Editing Quantum Random Number Generator (section)

==Use Case==
Randomness expansion is useful in the case where one already has access to a private source for true randomness, but whose use is prohibitively expensive or whose access is limited. This is not possible classically.

In a similar vein, it is only possible to extract uniform, private randomness by combining multiple weak sources together classically. Randomness amplification enables the extraction of such randomness from only a single weak source - useful in any situation where only some randomness has been provided but absolute security is required.