My colleague and I are writing a software named hin2n-ios, which is an implementation of n2n (a peer to peer VPN software) on iOS platform. So it is inevitable to call or use the code of n2n.

the n2n software is under GPLv3. But I don't want to make our software ( main project at least ) under GPLv3 or open-source by some reasons. Is it possible ?

By the way, the hin2n-ios is almost developed.