ctr_drbg.h 21 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512
  1. /**
  2. * \file ctr_drbg.h
  3. *
  4. * \brief This file contains definitions and functions for the
  5. * CTR_DRBG pseudorandom generator.
  6. *
  7. * CTR_DRBG is a standardized way of building a PRNG from a block-cipher
  8. * in counter mode operation, as defined in <em>NIST SP 800-90A:
  9. * Recommendation for Random Number Generation Using Deterministic Random
  10. * Bit Generators</em>.
  11. *
  12. * The Mbed TLS implementation of CTR_DRBG uses AES-256 (default) or AES-128
  13. * (if \c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled at compile time)
  14. * as the underlying block cipher, with a derivation function.
  15. * The initial seeding grabs #MBEDTLS_CTR_DRBG_ENTROPY_LEN bytes of entropy.
  16. * See the documentation of mbedtls_ctr_drbg_seed() for more details.
  17. *
  18. * Based on NIST SP 800-90A §10.2.1 table 3 and NIST SP 800-57 part 1 table 2,
  19. * here are the security strengths achieved in typical configuration:
  20. * - 256 bits under the default configuration of the library, with AES-256
  21. * and with #MBEDTLS_CTR_DRBG_ENTROPY_LEN set to 48 or more.
  22. * - 256 bits if AES-256 is used, #MBEDTLS_CTR_DRBG_ENTROPY_LEN is set
  23. * to 32 or more, and the DRBG is initialized with an explicit
  24. * nonce in the \c custom parameter to mbedtls_ctr_drbg_seed().
  25. * - 128 bits if AES-256 is used but #MBEDTLS_CTR_DRBG_ENTROPY_LEN is
  26. * between 24 and 47 and the DRBG is not initialized with an explicit
  27. * nonce (see mbedtls_ctr_drbg_seed()).
  28. * - 128 bits if AES-128 is used (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY enabled)
  29. * and #MBEDTLS_CTR_DRBG_ENTROPY_LEN is set to 24 or more (which is
  30. * always the case unless it is explicitly set to a different value
  31. * in config.h).
  32. *
  33. * Note that the value of #MBEDTLS_CTR_DRBG_ENTROPY_LEN defaults to:
  34. * - \c 48 if the module \c MBEDTLS_SHA512_C is enabled and the symbol
  35. * \c MBEDTLS_ENTROPY_FORCE_SHA256 is disabled at compile time.
  36. * This is the default configuration of the library.
  37. * - \c 32 if the module \c MBEDTLS_SHA512_C is disabled at compile time.
  38. * - \c 32 if \c MBEDTLS_ENTROPY_FORCE_SHA256 is enabled at compile time.
  39. */
  40. /*
  41. * Copyright (C) 2006-2019, Arm Limited (or its affiliates), All Rights Reserved
  42. * SPDX-License-Identifier: Apache-2.0
  43. *
  44. * Licensed under the Apache License, Version 2.0 (the "License"); you may
  45. * not use this file except in compliance with the License.
  46. * You may obtain a copy of the License at
  47. *
  48. * http://www.apache.org/licenses/LICENSE-2.0
  49. *
  50. * Unless required by applicable law or agreed to in writing, software
  51. * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  52. * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  53. * See the License for the specific language governing permissions and
  54. * limitations under the License.
  55. *
  56. * This file is part of Mbed TLS (https://tls.mbed.org)
  57. */
  58. #ifndef MBEDTLS_CTR_DRBG_H
  59. #define MBEDTLS_CTR_DRBG_H
  60. #if !defined(MBEDTLS_CONFIG_FILE)
  61. #include "config.h"
  62. #else
  63. #include MBEDTLS_CONFIG_FILE
  64. #endif
  65. #include "aes.h"
  66. #if defined(MBEDTLS_THREADING_C)
  67. #include "threading.h"
  68. #endif
  69. #define MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED -0x0034 /**< The entropy source failed. */
  70. #define MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG -0x0036 /**< The requested random buffer length is too big. */
  71. #define MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG -0x0038 /**< The input (entropy + additional data) is too large. */
  72. #define MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR -0x003A /**< Read or write error in file. */
  73. #define MBEDTLS_CTR_DRBG_BLOCKSIZE 16 /**< The block size used by the cipher. */
  74. #if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
  75. #define MBEDTLS_CTR_DRBG_KEYSIZE 16
  76. /**< The key size in bytes used by the cipher.
