Classical- versus Quantum Computing. Theoretically factorization is efficient on quantum computers using Shor’s algorithm (Shor 1997). This algorithm has a non-classical quantum subroutine, embedded in a deterministic classical program. Collections of quantum bits can be modeled in terms of complex higher dimensional vector-spaces, that, in principle, allow us to analyze an exponential number \(2^n\) of correlations between collections of n objects. Currently it is not clear whether larger quantum computers will be stable enough to facilitate practical applications, but that the world at quantum level has relevant computational possibilities can not be doubted anymore, e.g., quantum random generators are available as a commercial product (see Wikipedia entry on Hardware random number generator  [OIR]).  As soon as viable quantum computers become available almost all of the current encryption techniques become useless, although they can be replaced by quantum versions of encryption techniques (see the entry on Quantum Computiong).