Pseudo Random number generation in C using libsodium

user_11971155 0
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I am trying to create a sequence of integers which is the same everytime as the generator is seeded however I am struggling to get it working. Right now the sequence is never the same.

#include "sodium.h"
#include <stdio.h>
#include <string.h>
#include <stdlib.h>

main()
{
    if (sodium_init() == -1)
    {
        return 1;
    }

    unsigned int myInts[128];
    char seed[randombytes_SEEDBYTES] = "a seeeeeed";
    printf("%s", seed);

    randombytes_buf_deterministic(myInts, 128, seed);

    for (int i = 0; i < 128; i++)
    {
        printf("\n(%u)", myInts[i]);
    }
}
libsodium c
1 Answers

The problem is, that here

randombytes_buf_deterministic(myInts, 128, seed);

you generate 128 bytes of pseudorandom-data, but your buffer

unsigned int myInts[128];

is sizeof(int)*128 bytes big. So you have to generate enough data with

randombytes_buf_deterministic(myInts, sizeof(myInts), seed);

to fill the whole buffer with deterministic values. Then it should give the output you expect.

user_56367750
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