--- /dev/null
+/**
+ * \file ctr_drbg.h
+ *
+ * \brief This file contains CTR_DRBG definitions and functions.
+ *
+ * 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 as the underlying
+ * block cipher.
+ */
+/*
+ * Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
+ * SPDX-License-Identifier: GPL-2.0
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * This file is part of Mbed TLS (https://tls.mbed.org)
+ */
+
+#ifndef MBEDTLS_CTR_DRBG_H
+#define MBEDTLS_CTR_DRBG_H
+
+#include "aes.h"
+
+#if defined(MBEDTLS_THREADING_C)
+#include "threading.h"
+#endif
+
+#define MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED -0x0034 /**< The entropy source failed. */
+#define MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG -0x0036 /**< The requested random buffer length is too big. */
+#define MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG -0x0038 /**< The input (entropy + additional data) is too large. */
+#define MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR -0x003A /**< Read or write error in file. */
+
+#define MBEDTLS_CTR_DRBG_BLOCKSIZE 16 /**< The block size used by the cipher. */
+#define MBEDTLS_CTR_DRBG_KEYSIZE 32 /**< The key size used by the cipher. */
+#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 config.h or define them using the compiler command
+ * line.
+ * \{
+ */
+
+#if !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN)
+#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256)
+#define MBEDTLS_CTR_DRBG_ENTROPY_LEN 48
+/**< The amount of entropy used per seed by default:
+ * <ul><li>48 with SHA-512.</li>
+ * <li>32 with SHA-256.</li></ul>
+ */
+#else
+#define MBEDTLS_CTR_DRBG_ENTROPY_LEN 32
+/**< Amount of entropy used per seed by default:
+ * <ul><li>48 with SHA-512.</li>
+ * <li>32 with SHA-256.</li></ul>
+ */
+#endif
+#endif
+
+#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. */
+#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
+
+/**
+ * \brief The CTR_DRBG context structure.
+ */
+typedef struct mbedtls_ctr_drbg_context
+{
+ unsigned char counter[16]; /*!< The counter (V). */
+ int reseed_counter; /*!< The reseed counter. */
+ int prediction_resistance; /*!< This determines whether prediction
+ resistance is enabled, that is
+ whether to systematically reseed before
+ each random generation. */
+ size_t entropy_len; /*!< The amount of entropy grabbed on each
+ seed or reseed operation. */
+ int reseed_interval; /*!< The reseed interval. */
+
+ mbedtls_aes_context aes_ctx; /*!< The AES context. */
+
+ /*
+ * Callbacks (Entropy)
+ */
+ int (*f_entropy)(void *, unsigned char *, size_t);
+ /*!< The entropy callback function. */
+
+ void *p_entropy; /*!< The context for the entropy function. */
+
+#if defined(MBEDTLS_THREADING_C)
+ mbedtls_threading_mutex_t 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().
+ *
+ * \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.
+ *
+ * \note Personalization data can be provided in addition to the more generic
+ * entropy source, to make this instantiation as unique as possible.
+ *
+ * \param ctx The CTR_DRBG context to seed.
+ * \param f_entropy The entropy callback, taking as arguments the
+ * \p p_entropy context, the buffer to fill, and the
+ length of the buffer.
+ * \param p_entropy The entropy context.
+ * \param custom Personalization data, that is device-specific
+ identifiers. Can be NULL.
+ * \param len The length of the personalization data.
+ *
+ * \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 clears CTR_CRBG context data.
+ *
+ * \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().
+ * 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.
+ *
+ * \param ctx The CTR_DRBG context.
+ * \param len The amount of entropy to grab.
+ */
+void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx,
+ size_t len );
+
+/**
+ * \brief This function sets the reseed interval.
+ * 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.
+ *
+ * \param ctx The CTR_DRBG context.
+ * \param additional Additional data to add to the state. Can be NULL.
+ * \param len The length of the additional data.
+ *
+ * \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 If \p add_len is greater than
+ * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT, only the first
+ * #MBEDTLS_CTR_DRBG_MAX_SEED_INPUT Bytes are used.
+ * The remaining Bytes are silently discarded.
+ *
+ * \param ctx The CTR_DRBG context.
+ * \param additional The data to update the state with.
+ * \param add_len Length of \p additional data.
+ *
+ */
+void 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.
+ *
+ * \note The function automatically reseeds if the reseed counter is exceeded.
+ *
+ * \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.
+ * \param additional Additional data to update. Can be NULL.
+ * \param add_len The length of the additional data.
+ *
+ * \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.
+ *
+ * \note The function automatically reseeds if the reseed counter is exceeded.
+ *
+ * \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.
+ *
+ * \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
+ * 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 or
+ * #MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG on failure.
+ */
+int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path );
+#endif /* MBEDTLS_FS_IO */
+
+/**
+ * \brief The CTR_DRBG checkup routine.
+ *
+ * \return \c 0 on success.
+ * \return \c 1 on failure.
+ */
+int mbedtls_ctr_drbg_self_test( int verbose );
+
+/* Internal functions (do not call directly) */
+int mbedtls_ctr_drbg_seed_entropy_len( mbedtls_ctr_drbg_context *,
+ int (*)(void *, unsigned char *, size_t), void *,
+ const unsigned char *, size_t, size_t );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* ctr_drbg.h */
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