Pseudorandomness

As a pseudo-random is called what appears to be random, but in reality it is predictable.

Pseudorandom in computability theory

In computability theory all this is called pseudo-randomly, which can not be distinguished from true randomness from the perspective of the viewer. The result of a coin toss, for example, generally considered to be random. The coin is already in the air, it is theoretically possible to predict the outcome based on their rotation, speed, etc.. Someone, the appropriate measuring instruments ( and computing capacity ) are not available, the throw will still randomly; the union with the coin in the air is pseudo-random for him. Generally one defined in computability theory as pseudo-randomly, which can not be predicted by means of efficient algorithms. But pseudo- randomness is still predictable ( they can efficiently produce ), but not predictable. Pseudo-random generators according to this definition of pseudo- randomness presuppose the existence of explicit hard functions.