Modern encryption, namely the RSA algorithm, employs the strategy that it wraps up your messages in a big ball of numeric yarn and it would take computers till the end of time to unwind that yarn. That is, today’s computers have to unwrap that yarn one thread at a time, but quantum computers can unwrap many threads at a time. If the first commercial 16 qbit computer is going to be released, think of the kind of quantum computing power the NSA must have.