ctr_drbg.h

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#ifndef MBEDTLS_CTR_DRBG_H
#define MBEDTLS_CTR_DRBG_H

#include "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      
#define MBEDTLS_CTR_DRBG_KEYSIZE            32      
#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
#define MBEDTLS_CTR_DRBG_ENTROPY_LEN        32      
#endif
#endif

#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

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

    void *p_entropy;            
#if defined(MBEDTLS_THREADING_C)
    mbedtls_threading_mutex_t mutex;
#endif
}
mbedtls_ctr_drbg_context;

void mbedtls_ctr_drbg_init( mbedtls_ctr_drbg_context *ctx );

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 );

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 );

void 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 );

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 */

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 */