Physical Cryptography

We recall a series of physical cryptography solutions and provide the reader with relevant security analyses. We mostly turn our attention to describing attack scenarios against schemes solving Yao\u27s millionaires\u27 problem, protocols for comparing information without revealing it and public key cryptosystems based on physical properties of systems

Private Permutations in Card-based Cryptography

電気通信大学202

GMPLS Label Space Minimization through Hypergraph Layouts

International audienceAll-Optical Label Switching (AOLS) is a new technology that performs packet forwarding without any optical-electrical-optical conversions. In this paper, we study the problem of routing a set of requests in AOLS networks using GMPLS technology, with the aim of minimizing the number of labels required to ensure the forwarding. We first formalize the problem by associating to each routing strategy a logical hypergraph, called a hypergraph layout, whose hyperarcs are dipaths of the physical graph, called tunnels in GMPLS terminology. We define a cost function for the hypergraph layout, depending on its total length plus its total hop count. Minimizing the cost of the design of an AOLS network can then be expressed as finding a minimum cost hypergraph layout. We prove hardness results for the problem, namely for general directed networks we prove that it is NP-hard to find a C log n-approximation, where C is a positive constant and n is the number of nodes of the network. For symmetric directed networks, we prove that the problem is APX-hard. These hardness results hold even if the traffic instance is a partial broadcast. On the other hand, we provide approximation algorithms, in particular an O(log n)-approximation for symmetric directed networks. Finally, we focus on the case where the physical network is a directed path, providing a polynomial-time dynamic programming algorithm for a fixed number k of sources running in O(n^{k+2}) time

Application of Analogical Reasoning for Use in Visual Knowledge Extraction

There is a continual push to make Artificial Intelligence (AI) as human-like as possible; however, this is a difficult task because of its inability to learn beyond its current comprehension. Analogical reasoning (AR) has been proposed as one method to achieve this goal. Current literature lacks a technical comparison on psychologically-inspired and natural-language-processing-produced AR algorithms with consistent metrics on multiple-choice word-based analogy problems. Assessment is based on “correctness” and “goodness” metrics. There is not a one-size-fits-all algorithm for all textual problems. As contribution in visual AR, a convolutional neural network (CNN) is integrated with the AR vector space model, Global Vectors (GloVe), in the proposed, Image Recognition Through Analogical Reasoning Algorithm (IRTARA). Given images outside of the CNN’s training data, IRTARA produces contextual information by leveraging semantic information from GloVe. IRTARA’s quality of results is measured by definition, AR, and human factors evaluation methods, which saw consistency at the extreme ends. The research shows the potential for AR to facilitate more a human-like AI through its ability to understand concepts beyond its foundational knowledge in both a textual and visual problem space

Architectural Exploration of Data Recomputation for Improving Energy Efficiency

University of Minnesota Ph.D. dissertation. July 2017. Major: Electrical/Computer Engineering. Advisor: Ulya Karpuzcu. 1 computer file (PDF); viii, 99 pages.There are two fundamental challenges for modern computer system design. The first one is accommodating the increasing demand for performance in a tight power budget. The second one is ensuring correct progress despite the increasing possibility of faults that may occur in the system. To address the first challenge, it is essential to track where the power goes. The energy consumption of data orchestration (i.e., storage, movement, communication) dominates the energy consumption of actual data production, i.e., computation. Oftentimes, recomputing data becomes more energy efficient than storing and retrieving pre-computed data by minimizing the prevalent power and performance overhead of data storage, retrieval, and communication. At the same time, recomputation can reduce the demand for communication bandwidth and shrink the memory footprint. In the first half of the dissertation, the potential of data recomputation in improving energy efficiency is quantified and a practical recomputation framework is introduced to trade computation for communication. To address the second challenge, it is needed to provide scalable checkpointing and recovery mechanisms. The traditional method to recover from a fault is to periodically checkpoint the state of the machine. Periodic checkpointing of the machine state makes rollback and restart of execution from a safe state possible upon detection of a fault. The energy overhead of checkpointing, however, as incurred by storage and communication of the machine state grows with the frequency of checkpointing. Amortizing this overhead becomes especially challenging, considering the growth of expected error rates as an artifact of contemporary technology scaling. Recomputation of data (which otherwise would be read from a checkpoint) can reduce both the frequency of checkpointing, the size of the checkpoints and thereby mitigate checkpointing overhead. In the second half, quantitative characterization of recomputation-enabled checkpointing (based on recomputation framework) is provided