I read this about another coin. "The transactions in a block are hashed in a Merkle root tree unlike Nxt which just hashed the concatenation.  The Merkle root is resistive to quantum cryptography attacks and allows for SPV based clients to be implemented."

In the future if a quantum computer is possible, will NEM have any resistance to a quantum cryptography attack?

Experimental Evidence Confirms That D-Wave Systems Quantum Computers Are Truly Quantum
http://www.businessinsider.com/d-wave-systems-2014-6