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diff --git a/include/mbedtls/ctr_drbg.h b/include/mbedtls/ctr_drbg.h
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+/**
+ * \file ctr_drbg.h
+ *
+ * \brief    This file contains definitions and functions for the
+ *           CTR_DRBG pseudorandom generator.
+ *
+ * CTR_DRBG is a standardized way of building a PRNG from a block-cipher
+ * in counter mode operation, as defined in <em>NIST SP 800-90A:
+ * Recommendation for Random Number Generation Using Deterministic Random
+ * Bit Generators</em>.
+ *
+ * The Mbed TLS implementation of CTR_DRBG uses AES-256 (default) or AES-128
+ * (if \c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled at compile time)
+ * as the underlying block cipher, with a derivation function.
+ *
+ * The security strength as defined in NIST SP 800-90A is
+ * 128 bits when AES-128 is used (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY enabled)
+ * and 256 bits otherwise, provided that #MBEDTLS_CTR_DRBG_ENTROPY_LEN is
+ * kept at its default value (and not overridden in mbedtls_config.h) and that the
+ * DRBG instance is set up with default parameters.
+ * See the documentation of mbedtls_ctr_drbg_seed() for more
+ * information.
+ */
+/*
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#ifndef MBEDTLS_CTR_DRBG_H
+#define MBEDTLS_CTR_DRBG_H
+#include "mbedtls/private_access.h"
+
+#include "mbedtls/build_info.h"
+
+#include "mbedtls/aes.h"
+#include "entropy.h"
+
+#if defined(MBEDTLS_THREADING_C)
+#include "mbedtls/threading.h"
+#endif
+
+/** The entropy source failed. */
+#define MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED        -0x0034
+/** The requested random buffer length is too big. */
+#define MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG              -0x0036
+/** The input (entropy + additional data) is too large. */
+#define MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG                -0x0038
+/** Read or write error in file. */
+#define MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR                -0x003A
+
+#define MBEDTLS_CTR_DRBG_BLOCKSIZE          16 /**< The block size used by the cipher. */
+
+#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
+#define MBEDTLS_CTR_DRBG_KEYSIZE            16
+/**< The key size in bytes used by the cipher.
+ *
+ * Compile-time choice: 16 bytes (128 bits)
+ * because #MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled.
+ */
+#else
+#define MBEDTLS_CTR_DRBG_KEYSIZE            32
+/**< The key size in bytes used by the cipher.
+ *
+ * Compile-time choice: 32 bytes (256 bits)
+ * because \c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is disabled.
+ */
+#endif
+
+#define MBEDTLS_CTR_DRBG_KEYBITS            (MBEDTLS_CTR_DRBG_KEYSIZE * 8)   /**< The key size for the DRBG operation, in bits. */
+#define MBEDTLS_CTR_DRBG_SEEDLEN            (MBEDTLS_CTR_DRBG_KEYSIZE + MBEDTLS_CTR_DRBG_BLOCKSIZE)   /**< The seed length, calculated as (counter + AES key). */
+
+/**
+ * \name SECTION: Module settings
+ *
+ * The configuration options you can set for this module are in this section.
+ * Either change them in mbedtls_config.h or define them using the compiler command
+ * line.
+ * \{
+ */
+
+/** \def MBEDTLS_CTR_DRBG_ENTROPY_LEN
+ *
+ * \brief The amount of entropy used per seed by default, in bytes.
+ */
+#if !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN)
+#if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
+/** This is 48 bytes because the entropy module uses SHA-512.
+ */
+#define MBEDTLS_CTR_DRBG_ENTROPY_LEN        48
+
+#else /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
+
+/** This is 32 bytes because the entropy module uses SHA-256.
+ */
+#if !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
+/** \warning To achieve a 256-bit security strength, you must pass a nonce
+ *           to mbedtls_ctr_drbg_seed().
