ctr_drbg.h

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/*
 *  Copyright The Mbed TLS Contributors
 *  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.
 */

#ifndef MBEDTLS_CTR_DRBG_H
#define MBEDTLS_CTR_DRBG_H
#include "mbedtls/private_access.h"

#include "mbedtls/build_info.h"

#include "mbedtls/aes.h"

#if defined(MBEDTLS_THREADING_C)
#include "mbedtls/threading.h"
#endif

#define MBEDTLS_ERR_CTR_DRBG_ENTROPY_SOURCE_FAILED        -0x0034

#define MBEDTLS_ERR_CTR_DRBG_REQUEST_TOO_BIG              -0x0036

#define MBEDTLS_ERR_CTR_DRBG_INPUT_TOO_BIG                -0x0038

#define MBEDTLS_ERR_CTR_DRBG_FILE_IO_ERROR                -0x003A

#define MBEDTLS_CTR_DRBG_BLOCKSIZE          16 
#if defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)
#define MBEDTLS_CTR_DRBG_KEYSIZE            16

#else
#define MBEDTLS_CTR_DRBG_KEYSIZE            32

#endif

#define MBEDTLS_CTR_DRBG_KEYBITS            ( MBEDTLS_CTR_DRBG_KEYSIZE * 8 ) 
#define MBEDTLS_CTR_DRBG_SEEDLEN            ( MBEDTLS_CTR_DRBG_KEYSIZE + MBEDTLS_CTR_DRBG_BLOCKSIZE ) 
#if !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN)
#if defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256)

#define MBEDTLS_CTR_DRBG_ENTROPY_LEN        48

#else /* defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256) */

#if !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY)

#endif /* !defined(MBEDTLS_CTR_DRBG_USE_128_BIT_KEY) */
#define MBEDTLS_CTR_DRBG_ENTROPY_LEN        32
#endif /* defined(MBEDTLS_SHA512_C) && !defined(MBEDTLS_ENTROPY_FORCE_SHA256) */
#endif /* !defined(MBEDTLS_CTR_DRBG_ENTROPY_LEN) */

#if !defined(MBEDTLS_CTR_DRBG_RESEED_INTERVAL)
#define MBEDTLS_CTR_DRBG_RESEED_INTERVAL    10000

#endif

#if !defined(MBEDTLS_CTR_DRBG_MAX_INPUT)
#define MBEDTLS_CTR_DRBG_MAX_INPUT          256

#endif

#if !defined(MBEDTLS_CTR_DRBG_MAX_REQUEST)
#define MBEDTLS_CTR_DRBG_MAX_REQUEST        1024

#endif

#if !defined(MBEDTLS_CTR_DRBG_MAX_SEED_INPUT)
#define MBEDTLS_CTR_DRBG_MAX_SEED_INPUT     384

#endif

/* \} name SECTION: Module settings */

#define MBEDTLS_CTR_DRBG_PR_OFF             0

#define MBEDTLS_CTR_DRBG_PR_ON              1

#ifdef __cplusplus
extern "C" {
#endif

#if MBEDTLS_CTR_DRBG_ENTROPY_LEN >= MBEDTLS_CTR_DRBG_KEYSIZE * 3 / 2

#define MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN 0
#else

#define MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN ( MBEDTLS_CTR_DRBG_ENTROPY_LEN + 1 ) / 2
#endif

typedef struct mbedtls_ctr_drbg_context
{
    unsigned char MBEDTLS_PRIVATE(counter)[16];  
    int MBEDTLS_PRIVATE(reseed_counter);         
    int MBEDTLS_PRIVATE(prediction_resistance);  
    size_t MBEDTLS_PRIVATE(entropy_len);         
    int MBEDTLS_PRIVATE(reseed_interval);        
    mbedtls_aes_context MBEDTLS_PRIVATE(aes_ctx);        
    /*
     * Callbacks (Entropy)
     */
    int (*MBEDTLS_PRIVATE(f_entropy))(void *, unsigned char *, size_t);
    void *MBEDTLS_PRIVATE(p_entropy);            
#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;

void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx );

#if MBEDTLS_CTR_DRBG_ENTROPY_NONCE_LEN == 0

#else

#endif
#if defined(MBEDTLS_THREADING_C)

#endif /* MBEDTLS_THREADING_C */

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 );

void mbedtls_ctr_drbg_free( mbedtls_ctr_drbg_context *ctx );

void mbedtls_ctr_drbg_set_prediction_resistance( mbedtls_ctr_drbg_context *ctx,
                                         int resistance );

void mbedtls_ctr_drbg_set_entropy_len( mbedtls_ctr_drbg_context *ctx,
                               size_t len );

int mbedtls_ctr_drbg_set_nonce_len( mbedtls_ctr_drbg_context *ctx,
                                    size_t len );

void mbedtls_ctr_drbg_set_reseed_interval( mbedtls_ctr_drbg_context *ctx,
                                   int interval );

int mbedtls_ctr_drbg_reseed( mbedtls_ctr_drbg_context *ctx,
                     const unsigned char *additional, size_t len );

int mbedtls_ctr_drbg_update( mbedtls_ctr_drbg_context *ctx,
                             const unsigned char *additional,
                             size_t add_len );

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 );

#if defined(MBEDTLS_THREADING_C)

#endif /* MBEDTLS_THREADING_C */

int mbedtls_ctr_drbg_random( void *p_rng,
                     unsigned char *output, size_t output_len );

#if defined(MBEDTLS_FS_IO)

int mbedtls_ctr_drbg_write_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path );

int mbedtls_ctr_drbg_update_seed_file( mbedtls_ctr_drbg_context *ctx, const char *path );
#endif /* MBEDTLS_FS_IO */

#if defined(MBEDTLS_SELF_TEST)

int mbedtls_ctr_drbg_self_test( int verbose );

#endif /* MBEDTLS_SELF_TEST */

#ifdef __cplusplus
}
#endif

#endif /* ctr_drbg.h */