Yeah, it's impossible to hide backdoors in open source projects, someone will find it out. There were rumors about a possible backdoor in Zcash, FUD. Privacy-centric coins use different cryptographic techniques to achieve anonymity/privacy and I guess Zcash's, zk-SNARKs protocol is the most complicated. A government agency launching their own privacy coin to catch criminals is a possibility, assuming if they used some sort of new or highly complicated privacy protocol to hide a backdoor, it wouldn't be possible to immediately identify it, it's less likely to happen than governments establishing a marketplace to trap criminals. Last year, the FBI, DEA, and the the National Dutch Police shut down two of the largest Dark Web markets, AlphaBay and Hansa. Before shutting down, the Dutch Police operated Hansa for about a month without the buyers/sellers realizing it.
It is not as if these guys are not trying. We saw what happened in Bitcoin XT. I also know that these agencies are hosting their own exit nodes on Tor, so it is being done. I can see a scenario in the future where one of these agencies might come forward with information or they get exposed on WikiLeaks again for running a "Honey trap" alt coin.
"Vault 7" should have been an eye-opener for many people, on how equipped these agencies are. Be careful out there.
Stop using Crypto currencies for illegal things. ^grrrrrr^