  77. *
  78. * Compile-time choice: 16 bytes (128 bits)
  79. * because #MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled.
  80. */
  81. #else
  82. #define MBEDTLS_CTR_DRBG_KEYSIZE 32
  83. /**< The key size in bytes used by the cipher.
  84. *
  85. * Compile-time choice: 32 bytes (256 bits)
  86. * because \c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is disabled.
  87. */
  88. #endif
  89. #define MBEDTLS_CTR_DRBG_KEYBITS ( MBEDTLS_CTR_DRBG_KEYSIZE * 8 ) /**< The key size for the DRBG operation, in bits. */
  90. #define MBEDTLS_CTR_DRBG_SEEDLEN ( MBEDTLS_CTR_DRBG_KEYSIZE + MBEDTLS_CTR_DRBG_BLOCKSIZE ) /**< The seed length, calculated as (counter + AES key). */
  91. /**
  92. * \name SECTION: Module settings
  93. *
  94. * The configuration options you can set for this module are in this section.
  95. * Either change them in config.h or define them using the compiler command
  96. * line.
  97. * \{
  98. */
  99. /** \def MBEDTLS_CTR_DRBG_ENTROPY_LEN
  100. *
  101. * \brief The amount of entropy used per seed by default, in bytes.
  102. */
  103. #if !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN)
  104. #if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256)
  105. /** This is 48 bytes because the entropy module uses SHA-512
  106. * (\c MBEDTLS_ENTROPY_FORCE_SHA256 is disabled).
  107. */
  108. #define MBEDTLS_CTR_DRBG_ENTROPY_LEN 48
  109. #else /* defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256) */
  110. /** This is 32 bytes because the entropy module uses SHA-256
  111. * (the SHA512 module is disabled or
  112. * \c MBEDTLS_ENTROPY_FORCE_SHA256 is enabled).
  113. */
  114. #if !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
  115. /** \warning To achieve a 256-bit security strength, you must pass a nonce
  116. * to mbedtls_ctr_drbg_seed().
  117. */
  118. #endif /* !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY) */
  119. #define MBEDTLS_CTR_DRBG_ENTROPY_LEN 32
  120. #endif /* defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256) */
  121. #endif /* !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN) */
  122. #if !defined(MBEDTLS_CTR_DRBG_RESEED_INTERVAL)
  123. #define MBEDTLS_CTR_DRBG_RESEED_INTERVAL 10000
  124. /**< The interval before reseed is performed by default. */
  125. #endif
  126. #if !defined(MBEDTLS_CTR_DRBG_MAX_INPUT)
  127. #define MBEDTLS_CTR_DRBG_MAX_INPUT 256
  128. /**< The maximum number of additional input Bytes. */
  129. #endif
  130. #if !defined(MBEDTLS_CTR_DRBG_MAX_REQUEST)
  131. #define MBEDTLS_CTR_DRBG_MAX_REQUEST 1024
  132. /**< The maximum number of requested Bytes per call. */
  133. #endif
  134. #if !defined(MBEDTLS_CTR_DRBG_MAX_SEED_INPUT)
  135. #define MBEDTLS_CTR_DRBG_MAX_SEED_INPUT 384
  136. /**< The maximum size of seed or reseed buffer in bytes. */
  137. #endif
  138. /* \} name SECTION: Module settings */
  139. #define MBEDTLS_CTR_DRBG_PR_OFF 0
  140. /**< Prediction resistance is disabled. */
  141. #define MBEDTLS_CTR_DRBG_PR_ON 1
  142. /**< Prediction resistance is enabled. */
  143. #ifdef __cplusplus
  144. extern "C" {
  145. #endif
  146. /**
  147. * \brief The CTR_DRBG context structure.
