On Storing Private Keys "In the Cloud"
Many future applications, such as distributed social networks, will rely on public-key cryptography, and users will want to access them from many locations. Currently, there is no way to store private keys "In the cloud" without placing complete faith in a centralised operator. The authors propose a protocol that can be used to share secrets such as private keys among several key recovery agents, using a weak password, in a way that prevents insiders from recovering either the private key or the password without significant collusion. This protocol will enable the safe storage of private keys online, which will facilitate the advent of secure, decentralized, globally-accessible systems.