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[proxmark3-svn] / common / hmac_drbg.h
1 /**
2 * \file hmac_drbg.h
3 *
4 * \brief HMAC_DRBG (NIST SP 800-90A)
5 *
6 * Copyright (C) 2014, ARM Limited, All Rights Reserved
7 *
8 * This file is part of mbed TLS (https://tls.mbed.org)
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License along
21 * with this program; if not, write to the Free Software Foundation, Inc.,
22 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
23 */
24 #ifndef MBEDTLS_HMAC_DRBG_H
25 #define MBEDTLS_HMAC_DRBG_H
26
27 #include "md.h"
28
29 #if defined(MBEDTLS_THREADING_C)
30 #include "mbedtls/threading.h"
31 #endif
32
33 /*
34 * Error codes
35 */
36 #define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG -0x0003 /**< Too many random requested in single call. */
37 #define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG -0x0005 /**< Input too large (Entropy + additional). */
38 #define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR -0x0007 /**< Read/write error in file. */
39 #define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED -0x0009 /**< The entropy source failed. */
40
41 /**
42 * \name SECTION: Module settings
43 *
44 * The configuration options you can set for this module are in this section.
45 * Either change them in config.h or define them on the compiler command line.
46 * \{
47 */
48
49 #if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
50 #define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL 10000 /**< Interval before reseed is performed by default */
51 #endif
52
53 #if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT)
54 #define MBEDTLS_HMAC_DRBG_MAX_INPUT 256 /**< Maximum number of additional input bytes */
55 #endif
56
57 #if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST)
58 #define MBEDTLS_HMAC_DRBG_MAX_REQUEST 1024 /**< Maximum number of requested bytes per call */
59 #endif
60
61 #if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT)
62 #define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT 384 /**< Maximum size of (re)seed buffer */
63 #endif
64
65 /* \} name SECTION: Module settings */
66
67 #define MBEDTLS_HMAC_DRBG_PR_OFF 0 /**< No prediction resistance */
68 #define MBEDTLS_HMAC_DRBG_PR_ON 1 /**< Prediction resistance enabled */
69
70 #ifdef __cplusplus
71 extern "C" {
72 #endif
73
74 /**
75 * HMAC_DRBG context.
76 */
77 typedef struct
78 {
79 /* Working state: the key K is not stored explicitely,
80 * but is implied by the HMAC context */
81 mbedtls_md_context_t md_ctx; /*!< HMAC context (inc. K) */
82 unsigned char V[MBEDTLS_MD_MAX_SIZE]; /*!< V in the spec */
83 int reseed_counter; /*!< reseed counter */
84
85 /* Administrative state */
86 size_t entropy_len; /*!< entropy bytes grabbed on each (re)seed */
87 int prediction_resistance; /*!< enable prediction resistance (Automatic
88 reseed before every random generation) */
89 int reseed_interval; /*!< reseed interval */
90
91 /* Callbacks */
92 int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */
93 void *p_entropy; /*!< context for the entropy function */
94
95 #if defined(MBEDTLS_THREADING_C)
96 mbedtls_threading_mutex_t mutex;
97 #endif
98 } mbedtls_hmac_drbg_context;
99
100 /**
101 * \brief HMAC_DRBG context initialization
102 * Makes the context ready for mbetls_hmac_drbg_seed(),
103 * mbedtls_hmac_drbg_seed_buf() or
104 * mbedtls_hmac_drbg_free().
105 *
106 * \param ctx HMAC_DRBG context to be initialized
107 */
108 void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx );
109
110 /**
111 * \brief HMAC_DRBG initial seeding
112 * Seed and setup entropy source for future reseeds.
113 *
114 * \param ctx HMAC_DRBG context to be seeded
115 * \param md_info MD algorithm to use for HMAC_DRBG
116 * \param f_entropy Entropy callback (p_entropy, buffer to fill, buffer
117 * length)
118 * \param p_entropy Entropy context
119 * \param custom Personalization data (Device specific identifiers)
120 * (Can be NULL)
121 * \param len Length of personalization data
122 *
123 * \note The "security strength" as defined by NIST is set to:
124 * 128 bits if md_alg is SHA-1,
125 * 192 bits if md_alg is SHA-224,
126 * 256 bits if md_alg is SHA-256 or higher.
127 * Note that SHA-256 is just as efficient as SHA-224.
128 *
129 * \return 0 if successful, or
130 * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or
131 * MBEDTLS_ERR_MD_ALLOC_FAILED, or
132 * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED.