  148. */
  149. typedef struct mbedtls_ctr_drbg_context
  150. {
  151. unsigned char counter[16]; /*!< The counter (V). */
  152. int reseed_counter; /*!< The reseed counter. */
  153. int prediction_resistance; /*!< This determines whether prediction
  154. resistance is enabled, that is
  155. whether to systematically reseed before
  156. each random generation. */
  157. size_t entropy_len; /*!< The amount of entropy grabbed on each
  158. seed or reseed operation. */
  159. int reseed_interval; /*!< The reseed interval. */
  160. mbedtls_aes_context aes_ctx; /*!< The AES context. */
  161. /*
  162. * Callbacks (Entropy)
  163. */
  164. int (*f_entropy)(void *, unsigned char *, size_t);
  165. /*!< The entropy callback function. */
  166. void *p_entropy; /*!< The context for the entropy function. */
  167. #if defined(MBEDTLS_THREADING_C)
  168. mbedtls_threading_mutex_t mutex;
  169. #endif
  170. }
  171. mbedtls_ctr_drbg_context;
  172. /**
  173. * \brief This function initializes the CTR_DRBG context,
  174. * and prepares it for mbedtls_ctr_drbg_seed()
  175. * or mbedtls_ctr_drbg_free().
  176. *
  177. * \param ctx The CTR_DRBG context to initialize.
  178. */
  179. void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx );
  180. /**
  181. * \brief This function seeds and sets up the CTR_DRBG
  182. * entropy source for future reseeds.
  183. *
  184. * A typical choice for the \p f_entropy and \p p_entropy parameters is
  185. * to use the entropy module:
  186. * - \p f_entropy is mbedtls_entropy_func();
  187. * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
  188. * with mbedtls_entropy_init() (which registers the platform's default
  189. * entropy sources).
  190. *
  191. * The entropy length is #MBEDTLS_CTR_DRBG_ENTROPY_LEN by default.
  192. * You can override it by calling mbedtls_ctr_drbg_set_entropy_len().
  193. *
  194. * You can provide a personalization string in addition to the
  195. * entropy source, to make this instantiation as unique as possible.
  196. *
  197. * \note The _seed_material_ value passed to the derivation
  198. * function in the CTR_DRBG Instantiate Process
  199. * described in NIST SP 800-90A §10.2.1.3.2
  200. * is the concatenation of the string obtained from
  201. * calling \p f_entropy and the \p custom string.
  202. * The origin of the nonce depends on the value of
  203. * the entropy length relative to the security strength.
  204. * - If the entropy length is at least 1.5 times the
  205. * security strength then the nonce is taken from the
  206. * string obtained with \p f_entropy.
  207. * - If the entropy length is less than the security
  208. * strength, then the nonce is taken from \p custom.
  209. * In this case, for compliance with SP 800-90A,
  210. * you must pass a unique value of \p custom at
  211. * each invocation. See SP 800-90A §8.6.7 for more
  212. * details.
  213. */
  214. #if MBEDTLS_CTR_DRBG_ENTROPY_LEN < MBEDTLS_CTR_DRBG_KEYSIZE * 3 / 2
  215. /** \warning When #MBEDTLS_CTR_DRBG_ENTROPY_LEN is less than
  216. * #MBEDTLS_CTR_DRBG_KEYSIZE * 3 / 2, to achieve the
  217. * maximum security strength permitted by CTR_DRBG,
  218. * you must pass a value of \p custom that is a nonce:
  219. * this value must never be repeated in subsequent
  220. * runs of the same application or on a different
  221. * device.
  222. */
  223. #endif
  224. /**
  225. * \param ctx The CTR_DRBG context to seed.
  226. * It must have been initialized with
  227. * mbedtls_ctr_drbg_init().
  228. * After a successful call to mbedtls_ctr_drbg_seed(),
  229. * you may not call mbedtls_ctr_drbg_seed() again on
  230. * the same context unless you call
  231. * mbedtls_ctr_drbg_free() and mbedtls_ctr_drbg_init()
  232. * again first.
  233. * \param f_entropy The entropy callback, taking as arguments the
  234. * \p p_entropy context, the buffer to fill, and the
  235. * length of the buffer.
  236. * \p f_entropy is always called with a buffer size
  237. * equal to the entropy length.
  238. * \param p_entropy The entropy context to pass to \p f_entropy.
  239. * \param custom The personalization string.
  240. * This can be \c NULL, in which case the personalization
  241. * string is empty regardless of the value of \p len.
  242. * \param len The length of the personalization string.
  243. * This must be at most
  244. * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT
  245. * - #MBEDTLS_CTR_DRBG_ENTROPY_LEN.
  246. *
  247. * \return \c 0 on success.
  248. * \return #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on failure.
  249. */
  250. int mbedtls_ctr_drbg_seed( mbedtls_ctr_drbg_context *ctx,
  251. int (*f_entropy)(void *, unsigned char *, size_t),
  252. void *p_entropy,
  253. const unsigned char *custom,
  254. size_t len );
  255. /**
  256. * \brief This function clears CTR_CRBG context data.
