Abstract. This paper proposes a fast parallel Montgomery multiplication algorithm based on Residue Number Systems (RNS). It is easy to construct a fast modular exponentiation by applying the algorithm repeatedly. To realize an efficient RNS Montgomery multiplication, the main contribution of this paper is to provide a new RNS base extension algorithm. Cox-Rower Architecture described in this paper is a hardware suitable for the RNS Montgomery multiplication. In this architecture, a base extension algorithm is executed in parallel by plural Rower units controlled by a Cox unit. Each Rower unit is a single-precision modular multiplier-and-accumulator, whereas Cox unit is typically a 7 bit adder. Although the main body of the algorithm processes numbers in an RNS form, efficient procedures to transform RNS to or from a radix representation are also provided. The exponentiation algorithm can, thus, be adapted to an existing standard radix interface of RSA cryptosystem.

Abstract. We proposed a fast parallel algorithm of Montgomery multiplication based on Residue Number Systems (RNS). An implementation of RSA cryptosystem using the RNS Montgomery multiplication is described in this paper. We discuss how to choose the base size of RNS and the number of parallel processing units. An implementation method using the Chinese Remainder Theorem (CRT) is also presented. An LSI prototype adopting the proposed Cox-Rower Architecture achieves 1024-bit RSA transactions in 4.2 msec without CRT and 2.4 msec with CRT, when the operating frequency is 80 MHz and the total number of logic gates is 333 KG for 11 parallel processing units.

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Securing information in communication networks is an important challenge in today's world. Quantum Key Distribution (QKD) can provide unique capabilities towards achieving this security, allowing intrusions to be detected and information leakage avoided. We report here a record high bit rate prototype QKD system providing a total of 878 Gbit of secure key data over a 34 day period corresponding to a sustained key rate of around 300 kbit/s. The system was deployed over a standard 45 km link of an installed metropolitan telecommunication fibre network in central Tokyo. The prototype QKD system is compact, robust and automatically stabilised, enabling key distribution during diverse weather conditions. The security analysis includes an efficient protocol, finite key size effects and decoy states, with a quantified key failure probability of ε = 10⁻¹⁰.

Effects of sex-relevant and sex-irrelevant facial features on the evaluation of facial gender were investigated. Participants rated masculinity of 48 male facial photographs and femininity of 48 female facial photographs. Eighty feature points were measured on each of the facial photographs. Using a generalized Procrustes analysis, facial shapes were converted into multidimensional vectors, with the average face as a starting point. Each vector was decomposed into a sex-relevant subvector and a sex-irrelevant subvector which were, respectively, parallel and orthogonal to the main male-female axis. Principal components analysis (PCA) was performed on the sex-irrelevant subvectors. One principal component was negatively correlated with both perceived masculinity and femininity, and another was correlated only with femininity, though both components were orthogonal to the male-female dimension (and thus by definition sex-irrelevant). These results indicate that evaluation of facial gender depends on sex-irrelevant as well as sex-relevant facial features.