Generating RSA keys on a handheld using an untrusted server

Abstract

We show how to efficiently generate RSA keys on a low power handheld device with the help of an untrusted server. Most of the key generation work is offloaded onto the server. However, the server learns no information about the key it helped generate. We experiment with our techniques and show they result in up to a factor of 5 improvement in key generation time. The resulting RSA key looks like an RSA key for paranoids. It can be used for encryption and key exchange, but cannot be used for signatures.