+ */
+#endif /* !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY) */
+#define MBEDTLS_CTR_DRBG_ENTROPY_LEN        32
+#endif /* MBEDTLS_ENTROPY_SHA512_ACCUMULATOR */
+#endif /* !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN) */
+
+#if !defined(MBEDTLS_CTR_DRBG_RESEED_INTERVAL)
+#define MBEDTLS_CTR_DRBG_RESEED_INTERVAL    10000
+/**< The interval before reseed is performed by default. */
+#endif
+
+#if !defined(MBEDTLS_CTR_DRBG_MAX_INPUT)
+#define MBEDTLS_CTR_DRBG_MAX_INPUT          256
+/**< The maximum number of additional input Bytes. */
+#endif
+
+#if !defined(MBEDTLS_CTR_DRBG_MAX_REQUEST)
+#define MBEDTLS_CTR_DRBG_MAX_REQUEST        1024
+/**< The maximum number of requested Bytes per call. */
+#endif
+
+#if !defined(MBEDTLS_CTR_DRBG_MAX_SEED_INPUT)
+#define MBEDTLS_CTR_DRBG_MAX_SEED_INPUT     384
+/**< The maximum size of seed or reseed buffer in bytes. */
+#endif
+
+/** \} name SECTION: Module settings */
+
+#define MBEDTLS_CTR_DRBG_PR_OFF             0
+/**< Prediction resistance is disabled. */
+#define MBEDTLS_CTR_DRBG_PR_ON              1
+/**< Prediction resistance is enabled. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#if MBEDTLS_CTR_DRBG_ENTROPY_LEN >= MBEDTLS_CTR_DRBG_KEYSIZE * 3 / 2
+/** The default length of the nonce read from the entropy source.
+ *
+ * This is \c 0 because a single read from the entropy source is sufficient
+ * to include a nonce.
+ * See the documentation of mbedtls_ctr_drbg_seed() for more information.
+ */
+#define MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN 0
+#else
+/** The default length of the nonce read from the entropy source.
+ *
+ * This is half of the default entropy length because a single read from
+ * the entropy source does not provide enough material to form a nonce.
+ * See the documentation of mbedtls_ctr_drbg_seed() for more information.
+ */
+#define MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN (MBEDTLS_CTR_DRBG_ENTROPY_LEN + 1) / 2
+#endif
+
+/**
+ * \brief          The CTR_DRBG context structure.
+ */
+typedef struct mbedtls_ctr_drbg_context {
+    unsigned char MBEDTLS_PRIVATE(counter)[16];  /*!< The counter (V). */
+    int MBEDTLS_PRIVATE(reseed_counter);         /*!< The reseed counter.
+                                                  * This is the number of requests that have
+                                                  * been made since the last (re)seeding,
+                                                  * minus one.
+                                                  * Before the initial seeding, this field
+                                                  * contains the amount of entropy in bytes
+                                                  * to use as a nonce for the initial seeding,
+                                                  * or -1 if no nonce length has been explicitly
+                                                  * set (see mbedtls_ctr_drbg_set_nonce_len()).
+                                                  */
+    int MBEDTLS_PRIVATE(prediction_resistance);  /*!< This determines whether prediction
+                                                    resistance is enabled, that is
+                                                    whether to systematically reseed before
+                                                    each random generation. */
+    size_t MBEDTLS_PRIVATE(entropy_len);         /*!< The amount of entropy grabbed on each
+                                                    seed or reseed operation, in bytes. */
+    int MBEDTLS_PRIVATE(reseed_interval);        /*!< The reseed interval.
+                                                  * This is the maximum number of requests
+                                                  * that can be made between reseedings. */
+
+    mbedtls_aes_context MBEDTLS_PRIVATE(aes_ctx);        /*!< The AES context. */
+
+    /*
+     * Callbacks (Entropy)
+     */
+    int(*MBEDTLS_PRIVATE(f_entropy))(void *, unsigned char *, size_t);
+    /*!< The entropy callback function. */
+
+    void *MBEDTLS_PRIVATE(p_entropy);            /*!< The context for the entropy function. */
+
+#if defined(MBEDTLS_THREADING_C)
+    /* Invariant: the mutex is initialized if and only if f_entropy != NULL.
+     * This means that the mutex is initialized during the initial seeding
+     * in mbedtls_ctr_drbg_seed() and freed in mbedtls_ctr_drbg_free().
+     *
+     * Note that this invariant may change without notice. Do not rely on it
+     * and do not access the mutex directly in application code.
+     */
+    mbedtls_threading_mutex_t MBEDTLS_PRIVATE(mutex);
+#endif
+}
+mbedtls_ctr_drbg_context;
+
+/**
+ * \brief               This function initializes the CTR_DRBG context,
+ *                      and prepares it for mbedtls_ctr_drbg_seed()
+ *                      or mbedtls_ctr_drbg_free().
+ *
+ * \note                The reseed interval is
+ *                      #MBEDTLS_CTR_DRBG_RESEED_INTERVAL by default.
+ *                      You can override it by calling
+ *                      mbedtls_ctr_drbg_set_reseed_interval().
+ *
+ * \param ctx           The CTR_DRBG context to initialize.
