Towards Practical Homomorphic Encryption in Cloud Computing

Secure computing in clouds faces many challenges related to data confidentiality and integrity. Classical security models focus on securing data from outside attacks, e.g. from other cloud users. Yet, breach of data confidentiality by the cloud provider has received far less attention. In previous work, we presented a protocol to delegate computations into clouds, providing security against other cloud users and cloud providers through encrypted data. The protocol is based on homomorphic properties of encryption algorithms. However,that protocol was only practical in certain circumstances. In the present paper we introduce some practical extensions to our algorithm to improve its efficiency. Additionally we extend the algorithm to support multiparty computation while preserving its homomorphic properties. We then show how these optimization blocks can be used for applying the scheme to efficient face recognition using Eigenface recognition algorithm.