Is there any alternative for cryptography? I heard a lot about quantum cryptography, but is this the only stuff which have a chance to exist in the future? Are there any other kinds of cryptography?
I'm really trying to guess what you mean by this question. However, I'll try to answer. I think that you are wondering what other methods could cryptography use. Like quantum cryptography uses quantum mechanics.
A few days ago, Laszlo Kish showed another way to send information - based on thermodynamic laws.
You can read more here.
Cryptography is already an alternative, namely to "physical security systems":
Such things have been done since the invention of writing, a good 5000 years ago. Cryptography just allows to do these things faster and cheaper and farther. But this means that, should cryptography fail, you could always revert to the Old Style ways known since the days of Pharaoh, and which ultimately sum up as: just throw more money at it(*).
"Quantum cryptography" means two things:
(*) Ok, ok, I admit: there was no actual money in Ancient Egypt; the economic system was based on generalized barter, and the first use of actual currency appears only during the 5th century BC. Just imagine that Pharaoh's messengers were paid in wheat and beer.