In this paper, we show that a verifier-based password authentication scheme and two remote user authentication schemes are insecure against several active attacks. These results demonstrate that no more password authentication schemes should be constructed with such ad-hoc methods, i.e, the formal design methodology using provable security should be employed.

A proxy signature enables an original signer to delegate its signing capability to a proxy signer and the proxy signer can sign a message on behalf of the original signer. Later, anyone can verify the validity of proxy signatures. The “public-verifiable” property of the proxy signature is not suitable in some applications in which a proxy signed message may be personally or commercially sensitive. A designated verifier proxy signature scheme is suitable for these environments. In this paper, we propose a provably secure short designated verifier proxy signature scheme in the random oracle model under the Bilinear Diffie–Hellman

In ICISC 2007, Comuta and others showed that among the methods for constructing pairing­friendly curves, those using cyclotomic polynomials, that is, the Brezing­Weng method and the Freeman­Scott­Teske method, are affected by Cheon's algorithm. This paper proposes a method for searching parameters of pairing­friendly elliptic curves that induces minimal security loss by Cheon's algorithm. We also provide a sample set of parameters of BN­curves, FST­curves, and KSS­curves for pairing­based cryptography.

Certificateless cryptography eliminates the need of certificates in public key cryptosystems and solves the inherent key escrow problem in identity-based cryptosystems. An aggregate signature scheme is a signature scheme which allows to aggregate n signatures on n distinct messages from n distinct users into a single signature. Recently, Zhang and Zhang proposed a certificateless aggregate signature scheme provably secure in the random oracle model under the Computational Diffie-Hellman assumption. In this paper, we propose a novel fundamental security requirement for certificateless aggregate signature schemes, called coalition resistance, by presenting coalition attacks on Zhang-Zhang's scheme.

The use of radio frequency identification (RFID) has become widespread in a range of applications. International standards of RFID technology are actively being developed for securing RFID communications. Recently, ISO/IEC WD 29167-6 proposed three security protocols, namely Protocol 1, 2 and 3. In this letter, we show that Protocol 1 - mutual authentication and secure communication in security mode - is vulnerable to a man-in-the-middle attack. We also propose a countermeasure against the attack.

We explore how the topology of spacetime fabric is encoded into the local structure of Riemannian metrics using
the gauge theory formulation of Euclidean gravity. In part I, we provide a rigorous mathematical foundation to
prove that a general Einstein manifold arises as the sum of SU(2)_L Yang-Mills instantons and SU(2)_R anti-
instantons where SU(2)_L and SU(2)_R are normal subgroups of the four-dimensional Lorentz group Spin(4) =
SU(2)_L x SU(2)_R. Our proof relies only on the general properties in four dimensions: The Lorentz group
Spin(4) is isomorphic to SU(2)_L x SU(2)_R and the six-dimensional vector space of two-forms splits canonically
into the sum of three-dimensional vector spaces of self-dual and anti-self-dual two-forms. Consolidating these
two, it turns out that the splitting of Spin(4) is deeply correlated with the decomposition of two-forms on four-
manifold which occupies a central position in the theory of four-manifolds.

Around the globe several observatories are seeking the first direct detection of gravitational waves (GWs). These
waves are predicted by Einstein's General Theory of Relativity [Einstein, A., Annalen der Physik 49, 769-822
(1916)] and are generated e.g. by black-hole binary systems [Sathyaprakash, B. S. and Schutz, B. F., Living
Rev. Relativity 12, 2 (2009)]. Current GW detectors are Michelson-type kilometer-scale laser interferometers
measuring the distance changes between in vacuum suspended mirrors. The sensitivity of these detectors at
frequencies above several hundred hertz is limited by the vacuum (zero-point) fluctuations of the
electromagnetic field. A quantum technology - the injection of squeezed light [Caves, C. M., Phys. Rev. D 23,
1693-1708 (1981)] - offers a solution to this problem. Here we demonstrate the squeezed-light enhancement
of GEO600, which will be the GW observatory operated by the LIGO Scientific Collaboration in its search for GWs
for the next 3-4 years. GEO600 now operates with its best ever sensitivity, which proves the usefulness of
quantum entanglement and the qualification of squeezed light as a key technology for future GW astronomy.

Finger vein recognition has been adopted due to its high recognition rate and the invisibility of vein in visible light.
However, because a finger vein pattern is not distinctive due to light scattering in the skin layer, the localization of a
finger vein pattern region using an image processing algorithm is a difficult procedure. Also, optical blurring increases
these difficulties. We propose a new finger vein image restoration method to deal with skin scattering and optical
blurring. Our research is novel in three ways compared to previous studies. Firstly, the amount of optically blurring of
a finger vein image is measured based on the average gradient of the orthogonal profile of a finger edge. Secondly,
the accurate point spread function (PSF) of optical blurring is adaptively determined based on the orthogonal profile of
a finger edge. Thirdly, by using a constrained least square (CLS) filter and optimized parameters in terms of the
lowest error of finger vein recognition, the restoration of a skin scattered and optically blurred finger vein pattern was
performed. Experimental results show that the equal error rate (EER) of finger vein recognition with restoration was
reduced by as much as 3.14% (5.05% ? 1.91%) compared to the EER without restoration.

We show that every gravitational instantons are SU(2) Yang-Mills instantons on a Ricci-flat four manifold although
the reverse is not necessarily true. It is shown that gravitational instantons satisfy exactly the same self-duality
equation of SU(2) Yang-Mills instantons on the Ricci-flat manifold determined by the gravitational instantons
themselves. We explicitly check the correspondence with several examples and discuss their topological properties.