Efficient Distributed Tag-Based Encryption and its Application to Group Signatures with Efficient Distributed Traceability, by Essam Ghadafi
In this work, we first formalize the notion of dynamic group signatures with distributed traceability, where the capability to trace signatures is distributed among $n$ managers without requiring any interaction. This ensures that only the participation of all tracing managers permits tracing a signature, which reduces the trust placed in a single tracing manager. The threshold variant follows easily from our definitions and constructions. Our model offers strong security requirements.
Our second contribution is a generic construction for the notion which has a concurrent join protocol, meets strong security requirements, and offers efficient traceability, i.e.\\ without requiring tracing managers to produce expensive zero-knowledge proofs for tracing correctness. To dispense with the expensive zero-knowledge proofs required in the tracing, we deploy a distributed tag-based encryption with public verifiability.
Finally, we provide some concrete instantiations, which, to the best of our knowledge, are the first efficient provably secure realizations in the standard model simultaneously offering all the aforementioned properties. To realize our constructions efficiently, we construct an efficient distributed (and threshold) tag-based encryption scheme that works in the efficient Type-III asymmetric bilinear groups. Our distributed tag-based encryption scheme yields short ciphertexts (only 1280 bits at 128-bit security), and is secure under an existing variant of the standard decisional linear assumption.
Our tag-based encryption scheme is of independent interest and is useful for many applications beyond the scope of this paper. As a special case of our distributed tag-based encryption scheme, we get an efficient tag-based encryption scheme in Type-III asymmetric bilinear groups that is secure in the standard model.
Post-Doc, Commissariat à l\'Energie Atomique (French DoE), Paris area, France
Following recent advances in high throughput sequencing, it can be expected that, in the near future, more and more individuals will have their whole genome extracted, stored and analyzed in a routine fashion. Although this perspective is full of promises in terms of personalized preventive and curative medicine as well as medical research, it should also be acknowledged that the genome of an individual is in essence extremely sensitive data from (at least) a privacy standpoint. Thus, for such personalized medicine-oriented platforms to reliably exist, it is necessary to develop specific counter-measures providing intrinsic protection of the genomic data when manipulated by an IT infrastructure.
In this context, a very promising approach is grounded in homomorphic encryption as a means of computing directly over encrypted data.
The purpose of the present postdoctoral offer is thus to investigate the practical relevance of using homomorphic encryption techniques for privacy-preserving genetic data processing. The main use case will consist in performing requests on a database of genomes represented by their variants. Several scenarios will be investigated in particular with respect to the privacy of the request itself on top of the privacy of the genetic data. In this various scenarios, the candidate is expected to identify the most suitable homomorphic encryption techniques ranging from additive-only (e.g. suitable for private requests on unencrypted data) and multiplicative-only (e.g. suitable for disjunctive public requests on encrypted genetic data) homomorphic encryption systems to the use of the more recent (and more costly) fully homomorphic encryption techniques. The candidate will also be expected to build prototypes for one or more of the above scenarios in order to experimentally demonstrate the practical viability of the solutions, in particular with respect to performances.
IACR 2014 Election: Vote now!
IACR 2014 Election
The 2014 election is being held to fill three of nine IACR Director positions.
The 2014 Election for Directors of the IACR Board is now open. Eligible IACR members may vote now through November 15th using the Helios cryptographically-verifiable election system. You may vote as often as you wish, but only your last vote will be counted.
Eligible members of the IACR (generally people who attended an IACR conference or workshop in 2013) should have received voting credentials from email@example.com, sent to their email address of record with the IACR. Questions about this election may be sent to firstname.lastname@example.org.
More information about the candidates can be found at the IACR elections page.
- Bart Preneel (Chair)
- Michel Abdalla (Returning Officer)
- Anna Lysyanskaya
PhD Student, RMIT University, Melbourne, Australia
Recently, there has been increasing interest in the paradigm of data mining-as-a-service, where a company lacking of expertise of computation resources outsources its mining needs to the cloud. However, privacy concerns have become a major barrier to the widespread growth of data mining-as-a-service.
We offer one PhD scholarship to support a PhD student to work on a project which aims to explore practical privacy-preserving solutions for cloud data mining-as-a-service. The candidate is expected to submit a PhD thesis based on the research.
Candidates should have a Master degree in Computer Science, Knowledge of cryptographic protocols, data mining algorithms and cloud computing architecture. Publications in database security and privacy will be regarded as an additional merit.
Send your CV and publication record to xun.yi (at) rmit.edu.au.