Is extracting data the same as possessing data?, by Douglas R. Stinson and Jalaj Upadhyay
Proof-of-retrievability schemes have been a topic of considerable recent interest. In these schemes, a client gives a file M to a server with the understanding that the server will securely store M. A suitable challenge-response protocol is invoked by the client in order for the client to gain confidence that M is indeed being correctly stored by the server. The definition of proof-of-retrievability schemes is based on the notion of an extractor that can recover the file once the challenge-response protocol is executed a sufficient number of times.
In this paper, we propose a new type of scheme that we term a proof-of-data-observability scheme. Our definition tries to capture the stronger requirement that the server must have
an actual copy of M in its memory space while it executes the challenge-response protocol.
We give some examples of schemes that satisfy this new security definition. As well, we analyze the efficiency and security of the protocols we present, and we prove some necessary conditions for the existence of these kinds of protocols.
Privacy and Verifiability in Voting Systems: Methods, Developments and Trends, by Hugo Jonker and Sjouke Mauw and Jun Pang
One of the most challenging aspects in computer-supported voting is to combine the apparently conflicting requirements of privacy and verifiability. On the one hand, privacy requires that a vote cannot be traced back from the result to a voter, while on the other hand,
verifiability states that a voter can trace the effect of her vote on the result. This can be addressed using various privacy-enabling cryptographic primitives which also offer verifiability.
As more and more refined voting systems were proposed, understanding of first privacy and later verifiability in voting increased, and notions of privacy as well as notions of verifiability in voting became increasingly more refined. This has culminated in a variety of verifiable systems that use cryptographic primitives to ensure specific kinds of privacy. However, the corresponding privacy and verifiability claims are not often verified independently. When they are investigated, claims have been invalidated sufficiently often to warrant a cautious approach to them.
The multitude of notions, primitives and proposed solutions that claim to achieve both privacy and verifiability form an interesting but complex landscape. The purpose of this paper is to
survey this landscape by providing an overview of the methods, developments and current trends regarding privacy and verifiability in voting systems.
Accelerating Fully Homomorphic Encryption over the Integers with Super-size Hardware Multiplier and Modular Reduction, by Xiaolin Cao, Ciara Moore, Maire O\'Neill, Elizabeth O\'Sullivan and Neil Hanle
A fully homomorphic encryption (FHE) scheme is envisioned as being a key cryptographic tool in building a secure and reliable cloud computing environment, as it allows arbitrarily evaluation of a ciphertext without revealing the plaintext. However, existing FHE implementations remain impractical due to their very high time and resource costs. Of the proposed schemes that can perform FHE to date, a scheme known as FHE over the integers has the ad-vantage of comparatively simpler theory, as well as the employment of a much shorter public key making its implementation somewhat more practical than other competing schemes.
To the author\'s knowledge, this paper presents the first hardware implemen-tations of encryption primitives for FHE over the integers using FPGA technol-ogy. First of all, a super-size hardware multiplier architecture utilising the Inte-ger-FFT multiplication algorithm is proposed, and a super-size hardware Barrett modular reduction module is designed incorporating the proposed multiplier. Next, two encryption primitives that are used in two schemes of FHE over the integers are designed employing the proposed super-size multiplier and modular reduction modules. Finally, the proposed designs are implemented and verified on the Xilinx Virtex-7 FPGA platform. Experimental results show that the speed improvement factors of up to 44.72 and 54.42 are available for the two FHE encryption schemes implemented in FPGA when compared to the corresponding software implementations. Meanwhile, the performance analysis shows that further improvement is speed of these FHE encryption primitives may still be possible.
Cryptographic Researcher, Security Innovation, Wilmington, MA, USA
We’re planning to make a hire at Security Innovation to support our NTRU crypto research program, including providing support for the codebase of our NTRU implementations once we make it available under GPL.
