On-the-fly multiparty computation on the cloud via multikey fully homomorphic encryption

We propose a new notion of secure multiparty computation aided by a computationally-powerful but untrusted “cloud” server. In this notion that we call on-the-fly multiparty computation (MPC), the cloud can non-interactively perform arbitrary, dynamically chosen computations on data belonging to arbitrary sets of users chosen on-the-fly. All user’s input data and intermediate results are protected from snooping by the cloud as well as other users. This extends the standard notion of fully homomorphic encryption (FHE), where users can only enlist the cloud’s help in evaluating functions on their own encrypted data. In on-the-fly MPC, each user is involved only when initially uploading his (encrypted) data to the cloud, and in a final output decryption phase when outputs are revealed; the complexity of both is independent of the function being computed and the total number of users in the system. When users upload their data, they need not decide in advance which function wil...

• Type: Journal
• Year: 2012
• Where: STOC
• Authors: Adriana López-Alt, Eran Tromer, Vinod Vaikuntanathan
• Keywords: Algorithms, Arbitrary Sets, Generic Program, Multiparty Computation, STOC 2012