TUDA, AIT, TUGRAZ, UNEW
PRISMACLOUD aims at bringing novel cryptographic concepts and methods to practical application, to improve the security and privacy of cloud based services, and make them usable for providers and users. The purpose of this deliverable is to present research results developed within PRISMACLOUD that focuses on authenticators providing long term security. In particular we show novel authenticators providing everlasting privacy that can be used within the VERIDAP tool. This tool relies on verifiable computing schemes allowing for verifiable data processing by means of performing verifiable computations on data stored in the cloud. It was described in detail in Deliverable D5.10. In Deliverable D5.11 it was shown how to extend the tool to support operations on data stored in distributed fashion, i.e. stored as secret shares. Proactive secret sharing is known to provide long-term privacy with respect to the shareholders. In this deliverable we now present authenticators that provide long-term privacy with respect to the verifiers.
Proactive secret sharing often uses commitments to ensure the integrity of the shared data after share renewal. We present research results on share renewal, that preserves information theoretic privacy.
We additionally present research results on the topic of post-quantum unforgeable authenticators. Here the long-term security focus is on the unforgeability of authenticators in particular signatures in the future against the presence of quantum adversaries.
Finally we will present our work on zero-knowledge proofs, that can be used in our TOPOCERT tool, as detailed in Deliverable D5.7. Here the sensitive information is also private with respect to verifiers in an information theoretic sense, thus achieving long-term privacy.