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
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.
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
19 * Copyright (C) 2018, Arm Limited (or its affiliates), All Rights Reserved
20 * SPDX-License-Identifier: Apache-2.0
22 * Licensed under the Apache License, Version 2.0 (the "License"); you may
23 * not use this file except in compliance with the License.
24 * You may obtain a copy of the License at
26 * http://www.apache.org/licenses/LICENSE-2.0
28 * Unless required by applicable law or agreed to in writing, software
29 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
30 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
31 * See the License for the specific language governing permissions and
32 * limitations under the License.
34 * This file is part of Mbed TLS (https://tls.mbed.org)
37 #ifndef MBEDTLS_NIST_KW_H
38 #define MBEDTLS_NIST_KW_H
40 #if !defined(MBEDTLS_CONFIG_FILE)
43 #include MBEDTLS_CONFIG_FILE
54 MBEDTLS_KW_MODE_KW = 0,
55 MBEDTLS_KW_MODE_KWP = 1
56 } mbedtls_nist_kw_mode_t;
58 #if !defined(MBEDTLS_NIST_KW_ALT)
59 // Regular implementation
63 * \brief The key wrapping context-type definition. The key wrapping context is passed
66 * \note The definition of this type may change in future library versions.
67 * Don't make any assumptions on this context!
70 mbedtls_cipher_context_t cipher_ctx; /*!< The cipher context used. */
71 } mbedtls_nist_kw_context;
73 #else /* MBEDTLS_NIST_key wrapping_ALT */
74 #include "nist_kw_alt.h"
75 #endif /* MBEDTLS_NIST_KW_ALT */
78 * \brief This function initializes the specified key wrapping context
79 * to make references valid and prepare the context
80 * for mbedtls_nist_kw_setkey() or mbedtls_nist_kw_free().
82 * \param ctx The key wrapping context to initialize.
85 void mbedtls_nist_kw_init( mbedtls_nist_kw_context *ctx );
88 * \brief This function initializes the key wrapping context set in the
89 * \p ctx parameter and sets the encryption key.
91 * \param ctx The key wrapping context.
92 * \param cipher The 128-bit block cipher to use. Only AES is supported.
93 * \param key The Key Encryption Key (KEK).
94 * \param keybits The KEK size in bits. This must be acceptable by the cipher.
95 * \param is_wrap Specify whether the operation within the context is wrapping or unwrapping
97 * \return \c 0 on success.
98 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for any invalid input.
99 * \return \c MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE for 128-bit block ciphers
100 * which are not supported.
101 * \return cipher-specific error code on failure of the underlying cipher.
103 int mbedtls_nist_kw_setkey( mbedtls_nist_kw_context *ctx,
104 mbedtls_cipher_id_t cipher,
105 const unsigned char *key,
106 unsigned int keybits,
110 * \brief This function releases and clears the specified key wrapping context
111 * and underlying cipher sub-context.
113 * \param ctx The key wrapping context to clear.
115 void mbedtls_nist_kw_free( mbedtls_nist_kw_context *ctx );
118 * \brief This function encrypts a buffer using key wrapping.
120 * \param ctx The key wrapping context to use for encryption.
121 * \param mode The key wrapping mode to use (MBEDTLS_KW_MODE_KW or MBEDTLS_KW_MODE_KWP)
122 * \param input The buffer holding the input data.
123 * \param in_len The length of the input data in Bytes.
124 * The input uses units of 8 Bytes called semiblocks.
125 * <ul><li>For KW mode: a multiple of 8 bytes between 16 and 2^57-8 inclusive. </li>
126 * <li>For KWP mode: any length between 1 and 2^32-1 inclusive.</li></ul>
127 * \param[out] output The buffer holding the output data.
128 * <ul><li>For KW mode: Must be at least 8 bytes larger than \p in_len.</li>
129 * <li>For KWP mode: Must be at least 8 bytes larger rounded up to a multiple of
130 * 8 bytes for KWP (15 bytes at most).</li></ul>
131 * \param[out] out_len The number of bytes written to the output buffer. \c 0 on failure.
132 * \param[in] out_size The capacity of the output buffer.
134 * \return \c 0 on success.
135 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for invalid input length.
136 * \return cipher-specific error code on failure of the underlying cipher.
138 int mbedtls_nist_kw_wrap( mbedtls_nist_kw_context *ctx, mbedtls_nist_kw_mode_t mode,
139 const unsigned char *input, size_t in_len,
140 unsigned char *output, size_t* out_len, size_t out_size );
143 * \brief This function decrypts a buffer using key wrapping.
145 * \param ctx The key wrapping context to use for decryption.
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 * The input must be a multiple of semiblocks.
151 * <ul><li>For KW mode: a multiple of 8 bytes between 24 and 2^57 inclusive. </li>
152 * <li>For KWP mode: a multiple of 8 bytes between 16 and 2^32 inclusive.</li></ul>
153 * \param[out] output The buffer holding the output data.
154 * The output buffer's minimal length is 8 bytes shorter than \p in_len.
155 * \param[out] out_len The number of bytes written to the output buffer. \c 0 on failure.
156 * For KWP mode, the length could be up to 15 bytes shorter than \p in_len,
157 * depending on how much padding was added to the data.
158 * \param[in] out_size The capacity of the output buffer.
160 * \return \c 0 on success.
161 * \return \c MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA for invalid input length.
162 * \return \c MBEDTLS_ERR_CIPHER_AUTH_FAILED for verification failure of the ciphertext.
163 * \return cipher-specific error code on failure of the underlying cipher.
165 int mbedtls_nist_kw_unwrap( mbedtls_nist_kw_context *ctx, mbedtls_nist_kw_mode_t mode,
166 const unsigned char *input, size_t in_len,
167 unsigned char *output, size_t* out_len, size_t out_size);
170 #if defined(MBEDTLS_SELF_TEST) && defined(MBEDTLS_AES_C)
172 * \brief The key wrapping checkup routine.
174 * \return \c 0 on success.
175 * \return \c 1 on failure.
177 int mbedtls_nist_kw_self_test( int verbose );
178 #endif /* MBEDTLS_SELF_TEST && MBEDTLS_AES_C */
184 #endif /* MBEDTLS_NIST_KW_H */