Ive been following zerocoin very closely since its first mention. They have just released another white paper and Id like to propose that the devs have a look at these ideas if they havnt yet. There are some extremely secure features:http://ifca.ai/fc14/bitcoin/papers/bitcoin14_submission_12.pdfAnyone else heard of this coin?
I heard it at the NXT thread. They are working at it to implement some features of Zerocoin into NXT.