!!! Overview
A [{$pagename}] ([CSPRNG] or [CPRNG]) is a [pseudorandom number generator] ([PRNG]) with properties that make it suitable for use in [cryptography].

Ideally, the generation of random numbers in [{$pagename}]s uses [entropy] obtained from a high-quality source, which might be a hardware random number generator or perhaps unpredictable system processes — though unexpected correlations have been found in several such ostensibly independent processes. 

From an information-theoretic point of view, the [entropy] that can be generated, is equal to the [entropy] provided by the system. But sometimes, in practical situations, more [random] numbers are needed than there is [entropy] available. 

Also the processes to extract randomness from a running system are slow in actual practice. In such instances, a [{$pagename}] can sometimes be used. A [{$pagename}] can "stretch" the available [entropy] over more [bits].

In [Cryptography] discussions we typically make a [Computational Hardness Assumption].

!! More Information
There might be more information for this subject on one of the following:
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* [#1] - [Cryptographically_secure_pseudorandom_number_generator|Wikipedia:Cryptographically_secure_pseudorandom_number_generator|target='_blank'] - based on data observed:2015-05-18