Responsibilities will include:
· Work on NTRU crypto research, including efficient signature schemes
· Helping to better understand lattice reduction algorithms, potentially including:
o A complete or partial reimplementation of algorithms developed by Nguyen and Chen to properly understand their claims
o Research into use of the structure of NTRU / ideal lattices to obtain improvements over generic lattice reduction algorithms
o Exploring the relationship between expected-shortest and actual-shortest vector in a lattice and how it affects reduction times
· Support cryptographic queries that come in to NTRU as a result of the GPL move, including participating in discussions on forums such as crypto.stackexchange and others
· Support the codebase of the GPL implementation of NTRU, including:
o General optimizations for the C implementation on 32- and 64-bit processors such as including multiple coefficients in a single word
o Architecture-specific optimizations such as exploring what advantage can be taken of SIMD, etc
o Potentially writing and/or managing a Java implementation
· Support standardization activity
o In particular, manage the passing of one or more NTRU-related TLS ciphersuite drafts through IETF.
Associate Professor, School of Mathematical and Geospatial Sciences, RMIT University, Melbourne, Australia
Associate Professor - Mathematical Science
Full-time, Continuing (i.e., permanent) position
Annual Salary: $121,048 to $133,357 + 17% superannuation
Information Security forms one of the research strengths of the School. The Master of Applied Science in Information Security and Assurance is one of the programs in the school with more than 50 coursework students.
Please see the following link for further information about the research group
and the following for further information about Master\\\'s program in Information Security and Assurance
Situated within the College of Science, Engineering and Health, the School of Mathematical and Geospatial Sciences draws together disciplines involving the collection of data, the analysis of data, data security, and the understanding and optimisation of systems through modelling and visualisation. The School has more than 60 academic staff and over 70 postgraduate research students.
Reporting to the Head of School, the Associate Professor - Mathematical Science will be expected to be an active researcher. This will include supervising research students; undertaking and publishing high quality research, and applying for research grants.
Recomputing with Permuted Operands: A Concurrent Error Detection Approach, by Xiaofei Guo and Ramesh Karri
Naturally occurring and maliciously injected faults reduce the reliability of cryptographic hardware and may leak confidential information. We develop a concurrent error detection (CED) technique called Recomputing with Permuted Operands (REPO). We show that it is cost effective in Advanced Encryption Standard (AES) and a secure hash
function Grøstl. We provide experimental results and formal proofs to show that REPO detects all single-bit and single-byte faults. Experimental results show that REPO achieves close to 100% fault coverage for multiple byte faults. The hardware and throughput overheads are compared with those of previously reported CED techinques on two Xilinx Virtex FPGAs. The hardware overhead is 12.4-27.3%, and the throughput is 1.2-23Gbps, depending on the AES architecture, FPGA family, and detection latency. The performance overhead ranges from 10% to 100% depending on the security
level. Moreover, the proposed technique can be integrated into various block cipher modes of operation. We also discuss the limitation of REPO and its potential vulnerabilities.
Modelling Time, or A Step Towards Reduction-based Security Proofs for OTP and Kerberos, by Jörg Schwenk
The notion of time plays an important role in many practically deployed cryptographic protocols, ranging from One-Time-Password (OTP) tokens to the Kerberos protocol. However, time is difficult to model in a Turing machine environment.
We propose the first such model, where time is modelled as a global counter T . We argue that this model closely matches several implementations of time in computer environments. The usefulness of the model is shown by giving complexity-theoretic security proofs for OTP protocols, HMQV-like one-round AKE protocols, and a variant of the basic Kerberos building block.
Revocable quantum timed-release encryption, by Dominique Unruh
Timed-release encryption is a kind of encryption scheme that a
recipient can decrypt only after a specified amount of time T
(assuming that we have a moderately precise estimate of his computing
power). A revocable timed-release encryption is one where,
before the time T is over, the sender can \"give back\" the
timed-release encryption, provably loosing all access to the data. We
show that revocable timed-release encryption without trusted parties
is possible using quantum cryptography (while trivially impossible
Along the way, we develop two proof techniques in the quantum random
oracle model that we believe may have applications also for other
Finally, we also develop another new primitive, unknown recipient
encryption, which allows us to send a message to an
unknown/unspecified recipient over an insecure network in such a way
that at most one recipient will get the message.