Diff: include/mbedtls/hmac_drbg.h

Revision:

0:cdf462088d13

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/mbedtls/hmac_drbg.h	Thu Jan 05 00:18:44 2017 +0000
@@ -0,0 +1,299 @@
+/**
+ * \file hmac_drbg.h
+ *
+ * \brief HMAC_DRBG (NIST SP 800-90A)
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+#ifndef MBEDTLS_HMAC_DRBG_H
+#define MBEDTLS_HMAC_DRBG_H
+
+#include "md.h"
+
+#if defined(MBEDTLS_THREADING_C)
+#include "mbedtls/threading.h"
+#endif
+
+/*
+ * Error codes
+ */
+#define MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG              -0x0003  /**< Too many random requested in single call. */
+#define MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG                -0x0005  /**< Input too large (Entropy + additional). */
+#define MBEDTLS_ERR_HMAC_DRBG_FILE_IO_ERROR                -0x0007  /**< Read/write error in file. */
+#define MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED        -0x0009  /**< The entropy source failed. */
+
+/**
+ * \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 on the compiler command line.
+ * \{
+ */
+
+#if !defined(MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
+#define MBEDTLS_HMAC_DRBG_RESEED_INTERVAL   10000   /**< Interval before reseed is performed by default */
+#endif
+
+#if !defined(MBEDTLS_HMAC_DRBG_MAX_INPUT)
+#define MBEDTLS_HMAC_DRBG_MAX_INPUT         256     /**< Maximum number of additional input bytes */
+#endif
+
+#if !defined(MBEDTLS_HMAC_DRBG_MAX_REQUEST)
+#define MBEDTLS_HMAC_DRBG_MAX_REQUEST       1024    /**< Maximum number of requested bytes per call */
+#endif
+
+#if !defined(MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT)
+#define MBEDTLS_HMAC_DRBG_MAX_SEED_INPUT    384     /**< Maximum size of (re)seed buffer */
+#endif
+
+/* \} name SECTION: Module settings */
+
+#define MBEDTLS_HMAC_DRBG_PR_OFF   0   /**< No prediction resistance       */
+#define MBEDTLS_HMAC_DRBG_PR_ON    1   /**< Prediction resistance enabled  */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * HMAC_DRBG context.
+ */
+typedef struct
+{
+    /* Working state: the key K is not stored explicitely,
+     * but is implied by the HMAC context */
+    mbedtls_md_context_t md_ctx;                    /*!< HMAC context (inc. K)  */
+    unsigned char V[MBEDTLS_MD_MAX_SIZE];  /*!< V in the spec          */
+    int reseed_counter;                     /*!< reseed counter         */
+
+    /* Administrative state */
+    size_t entropy_len;         /*!< entropy bytes grabbed on each (re)seed */
+    int prediction_resistance;  /*!< enable prediction resistance (Automatic
+                                     reseed before every random generation) */
+    int reseed_interval;        /*!< reseed interval   */
+
+    /* Callbacks */
+    int (*f_entropy)(void *, unsigned char *, size_t); /*!< entropy function */
+    void *p_entropy;            /*!< context for the entropy function        */
+
+#if defined(MBEDTLS_THREADING_C)
+    mbedtls_threading_mutex_t mutex;
+#endif
+} mbedtls_hmac_drbg_context;
+
+/**
+ * \brief               HMAC_DRBG context initialization
+ *                      Makes the context ready for mbedtls_hmac_drbg_seed(),
+ *                      mbedtls_hmac_drbg_seed_buf() or
+ *                      mbedtls_hmac_drbg_free().
+ *
+ * \param ctx           HMAC_DRBG context to be initialized
+ */
+void mbedtls_hmac_drbg_init( mbedtls_hmac_drbg_context *ctx );
+
+/**
+ * \brief               HMAC_DRBG initial seeding
+ *                      Seed and setup entropy source for future reseeds.
+ *
+ * \param ctx           HMAC_DRBG context to be seeded
+ * \param md_info       MD algorithm to use for HMAC_DRBG
+ * \param f_entropy     Entropy callback (p_entropy, buffer to fill, buffer
+ *                      length)
+ * \param p_entropy     Entropy context
+ * \param custom        Personalization data (Device specific identifiers)
+ *                      (Can be NULL)
+ * \param len           Length of personalization data
+ *
+ * \note                The "security strength" as defined by NIST is set to:
+ *                      128 bits if md_alg is SHA-1,
+ *                      192 bits if md_alg is SHA-224,
+ *                      256 bits if md_alg is SHA-256 or higher.
+ *                      Note that SHA-256 is just as efficient as SHA-224.
+ *
+ * \return              0 if successful, or
+ *                      MBEDTLS_ERR_MD_BAD_INPUT_DATA, or
+ *                      MBEDTLS_ERR_MD_ALLOC_FAILED, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED.
+ */
+int mbedtls_hmac_drbg_seed( mbedtls_hmac_drbg_context *ctx,
+                    const mbedtls_md_info_t * md_info,
+                    int (*f_entropy)(void *, unsigned char *, size_t),
+                    void *p_entropy,
+                    const unsigned char *custom,
+                    size_t len );
+
+/**
+ * \brief               Initilisation of simpified HMAC_DRBG (never reseeds).
+ *                      (For use with deterministic ECDSA.)
+ *
+ * \param ctx           HMAC_DRBG context to be initialised
+ * \param md_info       MD algorithm to use for HMAC_DRBG
+ * \param data          Concatenation of entropy string and additional data
+ * \param data_len      Length of data in bytes
+ *
+ * \return              0 if successful, or
