This has been a subject that caught my interest recently. For those that don't know a lot about SMPC, this library can be used to implement distributed cryptographic applications [1].<p>In other words, a group of peers that don't trust each other with a key can perform RSA in a distributed matter that is Byzantine Fault Tolerant (BFT). Specifically, all parties can generate a distributed key pair and then decrypt a message without specific knowledge of the private key. A fixed number of attackers (usually less than one third of the total number of participating clients) can behave in an arbitrary manner during the process without affecting the ability of the trustworthy peers to correctly decrypt the message.<p>There are of course performance issues and caveats involved, but fascinating stuff.<p>1. <a href="http://viff.dk/doc/applications.html#distributed-rsa" rel="nofollow">http://viff.dk/doc/applications.html#distributed-rsa</a>