Random number generator (RNG)

RNG examples

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>

#include <qcrypto/qcrypto.h>
#include <qcrypto/qcrypto_error.h>

#define RNG_BYTES			32

int main(int argc, char *argv[])
{
    int ret;
    qcrypto_ctx_t *qctx = NULL;
    const char *personal_str = "Hello World!";
    uint8_t result[RNG_BYTES];
    uint8_t seed[16] = {0};
    bool quiet = false;

    /* Initialize the Qcrypto Library */
    ret = qcrypto_init(QCRYPTO_INIT_LAZY, NULL);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcryto_init() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Request drbg-ctr-128 */
    ret = qcrypto_rng_request("drbg-ctr-128", NULL, 0, &qctx);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_rng_request() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Initialize RNG arguments */
    qcrypto_rng_args_t rargs = {
        .drbg.pstr = (const uint8_t*)personal_str,
        .drbg.pstrsize = sizeof(personal_str),
    };

    /* Initialize an RNG */
    ret = qcrypto_rng_init(qctx, &rargs);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_rng_init() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Seed the RNG */
    ret = qcrypto_rng_seed(qctx, seed, sizeof(seed));
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_rng_seed() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Extracts a random value from the RNG */
    ret = qcrypto_rng_bytes(qctx, result, RNG_BYTES);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_rng_bytes() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Print the result */
    if ((argc > 1) && (strcmp(argv[1], "test") == 0)) {
        quiet = true;
    }

    if (!quiet) {
        printf("The random value generated from PRNG is: ");
        for (int i=0; i<RNG_BYTES; i++) {
            printf("%02X", result[i]);
        }
        putchar('\n');
    }

    printf("\n %s", "Success! A random value has been generated from PRNG! \n");
    goto done;

done:
    /* Release the RNG context handle */
    qcrypto_release_ctx(qctx);

    /* Uninitialize the Qcrypto Library */
    qcrypto_uninit();

    return ret;
}