669 research outputs found
Performance Analysis of Modified SHA-3
No full textAbstractSecurity services have become an inseparable feature of almost all digital transactions. A crucial module of these scheme isintegrity, which is performed using a cryptographic hash function. Secure Hash Algorithm can be an efficient hashing technique.SHA-3 is the most recent and efficient Secure Hash Algorithm. Keccak has been chosen as the official algorithm for SHA-3 in2012. In this paper we propose a modification on the design of Secure Hash Algorithm (SHA-3) on Xilinx Field ProgrammableGate Array (FPGA) device. In order to provide reliable architecture for this algorithm, a concurrent error tolerant scheme forSHA-3 is used. A system based on the combination of SHA-3 and error tolerant scheme is also described. Simulation resultsshows, an efficiency in area and delay of SHA-3 designs
Security and usability of standard has hfunctions, in particular MD-5, SHA-1 and SHA-2
No full textTitle: Security and usability of standard hash functions, in particular MD-5, SHA-1 and SHA-2 Author: Galaczová Barbora Department: Department of Algebra Supervisor: Doc. RNDr. Tůma Jiří, DrSc., Department of Algebra Consultant: Ing. Budiš Petr, Ph.D. Abstract: In the present work we try to digestedly describe standard hash functions, in particular MD-5, SHA-1 and SHA-2. We describe resume of existing attacks on these hash functions. We closely focused on MD-5 collision attacks, because the other hash function collision attacks result from these. Next we describe posibilities of practical usage of hash function collisions, in particular into the qualified certificates area and possible threats. At the end to the present work we describe new hash functions, which could replace current hash functions. This work also contains software to calculate MD-5 hash and search it`s collisions. The software is based on method invented by Czech cryptoanalytist Vlastimil Klíma. Keywords: hash function, collision, qualified certificate, security
Cryptanalysis of Dynamic SHA(2)
No full textIn this paper, we analyze the hash functions Dynamic SHA and Dynamic SHA2, which have been selected as first round candidates in the NIST hash function competition. These hash functions rely heavily on data-dependent rotations, similar to certain block ciphers, e.g., RC5. Our analysis suggests that in the case of hash functions, where the attacker has more control over the rotations, this approach is less favorable than in block ciphers. We present practical, or close to practical, collision attacks on both Dynamic SHA and Dynamic SHA2. Moreover, we present a preimage attack on Dynamic SHA that is faster than exhaustive search. © 2009 Springer-Verlag Berlin Heidelberg.sponsorship: Supported by the Swiss National Science Foundation, project no. 113329. This author was supported by the France Telecom chaire. F.W.O. Research Assistant, Fund for Scientific Research Flander s (Belgium) (Swiss National Science Foundation|113329, France Telecom chaire, Scientific Research)status: Publishe
Design & Characterization of SHA 3- 256 Bit IP Core
No full textAbstractIn the era of internet and computer networking the need for security have increased rapidly. Various crypto algorithms are used for secured data transmission and reception through the network, of which hash function possess a key role in various cryptographic protocols. Keccak algorithm is the winner of SHA-3 competition conducted by NIST. SHA-3 consists of different variant such as 224, 256, 384 and 512 bit. This paper discuss the design and implementation of SHA-3 256- bit core. The core is designed using Verilog HDL and prototyped using Xilinx® Virtex®-6FPGA
Uma solução de autenticação fim a fim para o LDP (Label Distribution Protocol)
No full textDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação.Este trabalho propõe uma solução de autenticação para o protocolo LDP (Label Distribution Protocol) que tem por objetivo autenticar, em um escopo fim a fim, o estabelecimento de um LSP (Label Switching Path) entre um LSR (Label Switching Router) de Ingresso e o seu respectivo LSR de Egresso. Objetiva-se suprir a deficiência do protocolo LDP de não possuir um mecanismo de autenticação fim a fim definido, aplicável entre LSRs não-adjacentes. Conforme foi verificado pelo levantamento de trabalhos correlatos, atualmente é desconhecida uma solução de autenticação semelhante, que efetivamente atenda o propósito de autenticar num escopo fim a fim, o estabelecimento de LSPs no protocolo LDP. Dessa forma a solução deste trabalho é inédita no seu escopo de aplicação. A solução foi planejada para ambientes onde LSPs atravessam múltiplos domínios externos, não confiáveis entre si, e que por isso necessitam de um mecanismo de autenticação durante o estabelecimento dos LSPs. A solução faz uso de um mecanismo de autenticação, baseado em criptografia assimétrica (chave pública e privada), anexado a cada mensagem LDP. Este mecanismo possibilita ao LSR receptor verificar e autenticar o originador da mensagem LDP. Adicionalmente a solução provê integridade de dados através de um mecanismo de resumo de mensagens (hash) e também protege contra ataques de repetição através da inserção de um nonce às mensagens LDP