+ */
+void mbedtls_ctr_drbg_init(mbedtls_ctr_drbg_context *ctx);
+
+/**
+ * \brief               This function seeds and sets up the CTR_DRBG
+ *                      entropy source for future reseeds.
+ *
+ * A typical choice for the \p f_entropy and \p p_entropy parameters is
+ * to use the entropy module:
+ * - \p f_entropy is mbedtls_entropy_func();
+ * - \p p_entropy is an instance of ::mbedtls_entropy_context initialized
+ *   with mbedtls_entropy_init() (which registers the platform's default
+ *   entropy sources).
+ *
+ * The entropy length is #MBEDTLS_CTR_DRBG_ENTROPY_LEN by default.
+ * You can override it by calling mbedtls_ctr_drbg_set_entropy_len().
+ *
+ * The entropy nonce length is:
+ * - \c 0 if the entropy length is at least 3/2 times the entropy length,
+ *   which guarantees that the security strength is the maximum permitted
+ *   by the key size and entropy length according to NIST SP 800-90A §10.2.1;
+ * - Half the entropy length otherwise.
+ * You can override it by calling mbedtls_ctr_drbg_set_nonce_len().
+ * With the default entropy length, the entropy nonce length is
+ * #MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN.
+ *
+ * You can provide a nonce and personalization string in addition to the
+ * entropy source, to make this instantiation as unique as possible.
+ * See SP 800-90A §8.6.7 for more details about nonces.
+ *
+ * The _seed_material_ value passed to the derivation function in
+ * the CTR_DRBG Instantiate Process described in NIST SP 800-90A §10.2.1.3.2
+ * is the concatenation of the following strings:
+ * - A string obtained by calling \p f_entropy function for the entropy
+ *   length.
+ */
+#if MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN == 0
+/**
+ * - If mbedtls_ctr_drbg_set_nonce_len() has been called, a string
+ *   obtained by calling \p f_entropy function for the specified length.
+ */
+#else
+/**
+ * - A string obtained by calling \p f_entropy function for the entropy nonce
+ *   length. If the entropy nonce length is \c 0, this function does not
+ *   make a second call to \p f_entropy.
+ */
+#endif
+#if defined(MBEDTLS_THREADING_C)
+/**
+ * \note                When Mbed TLS is built with threading support,
+ *                      after this function returns successfully,
+ *                      it is safe to call mbedtls_ctr_drbg_random()
+ *                      from multiple threads. Other operations, including
+ *                      reseeding, are not thread-safe.
+ */
+#endif /* MBEDTLS_THREADING_C */
+/**
+ * - The \p custom string.
+ *
+ * \note                To achieve the nominal security strength permitted
+ *                      by CTR_DRBG, the entropy length must be:
+ *                      - at least 16 bytes for a 128-bit strength
+ *                      (maximum achievable strength when using AES-128);
+ *                      - at least 32 bytes for a 256-bit strength
+ *                      (maximum achievable strength when using AES-256).
+ *
+ *                      In addition, if you do not pass a nonce in \p custom,
+ *                      the sum of the entropy length
+ *                      and the entropy nonce length must be:
+ *                      - at least 24 bytes for a 128-bit strength
+ *                      (maximum achievable strength when using AES-128);
+ *                      - at least 48 bytes for a 256-bit strength
+ *                      (maximum achievable strength when using AES-256).
+ *
+ * \param ctx           The CTR_DRBG context to seed.
+ *                      It must have been initialized with
+ *                      mbedtls_ctr_drbg_init().
+ *                      After a successful call to mbedtls_ctr_drbg_seed(),
+ *                      you may not call mbedtls_ctr_drbg_seed() again on
+ *                      the same context unless you call
+ *                      mbedtls_ctr_drbg_free() and mbedtls_ctr_drbg_init()
+ *                      again first.
+ *                      After a failed call to mbedtls_ctr_drbg_seed(),
+ *                      you must call mbedtls_ctr_drbg_free().
+ * \param f_entropy     The entropy callback, taking as arguments the
+ *                      \p p_entropy context, the buffer to fill, and the
+ *                      length of the buffer.
+ *                      \p f_entropy is always called with a buffer size
+ *                      less than or equal to the entropy length.
+ * \param p_entropy     The entropy context to pass to \p f_entropy.
+ * \param custom        The personalization string.
+ *                      This can be \c NULL, in which case the personalization
+ *                      string is empty regardless of the value of \p len.
+ * \param len           The length of the personalization string.