+ *                      MBEDTLS_ERR_MD_BAD_INPUT_DATA, or
+ *                      MBEDTLS_ERR_MD_ALLOC_FAILED.
+ */
+int mbedtls_hmac_drbg_seed_buf( mbedtls_hmac_drbg_context *ctx,
+                        const mbedtls_md_info_t * md_info,
+                        const unsigned char *data, size_t data_len );
+
+/**
+ * \brief               Enable / disable prediction resistance (Default: Off)
+ *
+ * Note: If enabled, entropy is used for ctx->entropy_len before each call!
+ *       Only use this if you have ample supply of good entropy!
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param resistance    MBEDTLS_HMAC_DRBG_PR_ON or MBEDTLS_HMAC_DRBG_PR_OFF
+ */
+void mbedtls_hmac_drbg_set_prediction_resistance( mbedtls_hmac_drbg_context *ctx,
+                                          int resistance );
+
+/**
+ * \brief               Set the amount of entropy grabbed on each reseed
+ *                      (Default: given by the security strength, which
+ *                      depends on the hash used, see \c mbedtls_hmac_drbg_init() )
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param len           Amount of entropy to grab, in bytes
+ */
+void mbedtls_hmac_drbg_set_entropy_len( mbedtls_hmac_drbg_context *ctx,
+                                size_t len );
+
+/**
+ * \brief               Set the reseed interval
+ *                      (Default: MBEDTLS_HMAC_DRBG_RESEED_INTERVAL)
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param interval      Reseed interval
+ */
+void mbedtls_hmac_drbg_set_reseed_interval( mbedtls_hmac_drbg_context *ctx,
+                                    int interval );
+
+/**
+ * \brief               HMAC_DRBG update state
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param additional    Additional data to update state with, or NULL
+ * \param add_len       Length of additional data, or 0
+ *
+ * \note                Additional data is optional, pass NULL and 0 as second
+ *                      third argument if no additional data is being used.
+ */
+void mbedtls_hmac_drbg_update( mbedtls_hmac_drbg_context *ctx,
+                       const unsigned char *additional, size_t add_len );
+
+/**
+ * \brief               HMAC_DRBG reseeding (extracts data from entropy source)
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param additional    Additional data to add to state (Can be NULL)
+ * \param len           Length of additional data
+ *
+ * \return              0 if successful, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
+ */
+int mbedtls_hmac_drbg_reseed( mbedtls_hmac_drbg_context *ctx,
+                      const unsigned char *additional, size_t len );
+
+/**
+ * \brief               HMAC_DRBG generate random with additional update input
+ *
+ * Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
+ *
+ * \param p_rng         HMAC_DRBG context
+ * \param output        Buffer to fill
+ * \param output_len    Length of the buffer
+ * \param additional    Additional data to update with (can be NULL)
+ * \param add_len       Length of additional data (can be 0)
+ *
+ * \return              0 if successful, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG.
+ */
+int mbedtls_hmac_drbg_random_with_add( void *p_rng,
+                               unsigned char *output, size_t output_len,
+                               const unsigned char *additional,
+                               size_t add_len );
+
+/**
+ * \brief               HMAC_DRBG generate random
+ *
+ * Note: Automatically reseeds if reseed_counter is reached or PR is enabled.
+ *
+ * \param p_rng         HMAC_DRBG context
+ * \param output        Buffer to fill
+ * \param out_len       Length of the buffer
+ *
+ * \return              0 if successful, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_REQUEST_TOO_BIG
+ */
+int mbedtls_hmac_drbg_random( void *p_rng, unsigned char *output, size_t out_len );
+
+/**
+ * \brief               Free an HMAC_DRBG context
+ *
+ * \param ctx           HMAC_DRBG context to free.
+ */
+void mbedtls_hmac_drbg_free( mbedtls_hmac_drbg_context *ctx );
+
+#if defined(MBEDTLS_FS_IO)
+/**
+ * \brief               Write a seed file
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param path          Name of the file
+ *
+ * \return              0 if successful, 1 on file error, or
+ *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED
+ */
+int mbedtls_hmac_drbg_write_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
+
+/**
+ * \brief               Read and update a seed file. Seed is added to this
+ *                      instance
+ *
+ * \param ctx           HMAC_DRBG context
+ * \param path          Name of the file
+ *
+ * \return              0 if successful, 1 on file error,
+ *                      MBEDTLS_ERR_HMAC_DRBG_ENTROPY_SOURCE_FAILED or
+ *                      MBEDTLS_ERR_HMAC_DRBG_INPUT_TOO_BIG
+ */
+int mbedtls_hmac_drbg_update_seed_file( mbedtls_hmac_drbg_context *ctx, const char *path );
+#endif /* MBEDTLS_FS_IO */
+
+
+#if defined(MBEDTLS_SELF_TEST)
+/**
+ * \brief               Checkup routine
+ *
+ * \return              0 if successful, or 1 if the test failed
+ */
+int mbedtls_hmac_drbg_self_test( int verbose );
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* hmac_drbg.h */