Secure cloud computing based on threshold homomorphic encryption

We analyze the possibility of implementation of cloud computing over private data that is based on previously proposed threshold fully homomorphic cryptosystems. The main result is a protocol for securer cloud computing over private data in a model with supplementary cryptoservers. As a result, one gets a system that does not require a public key and replaces a sophisticated and costly bootstrapping by a more efficient reencryption protocol run by the cryptoservers.