  257. *
  258. * \param ctx The CTR_DRBG context to clear.
  259. */
  260. void mbedtls_ctr_drbg_free( mbedtls_ctr_drbg_context *ctx );
  261. /**
  262. * \brief This function turns prediction resistance on or off.
  263. * The default value is off.
  264. *
  265. * \note If enabled, entropy is gathered at the beginning of
  266. * every call to mbedtls_ctr_drbg_random_with_add()
  267. * or mbedtls_ctr_drbg_random().
  268. * Only use this if your entropy source has sufficient
  269. * throughput.
  270. *
  271. * \param ctx The CTR_DRBG context.
  272. * \param resistance #MBEDTLS_CTR_DRBG_PR_ON or #MBEDTLS_CTR_DRBG_PR_OFF.
  273. */
  274. void mbedtls_ctr_drbg_set_prediction_resistance( mbedtls_ctr_drbg_context *ctx,
  275. int resistance );
  276. /**
  277. * \brief This function sets the amount of entropy grabbed on each
  278. * seed or reseed.
  279. *
  280. * The default value is #MBEDTLS_CTR_DRBG_ENTROPY_LEN.
  281. *
  282. * \note The security strength of CTR_DRBG is bounded by the
  283. * entropy length. Thus:
  284. * - When using AES-256
  285. * (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is disabled,
  286. * which is the default),
  287. * \p len must be at least 32 (in bytes)
  288. * to achieve a 256-bit strength.
  289. * - When using AES-128
  290. * (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled)
  291. * \p len must be at least 16 (in bytes)
  292. * to achieve a 128-bit strength.
  293. *
  294. * \param ctx The CTR_DRBG context.
  295. * \param len The amount of entropy to grab, in bytes.
  296. * This must be at most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
  297. */
  298. void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx,
  299. size_t len );
  300. /**
  301. * \brief This function sets the reseed interval.
  302. *
  303. * The reseed interval is the number of calls to mbedtls_ctr_drbg_random()
  304. * or mbedtls_ctr_drbg_random_with_add() after which the entropy function
  305. * is called again.
  306. *
  307. * The default value is #MBEDTLS_CTR_DRBG_RESEED_INTERVAL.
  308. *
  309. * \param ctx The CTR_DRBG context.
  310. * \param interval The reseed interval.
  311. */
  312. void mbedtls_ctr_drbg_set_reseed_interval( mbedtls_ctr_drbg_context *ctx,
  313. int interval );
  314. /**
  315. * \brief This function reseeds the CTR_DRBG context, that is
  316. * extracts data from the entropy source.
  317. *
  318. * \param ctx The CTR_DRBG context.
  319. * \param additional Additional data to add to the state. Can be \c NULL.
  320. * \param len The length of the additional data.
  321. * This must be less than
  322. * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - \c entropy_len
  323. * where \c entropy_len is the entropy length
  324. * configured for the context.
  325. *
  326. * \return \c 0 on success.
  327. * \return #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on failure.
  328. */
  329. int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx,
  330. const unsigned char *additional, size_t len );
  331. /**
  332. * \brief This function updates the state of the CTR_DRBG context.
  333. *
  334. * \param ctx The CTR_DRBG context.
  335. * \param additional The data to update the state with. This must not be
  336. * \c NULL unless \p add_len is \c 0.
  337. * \param add_len Length of \p additional in bytes. This must be at
  338. * most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
  339. *
  340. * \return \c 0 on success.
  341. * \return #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if
  342. * \p add_len is more than
  343. * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
  344. * \return An error from the underlying AES cipher on failure.
  345. */
  346. int mbedtls_ctr_drbg_update_ret( mbedtls_ctr_drbg_context *ctx,
  347. const unsigned char *additional,
  348. size_t add_len );
  349. /**
  350. * \brief This function updates a CTR_DRBG instance with additional
  351. * data and uses it to generate random data.
  352. *
  353. * This function automatically reseeds if the reseed counter is exceeded
  354. * or prediction resistance is enabled.
  355. *
  356. * \param p_rng The CTR_DRBG context. This must be a pointer to a
  357. * #mbedtls_ctr_drbg_context structure.
  358. * \param output The buffer to fill.
  359. * \param output_len The length of the buffer in bytes.
