Editing Information theory (section)

===Pseudorandom number generation===
{{Unreferenced section|date=April 2024}}
[[Pseudorandom number generator]]s are widely available in computer language libraries and application programs. They are, almost universally, unsuited to cryptographic use as they do not evade the deterministic nature of modern computer equipment and software. A class of improved random number generators is termed [[cryptographically secure pseudorandom number generator]]s, but even they require [[random seed]]s external to the software to work as intended. These can be obtained via [[Extractor (mathematics)|extractors]], if done carefully. The measure of sufficient randomness in extractors is [[min-entropy]], a value related to Shannon entropy through [[Rényi entropy]]; Rényi entropy is also used in evaluating randomness in cryptographic systems. Although related, the distinctions among these measures mean that a random variable with high Shannon entropy is not necessarily satisfactory for use in an extractor and so for cryptography uses.