+ *                      This must be at most
+ *                      #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT
+ *                      - #MBEDTLS_CTR_DRBG_ENTROPY_LEN.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on failure.
+ */
+int mbedtls_ctr_drbg_seed(mbedtls_ctr_drbg_context *ctx,
+                          int (*f_entropy)(void *, unsigned char *, size_t),
+                          void *p_entropy,
+                          const unsigned char *custom,
+                          size_t len);
+
+/**
+ * \brief               This function resets CTR_DRBG context to the state immediately
+ *                      after initial call of mbedtls_ctr_drbg_init().
+ *
+ * \param ctx           The CTR_DRBG context to clear.
+ */
+void mbedtls_ctr_drbg_free(mbedtls_ctr_drbg_context *ctx);
+
+/**
+ * \brief               This function turns prediction resistance on or off.
+ *                      The default value is off.
+ *
+ * \note                If enabled, entropy is gathered at the beginning of
+ *                      every call to mbedtls_ctr_drbg_random_with_add()
+ *                      or mbedtls_ctr_drbg_random().
+ *                      Only use this if your entropy source has sufficient
+ *                      throughput.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param resistance    #MBEDTLS_CTR_DRBG_PR_ON or #MBEDTLS_CTR_DRBG_PR_OFF.
+ */
+void mbedtls_ctr_drbg_set_prediction_resistance(mbedtls_ctr_drbg_context *ctx,
+                                                int resistance);
+
+/**
+ * \brief               This function sets the amount of entropy grabbed on each
+ *                      seed or reseed.
+ *
+ * The default value is #MBEDTLS_CTR_DRBG_ENTROPY_LEN.
+ *
+ * \note                The security strength of CTR_DRBG is bounded by the
+ *                      entropy length. Thus:
+ *                      - When using AES-256
+ *                        (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is disabled,
+ *                        which is the default),
+ *                        \p len must be at least 32 (in bytes)
+ *                        to achieve a 256-bit strength.
+ *                      - When using AES-128
+ *                        (\c MBEDTLS_CTR_DRBG_USE_128_BIT_KEY is enabled)
+ *                        \p len must be at least 16 (in bytes)
+ *                        to achieve a 128-bit strength.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param len           The amount of entropy to grab, in bytes.
+ *                      This must be at most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT
+ *                      and at most the maximum length accepted by the
+ *                      entropy function that is set in the context.
+ */
+void mbedtls_ctr_drbg_set_entropy_len(mbedtls_ctr_drbg_context *ctx,
+                                      size_t len);
+
+/**
+ * \brief               This function sets the amount of entropy grabbed
+ *                      as a nonce for the initial seeding.
+ *
+ * Call this function before calling mbedtls_ctr_drbg_seed() to read
+ * a nonce from the entropy source during the initial seeding.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param len           The amount of entropy to grab for the nonce, in bytes.
+ *                      This must be at most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT
+ *                      and at most the maximum length accepted by the
+ *                      entropy function that is set in the context.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if \p len is
+ *                      more than #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED
+ *                      if the initial seeding has already taken place.
+ */
+int mbedtls_ctr_drbg_set_nonce_len(mbedtls_ctr_drbg_context *ctx,
+                                   size_t len);
+
+/**
+ * \brief               This function sets the reseed interval.
+ *
+ * The reseed interval is the number of calls to mbedtls_ctr_drbg_random()
+ * or mbedtls_ctr_drbg_random_with_add() after which the entropy function
+ * is called again.
+ *
+ * The default value is #MBEDTLS_CTR_DRBG_RESEED_INTERVAL.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param interval      The reseed interval.
+ */
+void mbedtls_ctr_drbg_set_reseed_interval(mbedtls_ctr_drbg_context *ctx,
+                                          int interval);
+
+/**
+ * \brief               This function reseeds the CTR_DRBG context, that is
+ *                      extracts data from the entropy source.
+ *
+ * \note                This function is not thread-safe. It is not safe
+ *                      to call this function if another thread might be
+ *                      concurrently obtaining random numbers from the same
+ *                      context or updating or reseeding the same context.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param additional    Additional data to add to the state. Can be \c NULL.
+ * \param len           The length of the additional data.
+ *                      This must be less than
+ *                      #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - \c entropy_len
+ *                      where \c entropy_len is the entropy length
+ *                      configured for the context.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on failure.
+ */
+int mbedtls_ctr_drbg_reseed(mbedtls_ctr_drbg_context *ctx,
+                            const unsigned char *additional, size_t len);
+
+/**
+ * \brief              This function updates the state of the CTR_DRBG context.
