_aes_encrypt( mbedtls_aes_context *ctx,
|
---|
603 | const unsigned char input[16],
|
---|
604 | unsigned char output[16] );
|
---|
605 |
|
---|
606 | /**
|
---|
607 | * \brief Internal AES block decryption function. This is only
|
---|
608 | * exposed to allow overriding it using see
|
---|
609 | * \c MBEDTLS_AES_DECRYPT_ALT.
|
---|
610 | *
|
---|
611 | * \param ctx The AES context to use for decryption.
|
---|
612 | * \param input The ciphertext block.
|
---|
613 | * \param output The output (plaintext) block.
|
---|
614 | *
|
---|
615 | * \return \c 0 on success.
|
---|
616 | */
|
---|
617 | int mbedtls_internal_aes_decrypt( mbedtls_aes_context *ctx,
|
---|
618 | const unsigned char input[16],
|
---|
619 | unsigned char output[16] );
|
---|
620 |
|
---|
621 | #if !defined(MBEDTLS_DEPRECATED_REMOVED)
|
---|
622 | #if defined(MBEDTLS_DEPRECATED_WARNING)
|
---|
623 | #define MBEDTLS_DEPRECATED __attribute__((deprecated))
|
---|
624 | #else
|
---|
625 | #define MBEDTLS_DEPRECATED
|
---|
626 | #endif
|
---|
627 | /**
|
---|
628 | * \brief Deprecated internal AES block encryption function
|
---|
629 | * without return value.
|
---|
630 | *
|
---|
631 | * \deprecated Superseded by mbedtls_internal_aes_encrypt()
|
---|
632 | *
|
---|
633 | * \param ctx The AES context to use for encryption.
|
---|
634 | * \param input Plaintext block.
|
---|
635 | * \param output Output (ciphertext) block.
|
---|
636 | */
|
---|
637 | MBEDTLS_DEPRECATED void mbedtls_aes_encrypt( mbedtls_aes_context *ctx,
|
---|
638 | const unsigned char input[16],
|
---|
639 | unsigned char output[16] );
|
---|
640 |
|
---|
641 | /**
|
---|
642 | * \brief Deprecated internal AES block decryption function
|
---|
643 | * without return value.
|
---|
644 | *
|
---|
645 | * \deprecated Superseded by mbedtls_internal_aes_decrypt()
|
---|
646 | *
|
---|
647 | * \param ctx The AES context to use for decryption.
|
---|
648 | * \param input Ciphertext block.
|
---|
649 | * \param output Output (plaintext) block.
|
---|
650 | */
|
---|
651 | MBEDTLS_DEPRECATED void mbedtls_aes_decrypt( mbedtls_aes_context *ctx,
|
---|
652 | const unsigned char input[16],
|
---|
653 | unsigned char output[16] );
|
---|
654 |
|
---|
655 | #undef MBEDTLS_DEPRECATED
|
---|
656 | #endif /* !MBEDTLS_DEPRECATED_REMOVED */
|
---|
657 |
|
---|
658 |
|
---|
659 | #if defined(MBEDTLS_SELF_TEST)
|
---|
660 | /**
|
---|
661 | * \brief Checkup routine.
|
---|
662 | *
|
---|
663 | * \return \c 0 on success.
|
---|
664 | * \return \c 1 on failure.
|
---|
665 | */
|
---|
666 | int mbedtls_aes_self_test( int verbose );
|
---|
667 |
|
---|
668 | #endif /* MBEDTLS_SELF_TEST */
|
---|
669 |
|
---|
670 | #ifdef __cplusplus
|
---|
671 | }
|
---|
672 | #endif
|
---|
673 |
|
---|
674 | #endif /* aes.h */
|
---|