Which term is used for a device that generates random numbers?

• A. Cipher Generator
• B. Pseudorandom Generator
• C. Random Number Generator (RNG)
• D. Entropy Source

Answer: (C)

The main idea is to recognize the standard term for a device that outputs random numbers. A Random Number Generator, or RNG, is the name used for any device or software that produces a sequence of numbers whose behavior has the properties of randomness for practical purposes. This encompasses both hardware-based generators that rely on physical processes to generate true randomness and software-based generators that produce numbers algorithmically.

Understanding the nuance helps in gambling contexts: a true RNG (often hardware) relies on unpredictable physical phenomena, while a pseudorandom generator uses an algorithm and a seed to produce a long sequence that appears random but is deterministic if the seed is known. Casinos and testers care about randomness quality and unpredictability, and RNG is the umbrella term that covers the mechanisms used to generate those numbers.

An entropy source, on the other hand, provides raw randomness that can seed an RNG but does not by itself continuously produce a usable stream of random numbers. A pseudorandom generator describes the algorithmic process that produces numbers from a seed, which is not identical to a device that directly generates random numbers. A cipher generator isn't a standard term in this context.