Optimize the encryption code. In current versions (1.0.x) the encryption with boxcryptor is a bottleneck. If you encrypt files over a fast network (1 Gbit) you only get just 10% of the possible network speed. CPU resources are not saturated.
With version 1.3 we introduced AES hardware acceleration and other speed improvements. Up to 50 MB/sec should now be possible on modern processors. Of course, we’re constantly working on improving the speed of BoxCryptor.
Kelly Trinh commented
Still too slow - on a i7-2600k it is about 35mb/sec
Oh yeah, very important feature! Encfs4win port is MUCH MUCH Faster!