It's not clear from the title but what makes the described cryptosystem special is that it is considered to remain secure even if the attacker has access to a large quantum computer.

For those interested in an approachable high-level view on post quantum crypto DJB and Tanja Lange gave a talk about it at 32C3[1].

[1] https://media.ccc.de/v/32c3-7210-pqchacks