Recently, the following article about a speech in November 2014 by Paul Rosenberg was brought to our attention.
Here is that article:
In it, Paul says, among other things, "SilentVault is a completely private network that lets you send and receive bitcoin and litecoin completely off the blockchain, while maintaing that ability to reconcile back to it later. Bitcoin transactions are ‘silenced’ within private servers with no public-facing IPs."
Recently, Paul joined the team at Digital Cash Alliance as an adviser. You can find more about the work of the Alliance by visiting their site.