+ *
+ * \note                This function is not thread-safe. It is not safe
+ *                      to call this function if another thread might be
+ *                      concurrently obtaining random numbers from the same
+ *                      context or updating or reseeding the same context.
+ *
+ * \param ctx          The CTR_DRBG context.
+ * \param additional   The data to update the state with. This must not be
+ *                     \c NULL unless \p add_len is \c 0.
+ * \param add_len      Length of \p additional in bytes. This must be at
+ *                     most #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
+ *
+ * \return             \c 0 on success.
+ * \return             #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if
+ *                     \p add_len is more than
+ *                     #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT.
+ * \return             An error from the underlying AES cipher on failure.
+ */
+int mbedtls_ctr_drbg_update(mbedtls_ctr_drbg_context *ctx,
+                            const unsigned char *additional,
+                            size_t add_len);
+
+/**
+ * \brief   This function updates a CTR_DRBG instance with additional
+ *          data and uses it to generate random data.
+ *
+ * This function automatically reseeds if the reseed counter is exceeded
+ * or prediction resistance is enabled.
+ *
+ * \note                This function is not thread-safe. It is not safe
+ *                      to call this function if another thread might be
+ *                      concurrently obtaining random numbers from the same
+ *                      context or updating or reseeding the same context.
+ *
+ * \param p_rng         The CTR_DRBG context. This must be a pointer to a
+ *                      #mbedtls_ctr_drbg_context structure.
+ * \param output        The buffer to fill.
+ * \param output_len    The length of the buffer in bytes.
+ * \param additional    Additional data to update. Can be \c NULL, in which
+ *                      case the additional data is empty regardless of
+ *                      the value of \p add_len.
+ * \param add_len       The length of the additional data
+ *                      if \p additional is not \c NULL.
+ *                      This must be less than #MBEDTLS_CTR_DRBG_MAX_INPUT
+ *                      and less than
+ *                      #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT - \c entropy_len
+ *                      where \c entropy_len is the entropy length
+ *                      configured for the context.
+ *
+ * \return    \c 0 on success.
+ * \return    #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or
+ *            #MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG on failure.
+ */
+int mbedtls_ctr_drbg_random_with_add(void *p_rng,
+                                     unsigned char *output, size_t output_len,
+                                     const unsigned char *additional, size_t add_len);
+
+/**
+ * \brief   This function uses CTR_DRBG to generate random data.
+ *
+ * This function automatically reseeds if the reseed counter is exceeded
+ * or prediction resistance is enabled.
+ */
+#if defined(MBEDTLS_THREADING_C)
+/**
+ * \note                When Mbed TLS is built with threading support,
+ *                      it is safe to call mbedtls_ctr_drbg_random()
+ *                      from multiple threads. Other operations, including
+ *                      reseeding, are not thread-safe.
+ */
+#endif /* MBEDTLS_THREADING_C */
+/**
+ * \param p_rng         The CTR_DRBG context. This must be a pointer to a
+ *                      #mbedtls_ctr_drbg_context structure.
+ * \param output        The buffer to fill.
+ * \param output_len    The length of the buffer in bytes.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED or
+ *                      #MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG on failure.
+ */
+int mbedtls_ctr_drbg_random(void *p_rng,
+                            unsigned char *output, size_t output_len);
+
+#if defined(MBEDTLS_FS_IO)
+/**
+ * \brief               This function writes a seed file.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param path          The name of the file.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR on file error.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on reseed
+ *                      failure.
+ */
+int mbedtls_ctr_drbg_write_seed_file(mbedtls_ctr_drbg_context *ctx, const char *path);
+
+/**
+ * \brief               This function reads and updates a seed file. The seed
+ *                      is added to this instance.
+ *
+ * \param ctx           The CTR_DRBG context.
+ * \param path          The name of the file.
+ *
+ * \return              \c 0 on success.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR on file error.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED on
+ *                      reseed failure.
+ * \return              #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG if the existing
+ *                      seed file is too large.
+ */
+int mbedtls_ctr_drbg_update_seed_file(mbedtls_ctr_drbg_context *ctx, const char *path);
+#endif /* MBEDTLS_FS_IO */
+
+#if defined(MBEDTLS_SELF_TEST)
+
+/**
+ * \brief               The CTR_DRBG checkup routine.
+ *
+ * \return              \c 0 on success.
+ * \return              \c 1 on failure.
+ */
+int mbedtls_ctr_drbg_self_test(int verbose);
+
+#endif /* MBEDTLS_SELF_TEST */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ctr_drbg.h */