/* BEGIN_HEADER */

/* Test random generation as a whole. */

#include "mbedtls/ctr_drbg.h"
#include "mbedtls/entropy.h"
#include "mbedtls/hmac_drbg.h"
#include "psa/crypto.h"

/* How many bytes to generate in each test case for repeated generation.
 * This must be high enough that the probability of generating the same
 * output twice is infinitesimal, but low enough that random generators
 * are willing to deliver that much. */
#define OUTPUT_SIZE 32

/* END_HEADER */

/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_C:MBEDTLS_CTR_DRBG_C */
void random_twice_with_ctr_drbg( )
{
    mbedtls_entropy_context entropy;
    mbedtls_ctr_drbg_context drbg;
    unsigned char output1[OUTPUT_SIZE];
    unsigned char output2[OUTPUT_SIZE];

    /* First round */
    mbedtls_entropy_init( &entropy );
    mbedtls_ctr_drbg_init( &drbg );
    TEST_EQUAL( 0, mbedtls_ctr_drbg_seed( &drbg,
                                          mbedtls_entropy_func, &entropy,
                                          NULL, 0 ) );
    TEST_EQUAL( 0, mbedtls_ctr_drbg_random( &drbg,
                                            output1, sizeof( output1 ) ) );
    mbedtls_ctr_drbg_free( &drbg );
    mbedtls_entropy_free( &entropy );

    /* Second round */
    mbedtls_entropy_init( &entropy );
    mbedtls_ctr_drbg_init( &drbg );
    TEST_EQUAL( 0, mbedtls_ctr_drbg_seed( &drbg,
                                          mbedtls_entropy_func, &entropy,
                                          NULL, 0 ) );
    TEST_EQUAL( 0, mbedtls_ctr_drbg_random( &drbg,
                                            output2, sizeof( output2 ) ) );
    mbedtls_ctr_drbg_free( &drbg );
    mbedtls_entropy_free( &entropy );

    /* The two rounds must generate different random data. */
    TEST_ASSERT( memcmp( output1, output2, OUTPUT_SIZE ) != 0 );

exit:
    mbedtls_ctr_drbg_free( &drbg );
    mbedtls_entropy_free( &entropy );
}
/* END_CASE */

/* BEGIN_CASE depends_on:MBEDTLS_ENTROPY_C:MBEDTLS_HMAC_DRBG_C */
void random_twice_with_hmac_drbg( int md_type )
{
    mbedtls_entropy_context entropy;
    mbedtls_hmac_drbg_context drbg;
    unsigned char output1[OUTPUT_SIZE];
    unsigned char output2[OUTPUT_SIZE];
    const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type( md_type );

    /* First round */
    mbedtls_entropy_init( &entropy );
    mbedtls_hmac_drbg_init( &drbg );
    TEST_EQUAL( 0, mbedtls_hmac_drbg_seed( &drbg, md_info,
                                           mbedtls_entropy_func, &entropy,
                                           NULL, 0 ) );
    TEST_EQUAL( 0, mbedtls_hmac_drbg_random( &drbg,
                                             output1, sizeof( output1 ) ) );
    mbedtls_hmac_drbg_free( &drbg );
    mbedtls_entropy_free( &entropy );

    /* Second round */
    mbedtls_entropy_init( &entropy );
    mbedtls_hmac_drbg_init( &drbg );
    TEST_EQUAL( 0, mbedtls_hmac_drbg_seed( &drbg, md_info,
                                           mbedtls_entropy_func, &entropy,
                                           NULL, 0 ) );
    TEST_EQUAL( 0, mbedtls_hmac_drbg_random( &drbg,
                                             output2, sizeof( output2 ) ) );
    mbedtls_hmac_drbg_free( &drbg );
    mbedtls_entropy_free( &entropy );

    /* The two rounds must generate different random data. */
    TEST_ASSERT( memcmp( output1, output2, OUTPUT_SIZE ) != 0 );

exit:
    mbedtls_hmac_drbg_free( &drbg );
    mbedtls_entropy_free( &entropy );
}
/* END_CASE */

/* BEGIN_CASE depends_on:MBEDTLS_PSA_CRYPTO_C:!MBEDTLS_PSA_CRYPTO_EXTERNAL_RNG */
void random_twice_with_psa_from_psa( )
{
    unsigned char output1[OUTPUT_SIZE];
    unsigned char output2[OUTPUT_SIZE];

    /* First round */
    PSA_ASSERT( psa_crypto_init( ) );
    PSA_ASSERT( psa_generate_random( output1, sizeof( output1 ) ) );
    PSA_DONE( );

    /* Second round */
    PSA_ASSERT( psa_crypto_init( ) );
    PSA_ASSERT( psa_generate_random( output2, sizeof( output2 ) ) );
    PSA_DONE( );

    /* The two rounds must generate different random data. */
    TEST_ASSERT( memcmp( output1, output2, OUTPUT_SIZE ) != 0 );

exit:
    PSA_DONE( );
}
/* END_CASE */