1 /** 2 * \file nist_kw.h 3 * 4 * \brief This file provides an API for key wrapping (KW) and key wrapping with 5 * padding (KWP) as defined in NIST SP 800-38F. 6 * https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-38F.pdf 7 * 8 * Key wrapping specifies a deterministic authenticated-encryption mode 9 * of operation, according to <em>NIST SP 800-38F: Recommendation for 10 * Block Cipher Modes of Operation: Methods for Key Wrapping</em>. Its 11 * purpose is to protect cryptographic keys. 12 * 13 * Its equivalent is RFC 3394 for KW, and RFC 5649 for KWP. 14 * https://tools.ietf.org/html/rfc3394 15 * https://tools.ietf.org/html/rfc5649 16 * 17 */ 18 /* 19 * Copyright The Mbed TLS Contributors 20 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later 21 * 22 * This file is provided under the Apache License 2.0, or the 23 * GNU General Public License v2.0 or later. 24 * 25 * ********** 26 * Apache License 2.0: 27 * 28 * Licensed under the Apache License, Version 2.0 (the "License"); you may 29 * not use this file except in compliance with the License. 30 * You may obtain a copy of the License at 31 * 32 * http://www.apache.org/licenses/LICENSE-2.0 33 * 34 * Unless required by applicable law or agreed to in writing, software 35 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 36 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 37 * See the License for the specific language governing permissions and 38 * limitations under the License. 39 * 40 * ********** 41 * 42 * ********** 43 * GNU General Public License v2.0 or later: 44 * 45 * This program is free software; you can redistribute it and/or modify 46 * it under the terms of the GNU General Public License as published by 47 * the Free Software Foundation; either version 2 of the License, or 48 * (at your option) any later version. 49 * 50 * This program is distributed in the hope that it will be useful, 51 * but WITHOUT ANY WARRANTY; without even the implied warranty of 52 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 53 * GNU General Public License for more details. 54 * 55 * You should have received a copy of the GNU General Public License along 56 * with this program; if not, write to the Free Software Foundation, Inc., 57 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. 58 * 59 * ********** 60 */ 61 62 #ifndef MBEDTLS_NIST_KW_H 63 #define MBEDTLS_NIST_KW_H 64 65 #if !defined(MBEDTLS_CONFIG_FILE) 66 #include "config.h" 67 #else 68 #include MBEDTLS_CONFIG_FILE 69 #endif 70 71 #include "cipher.h" 72 73 #ifdef __cplusplus 74 extern "C" { 75 #endif 76 77 typedef enum 78 { 79 MBEDTLS_KW_MODE_KW = 0, 80 MBEDTLS_KW_MODE_KWP = 1 81 } mbedtls_nist_kw_mode_t; 82 83 #if !defined(MBEDTLS_NIST_KW_ALT) 84 // Regular implementation 85 // 86 87 /** 88 * \brief The key wrapping context-type definition. The key wrapping context is passed 89 * to the APIs called. 90 * 91 * \note The definition of this type may change in future library versions. 92 * Don't make any assumptions on this context! 93 */ 94 typedef struct { 95 mbedtls_cipher_context_t cipher_ctx; /*!< The cipher context used. */ 96 } mbedtls_nist_kw_context; 97 98 #else /* MBEDTLS_NIST_key wrapping_ALT */ 99 #include "nist_kw_alt.h" 100 #endif /* MBEDTLS_NIST_KW_ALT */ 101 102 /** 103 * \brief This function initializes the specified key wrapping context 104 * to make references valid and prepare the context 105 * for mbedtls_nist_kw_setkey() or mbedtls_nist_kw_free(). 106 * 107 * \param ctx The key wrapping context to initialize. 108 * 109 */ 110 void mbedtls_nist_kw_init( mbedtls_nist_kw_context *ctx ); 111 112 /** 113 * \brief This function initializes the key wrapping context set in the 114 * \p ctx parameter and sets the encryption key. 115 * 116 * \param ctx The key wrapping context. 117 * \param cipher The 128-bit block cipher to use. Only AES is supported. 118 * \param key The Key Encryption Key (KEK). 119 * \param keybits The KEK size in bits. This must be acceptable by the cipher. 120 * \param is_wrap Specify whether the operation within the context is wrapping or unwrapping 121 * 122 * \return \c 0 on success. 