1,720,976 research outputs found
When to Barrett reduce in the inverse NTT
Full text linkWe show that lazily Barrett reducing when computing the inverse number theoretic transform (NTT) is optimal
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Benchmarking and Analysing the NIST PQC Lattice-Based Signature Schemes Standards on the ARM Cortex M7
Full text linkThis paper presents an analysis of the two lattice-based digital signature schemes, Dilithium and Falcon, which have been chosen by NIST for standardisation, on the ARM Cortex M7 using the STM32F767ZI NUCLEO-144 development board. This research is motivated by the ARM Cortex M7 device being the only processor in the Cortex-M family to offer a double precision (i.e., 64-bit) floating-point unit, making Falcon\u27s implementations, requiring 53 bits of double precision, able to fully run native floating-point operations without any emulation. When benchmarking natively, Falcon shows significant speed-ups between 6.2-8.3x in clock cycles, 6.2-11.8x in runtime, and Dilithium does not show much improvement other than those gained by the slightly faster processor. We then present profiling results of the two schemes on the ARM Cortex M7 to show their respective bottlenecks and operations where the improvements are and can be made. This demonstrates, for example, that some operations in Falcon\u27s procedures observe speed-ups by an order of magnitude. Finally, since Falcon\u27s use of floating points is so rare in cryptography, we test the native FPU instructions on 4 different STM32 development boards with the ARM Cortex M7 and also a Raspberry Pi 3 which is used in some of Falcon\u27s official benchmarking results. We find constant-time irregularities in all of these devices, which makes Falcon insecure on these devices for applications where signature generation can be timed by an attacker
Solving binary MQ with Grover\u27s algorithm
No full textThe problem of solving a system of quadratic equations in multiple variables---known as multivariate-quadratic or MQ problem---is the underlying hard problem of various cryptosystems. For efficiency reasons, a common instantiation is to consider quadratic equations over \F_2. The current state of the art in solving the \MQ problem over \F_2 for sizes commonly used in cryptosystems is enumeration, which runs in time for a system of variables. Grover\u27s algorithm running on a large quantum computer is expected to reduce the time to . As a building block, Grover\u27s algorithm requires an oracle , which is used to evaluate the quadratic equations at a superposition of all possible inputs. In this paper, we describe two different quantum circuits that provide this oracle functionality. As a corollary, we show that even a relatively small quantum computer with as little as 92 logical qubits is sufficient to break MQ instances that have been proposed for 80-bit pre-quantum security
Don\u27t throw your nonces out with the bathwater: Speeding up Dilithium by reusing the tail of y
No full textWe suggest a small change to the Dilithium signature scheme, that allows one to reuse computations between rejected nonces, for a speed-up in signing time.
The modification is based on the idea that, after rejecting on a too large , not all elements of the nonce are spent.
We swap the order of the checks; and if this -check fails, we only need to resample .
We provide a proof that shows that the modification does not affect the security of the scheme.
We present measurements of the performance of the modified scheme on AVX2, Cortex M4, and Cortex M3,
which show a speed-up ranging from 11% for Dilithium2 on M3 to 22% for Dilithium3 on AVX2
Sign in finite fields
Full text linkOften in cryptography one needs to make a consistent choice of square root in a finite field. We show that such a choice is equivalent to providing a reasonable sign function. Then we show that for (with odd prime and ) such a sign function exists if and only if is odd
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