As I said in another thread:
Warning : their presentation is deceiving :
they replaced zerocash by zerocoin in the publications papers from zerocash team:
Proof:
the counterfeited one :

http://zerocoin.org/media/pdf/ZerocoinOakland.pdf

to be compared to the original one:
https://cs.jhu.edu/~cgarman/files/ZerocashOakland14.pdf