1,032 research outputs found
Efficient software implementation of elliptic curves and bilinear pairings
Orientador: Júlio César Lopez HernándezTese (doutorado) - Universidade Estadual de Campinas, Instituto de ComputaçãoResumo: O advento da criptografia assimétrica ou de chave pública possibilitou a aplicação de criptografia em novos cenários, como assinaturas digitais e comércio eletrônico, tornando-a componente vital para o fornecimento de confidencialidade e autenticação em meios de comunicação. Dentre os métodos mais eficientes de criptografia assimétrica, a criptografia de curvas elÃpticas destaca-se pelos baixos requisitos de armazenamento para chaves e custo computacional para execução. A descoberta relativamente recente da criptografia baseada em emparelhamentos bilineares sobre curvas elÃpticas permitiu ainda sua flexibilização e a construção de sistemas criptográficos com propriedades inovadoras, como sistemas baseados em identidades e suas variantes. Porém, o custo computacional de criptossistemas baseados em emparelhamentos ainda permanece significativamente maior do que os assimétricos tradicionais, representando um obstáculo para sua adoção, especialmente em dispositivos com recursos limitados. As contribuições deste trabalho objetivam aprimorar o desempenho de criptossistemas baseados em curvas elÃpticas e emparelhamentos bilineares e consistem em: (i) implementação eficiente de corpos binários em arquiteturas embutidas de 8 bits (microcontroladores presentes em sensores sem fio); (ii) formulação eficiente de aritmética em corpos binários para conjuntos vetoriais de arquiteturas de 64 bits e famÃlias mais recentes de processadores desktop dotadas de suporte nativo à multiplicação em corpos binários; (iii) técnicas para implementação serial e paralela de curvas elÃpticas binárias e emparelhamentos bilineares simétricos e assimétricos definidos sobre corpos primos ou binários. Estas contribuições permitiram obter significativos ganhos de desempenho e, conseqüentemente, uma série de recordes de velocidade para o cálculo de diversos algoritmos criptográficos relevantes em arquiteturas modernas que vão de sistemas embarcados de 8 bits a processadores com 8 coresAbstract: The development of asymmetric or public key cryptography made possible new applications of cryptography such as digital signatures and electronic commerce. Cryptography is now a vital component for providing confidentiality and authentication in communication infra-structures. Elliptic Curve Cryptography is among the most efficient public-key methods because of its low storage and computational requirements. The relatively recent advent of Pairing-Based Cryptography allowed the further construction of flexible and innovative cryptographic solutions like Identity-Based Cryptography and variants. However, the computational cost of pairing-based cryptosystems remains significantly higher than traditional public key cryptosystems and thus an important obstacle for adoption, specially in resource-constrained devices. The main contributions of this work aim to improve the performance of curve-based cryptosystems, consisting of: (i) efficient implementation of binary fields in 8-bit microcontrollers embedded in sensor network nodes; (ii) efficient formulation of binary field arithmetic in terms of vector instructions present in 64-bit architectures, and on the recently-introduced native support for binary field multiplication in the latest Intel microarchitecture families; (iii) techniques for serial and parallel implementation of binary elliptic curves and symmetric and asymmetric pairings defined over prime and binary fields. These contributions produced important performance improvements and, consequently, several speed records for computing relevant cryptographic algorithms in modern computer architectures ranging from embedded 8-bit microcontrollers to 8-core processorsDoutoradoCiência da ComputaçãoDoutor em Ciência da Computaçã
Quantum transmission in disordered insulators: random matrix theory and transverse localization
We consider quantum interferences of classically allowed or forbidden
electronic trajectories in disordered dielectrics. Without assuming a directed
path approximation, we represent a strongly disordered elastic scatterer by its
transmission matrix . We recall how the eigenvalue distribution of
can be obtained from a certain ansatz leading to a
Coulomb gas analogy at a temperature which depends on the system
symmetries. We recall the consequences of this random matrix theory for
quasi-- insulators and we extend our study to microscopic three dimensional
models in the presence of transverse localization. For cubes of size , we
find two regimes for the spectra of as a function of the
localization length . For , the eigenvalue spacing
distribution remains close to the Wigner surmise (eigenvalue repulsion). The
usual orthogonal--unitary cross--over is observed for {\it large} magnetic
field change where denotes the flux
quantum. This field reduces the conductance fluctuations and the average
log--conductance (increase of ) and induces on a given sample large
magneto--conductance fluctuations of typical magnitude similar to the sample to
sample fluctuations (ergodic behaviour). When is of the order of theComment: Saclay-S93/025 Email: [email protected]
Efficient and Secure ECDSA Algorithm and its Applications: A Survey
Public-key cryptography algorithms, especially elliptic curve cryptography (ECC)and elliptic curve digital signature algorithm (ECDSA) have been attracting attention frommany researchers in different institutions because these algorithms provide security andhigh performance when being used in many areas such as electronic-healthcare, electronicbanking,electronic-commerce, electronic-vehicular, and electronic-governance. These algorithmsheighten security against various attacks and the same time improve performanceto obtain efficiencies (time, memory, reduced computation complexity, and energy saving)in an environment of constrained source and large systems. This paper presents detailedand a comprehensive survey of an update of the ECDSA algorithm in terms of performance,security, and applications
Improved quantum circuits for elliptic curve discrete logarithms
We present improved quantum circuits for elliptic curve scalar
multiplication, the most costly component in Shor's algorithm to compute
discrete logarithms in elliptic curve groups. We optimize low-level components
such as reversible integer and modular arithmetic through windowing techniques
and more adaptive placement of uncomputing steps, and improve over previous
quantum circuits for modular inversion by reformulating the binary Euclidean
algorithm. Overall, we obtain an affine Weierstrass point addition circuit that
has lower depth and uses fewer gates than previous circuits. While previous
work mostly focuses on minimizing the total number of qubits, we present
various trade-offs between different cost metrics including the number of
qubits, circuit depth and -gate count. Finally, we provide a full
implementation of point addition in the Q# quantum programming language that
allows unit tests and automatic quantum resource estimation for all components.Comment: 22 pages, to appear in: Int'l Conf. on Post-Quantum Cryptography
(PQCrypto 2020
Suppressing the Cosmological Constant in Non-Supersymmetric Type I Strings
We construct non-supersymmetric type I string models which correspond to
consistent flat-space solutions of all classical equations of motion. Moreover,
the one-loop vacuum energy is naturally fixed by the size of compact extra
dimensions which, in the two-dimensional case, can be lowered to a fraction of
a millimetre. This class of models has interesting non-abelian gauge groups and
can accommodate chiral fermions. In the large radius limit, supersymmetry is
recovered in the bulk, while D-brane excitations, although non-supersymmetric,
exhibit Fermi-Bose degeneracy at all mass levels. We also give some evidence
for a suppression of higher-loop corrections to the vacuum energy.Comment: 22 pages, 4 figures. v2 references adde
Halving on Binary Edwards Curves
Edwards curves have attracted great interest for their efficient addition and doubling formulas. Furthermore, the addition formulas are strongly unified or even complete, i.e., work without change for all inputs. In this paper, we propose the first halving algorithm on binary Edwards curves, which can be used for scalar multiplication. We present a point halving algorithm on binary Edwards curves in case of . The halving algorithm costs about , which is slower than the doubling one. We also give a theorem to prove that the binary Edwards curves have no minimal two-torsion in case of , and we briefly explain how to achieve the point halving algorithm using an improved algorithm in this case. Finally, we apply our halving algorithm in scalar multiplication with -coordinate using Montgomery ladder
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