123 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for any invalid input. 124 * \return \c MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE for 128-bit block ciphers 125 * which are not supported. 126 * \return cipher-specific error code on failure of the underlying cipher. 127 */ 128 int mbedtls_nist_kw_setkey( mbedtls_nist_kw_context *ctx, 129 mbedtls_cipher_id_t cipher, 130 const unsigned char *key, 131 unsigned int keybits, 132 const int is_wrap ); 133 134 /** 135 * \brief This function releases and clears the specified key wrapping context 136 * and underlying cipher sub-context. 137 * 138 * \param ctx The key wrapping context to clear. 139 */ 140 void mbedtls_nist_kw_free( mbedtls_nist_kw_context *ctx ); 141 142 /** 143 * \brief This function encrypts a buffer using key wrapping. 144 * 145 * \param ctx The key wrapping context to use for encryption. 146 * \param mode The key wrapping mode to use (MBEDTLS_KW_MODE_KW or MBEDTLS_KW_MODE_KWP) 147 * \param input The buffer holding the input data. 148 * \param in_len The length of the input data in Bytes. 149 * The input uses units of 8 Bytes called semiblocks. 150 * <ul><li>For KW mode: a multiple of 8 bytes between 16 and 2^57-8 inclusive. </li> 151 * <li>For KWP mode: any length between 1 and 2^32-1 inclusive.</li></ul> 152 * \param[out] output The buffer holding the output data. 153 * <ul><li>For KW mode: Must be at least 8 bytes larger than \p in_len.</li> 154 * <li>For KWP mode: Must be at least 8 bytes larger rounded up to a multiple of 155 * 8 bytes for KWP (15 bytes at most).</li></ul> 156 * \param[out] out_len The number of bytes written to the output buffer. \c 0 on failure. 157 * \param[in] out_size The capacity of the output buffer. 158 * 159 * \return \c 0 on success. 160 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for invalid input length. 161 * \return cipher-specific error code on failure of the underlying cipher. 162 */ 163 int mbedtls_nist_kw_wrap( mbedtls_nist_kw_context *ctx, mbedtls_nist_kw_mode_t mode, 164 const unsigned char *input, size_t in_len, 165 unsigned char *output, size_t* out_len, size_t out_size ); 166 167 /** 168 * \brief This function decrypts a buffer using key wrapping. 169 * 170 * \param ctx The key wrapping context to use for decryption. 171 * \param mode The key wrapping mode to use (MBEDTLS_KW_MODE_KW or MBEDTLS_KW_MODE_KWP) 172 * \param input The buffer holding the input data. 173 * \param in_len The length of the input data in Bytes. 174 * The input uses units of 8 Bytes called semiblocks. 175 * The input must be a multiple of semiblocks. 176 * <ul><li>For KW mode: a multiple of 8 bytes between 24 and 2^57 inclusive. </li> 177 * <li>For KWP mode: a multiple of 8 bytes between 16 and 2^32 inclusive.</li></ul> 178 * \param[out] output The buffer holding the output data. 179 * The output buffer's minimal length is 8 bytes shorter than \p in_len. 180 * \param[out] out_len The number of bytes written to the output buffer. \c 0 on failure. 181 * For KWP mode, the length could be up to 15 bytes shorter than \p in_len, 182 * depending on how much padding was added to the data. 183 * \param[in] out_size The capacity of the output buffer. 184 * 185 * \return \c 0 on success. 186 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for invalid input length. 187 * \return \c MBEDTLS_ERR_CIPHER_AUTH_FAILED for verification failure of the ciphertext. 188 * \return cipher-specific error code on failure of the underlying cipher. 189 */ 190 int mbedtls_nist_kw_unwrap( mbedtls_nist_kw_context *ctx, mbedtls_nist_kw_mode_t mode, 191 const unsigned char *input, size_t in_len, 192 unsigned char *output, size_t* out_len, size_t out_size); 193 194 195 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C) 196 /** 197 * \brief The key wrapping checkup routine. 198 * 199 * \return \c 0 on success. 200 * \return \c 1 on failure. 201 */ 202 int mbedtls_nist_kw_self_test( int verbose ); 203 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */ 204 205 #ifdef __cplusplus 206 } 207 #endif 208 209 #endif /* MBEDTLS_NIST_KW_H */ 210