An unconditionally hiding auditing procedure for computations over distributed data
Lucas Schabhüser, Denise Demirel, Johannes A Buchmann · 2016
In this work an unconditionally hiding auditing procedure for distributed (cloud) storage solutions is introduced. There is only one multi-party computation (MPC) scheme providing auditability which computationally protects the inputs of the computations. Building on this, we propose a computationally hiding solution that uses bilinear maps and therefore produces no additional overhead in the online phase. In addition, we introduce a second variation that is the first auditable MPC scheme for distributed storage systems providing unconditional (or information-theoretic) hidingness. We achieve this by combining bilinear maps with unconditionally hiding commitments leading to only a small overhead in the online phase. We prove our solutions secure and give arguments for practicability and efficiency. The auditing procedures presented here are an important contribution since distributed storage solutions, e.g. cloud of clouds, allow for information-theoretic confidentiality. Using our technique, they can be extended to perform auditable computations on the data stored.