How Can I Ensure Secure and Unpredictable Random Number Generation in C ?

Ensuring Random Number Initialization in C

When initializing a pseudo-random number generator (PRNG), it's crucial to choose an effective method to avoid predictability and collisions. One common approach is to seed the PRNG with a time-based value. However, for applications running multiple times per second, this approach can prove insufficient.

To address this issue, a more robust method is to combine multiple entropy sources. Here's an implementation that leverages clock time, Unix time, and process ID:

unsigned long seed = mix(clock(), time(NULL), getpid());

where mix is a function that combines the entropy sources:

// Robert Jenkins' 96 bit Mix Function
unsigned long mix(unsigned long a, unsigned long b, unsigned long c) {
  /* Perform a series of bitwise operations to combine the entropy sources */
  return c;
}

This method provides a portable and secure way to initialize the PRNG, ensuring unpredictable random numbers even for applications that run with high frequency.

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