gnunet

#include <stdio.h>
#include <gnunet/gnunet_util_lib.h>

int main(int argc, char *argv[]) {
    struct GNUNET_CRYPTO_RNG_Handle *handle;
    unsigned char buffer[10];

    GNUNET_log_setup("example-gnunet", "WARNING", NULL);

    GNUNET_CRYPTO_rng_init();
    handle = GNUNET_CRYPTO_rng_create();
    GNUNET_CRYPTO_random_block(handle, buffer, sizeof(buffer));

    printf("Random bytes: ");
    for (unsigned int i = 0; i < sizeof(buffer); i++) {
        printf("%02X ", buffer[i]);
    }
    printf("\n");

    GNUNET_CRYPTO_rng_destroy(handle);
    GNUNET_CRYPTO_rng_done();

    return 0;
}

Explanation:

1. Include necessary headers: #include <stdio.h> for standard input and output, and #include <gnunet/gnunet_util_lib.h> for the GNUnet utility library.

2. Define the main function with command line arguments argc and argv.

3. Declare a variable handle of type struct GNUNET_CRYPTO_RNG_Handle* to hold the random number generator handle.

4. Declare an array buffer of unsigned characters to store the generated random bytes.

5. Set up logging for GNUnet with GNUNET_log_setup function, specifying the application name, log level ("WARNING" in this case), and additional options (NULL in this case).

6. Initialize the GNUnet crypto library with GNUNET_CRYPTO_rng_init.

7. Create a random number generator handle using GNUNET_CRYPTO_rng_create.

8. Generate random bytes using GNUNET_CRYPTO_random_block function, passing the handle, buffer, and the size of the buffer.

9. Print the generated random bytes in hexadecimal format using a loop.

10. Clean up by destroying the random number generator handle with GNUNET_CRYPTO_rng_destroy.

11. Finalize the GNUnet crypto library with GNUNET_CRYPTO_rng_done.

12. Return 0 to indicate successful execution of the program.