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 23 #ifndef MBEDTLS_NIST_KW_H 24 #define MBEDTLS_NIST_KW_H 25 26 #if !defined(MBEDTLS_CONFIG_FILE) 27 #include "mbedtls/config.h" 28 #else 29 #include MBEDTLS_CONFIG_FILE 30 #endif 31 32 #include "mbedtls/cipher.h" 33 34 #ifdef __cplusplus 35 extern "C" { 36 #endif 37 38 typedef enum { 39 MBEDTLS_KW_MODE_KW = 0, 40 MBEDTLS_KW_MODE_KWP = 1 41 } mbedtls_nist_kw_mode_t; 42 43 #if !defined(MBEDTLS_NIST_KW_ALT) 44 // Regular implementation 45 // 46 47 /** 48 * \brief The key wrapping context-type definition. The key wrapping context is passed 49 * to the APIs called. 50 * 51 * \note The definition of this type may change in future library versions. 52 * Don't make any assumptions on this context! 53 */ 54 typedef struct { 55 mbedtls_cipher_context_t cipher_ctx; /*!< The cipher context used. */ 56 } mbedtls_nist_kw_context; 57 58 #else /* MBEDTLS_NIST_key wrapping_ALT */ 59 #include "nist_kw_alt.h" 60 #endif /* MBEDTLS_NIST_KW_ALT */ 61 62 /** 63 * \brief This function initializes the specified key wrapping context 64 * to make references valid and prepare the context 65 * for mbedtls_nist_kw_setkey() or mbedtls_nist_kw_free(). 66 * 67 * \param ctx The key wrapping context to initialize. 68 * 69 */ 70 void mbedtls_nist_kw_init(mbedtls_nist_kw_context *ctx); 71 72 /** 73 * \brief This function initializes the key wrapping context set in the 74 * \p ctx parameter and sets the encryption key. 75 * 76 * \param ctx The key wrapping context. 77 * \param cipher The 128-bit block cipher to use. Only AES is supported. 78 * \param key The Key Encryption Key (KEK). 79 * \param keybits The KEK size in bits. This must be acceptable by the cipher. 80 * \param is_wrap Specify whether the operation within the context is wrapping or unwrapping 81 * 82 * \return \c 0 on success. 83 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for any invalid input. 84 * \return \c MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE for 128-bit block ciphers 85 * which are not supported. 86 * \return cipher-specific error code on failure of the underlying cipher. 87 */ 88 int mbedtls_nist_kw_setkey(mbedtls_nist_kw_context *ctx, 89 mbedtls_cipher_id_t cipher, 90 const unsigned char *key, 91 unsigned int keybits, 92 const int is_wrap); 93 94 /** 95 * \brief This function releases and clears the specified key wrapping context 96 * and underlying cipher sub-context. 97 * 98 * \param ctx The key wrapping context to clear. 99 */ 100 void mbedtls_nist_kw_free(mbedtls_nist_kw_context *ctx); 101 102 /** 103 * \brief This function encrypts a buffer using key wrapping. 104 * 105 * \param ctx The key wrapping context to use for encryption. 106 * \param mode The key wrapping mode to use (MBEDTLS_KW_MODE_KW or MBEDTLS_KW_MODE_KWP) 107 * \param input The buffer holding the input data. 108 * \param in_len The length of the input data in Bytes. 109 * The input uses units of 8 Bytes called semiblocks. 110 * <ul><li>For KW mode: a multiple of 8 bytes between 16 and 2^57-8 inclusive. </li> 111 * <li>For KWP mode: any length between 1 and 2^32-1 inclusive.</li></ul> 112 * \param[out] output The buffer holding the output data. 113 * <ul><li>For KW mode: Must be at least 8 bytes larger than \p in_len.</li> 114 * <li>For KWP mode: Must be at least 8 bytes larger rounded up to a multiple of 115 * 8 bytes for KWP (15 bytes at most).</li></ul> 116 * \param[out] out_len The number of bytes written to the output buffer. \c 0 on failure. 117 * \param[in] out_size The capacity of the output buffer. 118 * 119 * \return \c 0 on success. 120 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for invalid input length. 121 * \return cipher-specific error code on failure of the underlying cipher. 122 */ 123 int mbedtls_nist_kw_wrap(mbedtls_nist_kw_context *ctx, mbedtls_nist_kw_mode_t mode, 124 const unsigned char *input, size_t in_len, 125 unsigned char *output, size_t *out_len, size_t out_size); 126 127 /** 128 * \brief This function decrypts a buffer using key wrapping. 129 * 130 * \param ctx The key wrapping context to use for decryption. 131 * \param mode The key wrapping mode to use (MBEDTLS_KW_MODE_KW or MBEDTLS_KW_MODE_KWP) 132 * \param input The buffer holding the input data. 133 * \param in_len The length of the input data in Bytes. 134 * The input uses units of 8 Bytes called semiblocks. 135 * The input must be a multiple of semiblocks. 136 * <ul><li>For KW mode: a multiple of 8 bytes between 24 and 2^57 inclusive. </li> 137 * <li>For KWP mode: a multiple of 8 bytes between 16 and 2^32 inclusive.</li></ul> 138 * \param[out] output The buffer holding the output data. 139 * The output buffer's minimal length is 8 bytes shorter than \p in_len. 140 * \param[out] out_len The number of bytes written to the output buffer. \c 0 on failure. 141 * For KWP mode, the length could be up to 15 bytes shorter than \p in_len, 142 * depending on how much padding was added to the data. 143 * \param[in] out_size The capacity of the output buffer. 144 * 145 * \return \c 0 on success. 146 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for invalid input length. 147 * \return \c MBEDTLS_ERR_CIPHER_AUTH_FAILED for verification failure of the ciphertext. 148 * \return cipher-specific error code on failure of the underlying cipher. 149 */ 150 int mbedtls_nist_kw_unwrap(mbedtls_nist_kw_context *ctx, mbedtls_nist_kw_mode_t mode, 151 const unsigned char *input, size_t in_len, 152 unsigned char *output, size_t *out_len, size_t out_size); 153 154 155 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C) 156 /** 157 * \brief The key wrapping checkup routine. 158 * 159 * \return \c 0 on success. 160 * \return \c 1 on failure. 161 */ 162 int mbedtls_nist_kw_self_test(int verbose); 163 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */ 164 165 #ifdef __cplusplus 166 } 167 #endif 168 169 #endif /* MBEDTLS_NIST_KW_H */ 170