133 */
134 int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx,
135 const mbedtls_md_info_t * md_info,
136 int (*f_entropy)(void *, unsigned char *, size_t),
137 void *p_entropy,
138 const unsigned char *custom,
139 size_t len );
140
141 /**
142 * \brief Initilisation of simpified HMAC_DRBG (never reseeds).
143 * (For use with deterministic ECDSA.)
144 *
145 * \param ctx HMAC_DRBG context to be initialised
146 * \param md_info MD algorithm to use for HMAC_DRBG
147 * \param data Concatenation of entropy string and additional data
148 * \param data_len Length of data in bytes
149 *
150 * \return 0 if successful, or
151 * MBEDTLS_ERR_MD_BAD_INPUT_DATA, or
152 * MBEDTLS_ERR_MD_ALLOC_FAILED.
153 */
154 int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx,
155 const mbedtls_md_info_t * md_info,
156 const unsigned char *data, size_t data_len );
157
158 /**
159 * \brief Enable / disable prediction resistance (Default: Off)
160 *
161 * Note: If enabled, entropy is used for ctx->entropy_len before each call!
162 * Only use this if you have ample supply of good entropy!
163 *
164 * \param ctx HMAC_DRBG context
165 * \param resistance MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF
166 */
167 void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx,
168 int resistance );
169
170 /**
171 * \brief Set the amount of entropy grabbed on each reseed
172 * (Default: given by the security strength, which
173 * depends on the hash used, see \c mbedtls_hmac_drbg_init() )
174 *
175 * \param ctx HMAC_DRBG context
176 * \param len Amount of entropy to grab, in bytes
177 */
178 void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx,
179 size_t len );
180
181 /**
182 * \brief Set the reseed interval
183 * (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
184 *
185 * \param ctx HMAC_DRBG context
186 * \param interval Reseed interval
187 */
188 void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx,
189 int interval );
190
191 /**
192 * \brief HMAC_DRBG update state
193 *
194 * \param ctx HMAC_DRBG context
195 * \param additional Additional data to update state with, or NULL
196 * \param add_len Length of additional data, or 0
197 *
198 * \note Additional data is optional, pass NULL and 0 as second
199 * third argument if no additional data is being used.
200 */
201 void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx,
202 const unsigned char *additional, size_t add_len );
203
204 /**
205 * \brief HMAC_DRBG reseeding (extracts data from entropy source)
206 *
207 * \param ctx HMAC_DRBG context
208 * \param additional Additional data to add to state (Can be NULL)
209 * \param len Length of additional data
210 *
211 * \return 0 if successful, or
212 * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
213 */
214 int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx,
215 const unsigned char *additional, size_t len );
216
217 /**
218 * \brief HMAC_DRBG generate random with additional update input
219 *
220 * Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
221 *
222 * \param p_rng HMAC_DRBG context
223 * \param output Buffer to fill
224 * \param output_len Length of the buffer
225 * \param additional Additional data to update with (can be NULL)
226 * \param add_len Length of additional data (can be 0)
227 *
228 * \return 0 if successful, or
229 * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
230 * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or
231 * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG.
232 */
233 int mbedtls_hmac_drbg_random_with_add( void *p_rng,
234 unsigned char *output, size_t output_len,
235 const unsigned char *additional,
236 size_t add_len );
237
238 /**
239 * \brief HMAC_DRBG generate random
240 *
241 * Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
242 *
243 * \param p_rng HMAC_DRBG context
244 * \param output Buffer to fill
245 * \param out_len Length of the buffer
246 *
247 * \return 0 if successful, or
248 * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
249 * MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG
250 */
251 int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );
252
253 /**
254 * \brief Free an HMAC_DRBG context
255 *
256 * \param ctx HMAC_DRBG context to free.
257 */
258 void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx );
259
260 #if defined(MBEDTLS_FS_IO)
261 /**
262 * \brief Write a seed file
263 *
264 * \param ctx HMAC_DRBG context
265 * \param path Name of the file
266 *
267 * \return 0 if successful, 1 on file error, or
268 * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
269 */
270 int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
271
272 /**
273 * \brief Read and update a seed file. Seed is added to this
274 * instance
275 *
276 * \param ctx HMAC_DRBG context
277 * \param path Name of the file
278 *
279 * \return 0 if successful, 1 on file error,
280 * MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or
281 * MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG
282 */
283 int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
284 #endif /* MBEDTLS_FS_IO */
285
286
287 #if defined(MBEDTLS_SELF_TEST)
288 /**
289 * \brief Checkup routine
290 *
291 * \return 0 if successful, or 1 if the test failed
292 */
293 int mbedtls_hmac_drbg_self_test( int verbose );
294 #endif
295
296 #ifdef __cplusplus
297 }
298 #endif
299
300 #endif /* hmac_drbg.h */
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