  360. * \param additional Additional data to update. Can be \c NULL, in which
  361. * case the additional data is empty regardless of
  362. * the value of \p add_len.
  363. * \param add_len The length of the additional data
  364. * if \p additional is not \c NULL.
  365. * This must be less than #MBEDTLS_CTR_DRBG_MAX_INPUT
  366. * and less than
  367. * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - \c entropy_len
  368. * where \c entropy_len is the entropy length
  369. * configured for the context.
  370. *
  371. * \return \c 0 on success.
  372. * \return #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or
  373. * #MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG on failure.
  374. */
  375. int mbedtls_ctr_drbg_random_with_add( void *p_rng,
  376. unsigned char *output, size_t output_len,
  377. const unsigned char *additional, size_t add_len );
  378. /**
  379. * \brief This function uses CTR_DRBG to generate random data.
  380. *
  381. * This function automatically reseeds if the reseed counter is exceeded
  382. * or prediction resistance is enabled.
  383. *
  384. *
  385. * \param p_rng The CTR_DRBG context. This must be a pointer to a
  386. * #mbedtls_ctr_drbg_context structure.
  387. * \param output The buffer to fill.
  388. * \param output_len The length of the buffer in bytes.
  389. *
  390. * \return \c 0 on success.
  391. * \return #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or
  392. * #MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG on failure.
  393. */
  394. int mbedtls_ctr_drbg_random( void *p_rng,
  395. unsigned char *output, size_t output_len );
  396. #if ! defined(MBEDTLS_DEPRECATED_REMOVED)
  397. #if defined(MBEDTLS_DEPRECATED_WARNING)
  398. #define MBEDTLS_DEPRECATED __attribute__((deprecated))
  399. #else
  400. #define MBEDTLS_DEPRECATED
  401. #endif
  402. /**
  403. * \brief This function updates the state of the CTR_DRBG context.
  404. *
  405. * \deprecated Superseded by mbedtls_ctr_drbg_update_ret()
  406. * in 2.16.0.
  407. *
  408. * \note If \p add_len is greater than
  409. * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT, only the first
  410. * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT Bytes are used.
  411. * The remaining Bytes are silently discarded.
  412. *
  413. * \param ctx The CTR_DRBG context.
  414. * \param additional The data to update the state with.
  415. * \param add_len Length of \p additional data.
  416. */
  417. MBEDTLS_DEPRECATED void mbedtls_ctr_drbg_update(
  418. mbedtls_ctr_drbg_context *ctx,
  419. const unsigned char *additional,
  420. size_t add_len );
  421. #undef MBEDTLS_DEPRECATED
  422. #endif /* !MBEDTLS_DEPRECATED_REMOVED */
  423. #if defined(MBEDTLS_FS_IO)
  424. /**
  425. * \brief This function writes a seed file.
  426. *
  427. * \param ctx The CTR_DRBG context.
  428. * \param path The name of the file.
  429. *
  430. * \return \c 0 on success.
  431. * \return #MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR on file error.
  432. * \return #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on reseed
  433. * failure.
  434. */
  435. int mbedtls_ctr_drbg_write_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path );
  436. /**
  437. * \brief This function reads and updates a seed file. The seed
  438. * is added to this instance.
  439. *
  440. * \param ctx The CTR_DRBG context.
  441. * \param path The name of the file.
  442. *
  443. * \return \c 0 on success.
  444. * \return #MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR on file error.
  445. * \return #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on
  446. * reseed failure.
  447. * \return #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if the existing
  448. * seed file is too large.
  449. */
  450. int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path );
  451. #endif /* MBEDTLS_FS_IO */
  452. #if defined(MBEDTLS_SELF_TEST)
  453. /**
  454. * \brief The CTR_DRBG checkup routine.
  455. *
  456. * \return \c 0 on success.
  457. * \return \c 1 on failure.
  458. */
  459. int mbedtls_ctr_drbg_self_test( int verbose );
  460. #endif /* MBEDTLS_SELF_TEST */
  461. /* Internal functions (do not call directly) */
  462. int mbedtls_ctr_drbg_seed_entropy_len( mbedtls_ctr_drbg_context *,
  463. int (*)(void *, unsigned char *, size_t), void *,
  464. const unsigned char *, size_t, size_t );
  465. #ifdef __cplusplus
  466. }
  467. #endif
  468. #endif /* ctr_drbg.h */