Maximizing the Potential of Custom RISC-V Vector Extensions for Speeding up SHA-3 Hash Functions
No full textSHA-3 is considered to be one of the most secure standardized hash functions. It relies on the Keccak-f[1 600] permutation, which operates on an internal state of 1 600 bits, mostly represented as a 5 x 5 x 64-bit matrix. While existing implementations process the state sequentially in chunks of typically 32 or 64 bits, the Keccak-f[1 600] permutation can benefit a lot from speedup through parallelization. This paper is the first to explore the full potential of parallelization of Keccak-f[1 600] in RISC-V based processors through custom vector extensions on 32-bit and 64-bit architectures. We analyze the Keccak permutation, composed of five different step mappings, and propose ten custom vector instructions to speed up the computation. We realize these extensions in a SIMD processor described in System Verilog. We compare the performance of our designs to existing architectures based on vectorized application-specific instruction set processors (ASIP). We show that our designs outperform all related work in throughput due to our carefully selected custom vector instructions.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
Security Reductions of the Second Round SHA-3 Candidates
No full text© 2011, Springer-Verlag Berlin Heidelberg. In 2007, the US National Institute for Standards and Technology announced a call for the design of a new cryptographic hash algorithm in response to vulnerabilities identified in existing hash functions, such as MD5 and SHA-1. NIST received many submissions, 51 of which got accepted to the first round. At present, 14 candidates are left in the second round. An important criterion in the selection process is the SHA-3 hash function security and more concretely, the possible security reductions of the hash function to the security of its underlying building blocks. While some of the candidates are supported with firm security reductions, for most of the schemes these results are still incomplete. In this paper, we compare the state of the art provable security reductions of the second round SHA-3 candidates. Surprisingly, we derive some security bounds from the literature, which the hash function designers seem to be unaware of. Additionally, we generalize the well-known proof of collision resistance preservation, such that all SHA-3 candidates with a suffix-free padding are covered.sponsorship: This work has been funded in part by the IAP Program P6/26 BCRYPT of the Belgian State (Belgian Science Policy), and in part by the European Commission through the ICT program under contract ICT-2007- 216676 ECRYPT II. The first author is supported by a Ph.D. Fellowship from the Flemish Research Foundation (FWO-Vlaanderen). The second author is supported by a Ph.D. Fellowship from the Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen). (IAP of the Belgian State (Belgian Science Policy|P6/26 BCRYPT, European Commission through the ICT program|ICT-2007- 216676, Flemish Research Foundation (FWO-Vlaanderen), Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen))status: Publishe
the research about artistic contributions of the China Opera \ue2 Sha Gou Ji \ue2
No full textThe dissertation is the research about artistic contributions of the China Opera \ue2 Sha Gou Ji \ue2 , and discuss the related questions, external social culture phenomenon. The artistic contributions are discussion about the plot, subject, figure, script. External social culture phenomenon is the discussion about the social culture meaning which is \ue2 Sha Gou Ji \ue2 present point\uef\ubchousehold morality.
The dissertation is including six research chapters.
The First Chapter\uef\ubcIntroduction
To introduce the research cause, research method, research scope.
The Second\uef\ubcThe author and the edition
To conclude the author and the edition, and compare the south opera \ue2 Sha Gou Ji \ue2 to essay \ue2Sha Gou Quan Fu\ue2
The Third Chapter\uef\ubcThe plot subject
Research about the construction and what thought want to communicate.
The Forth Chapter\uef\ubcAnalysis about the major roles
Analysis about the major roles , and discussion about the personal characteristic from each role.
The Fifth Chapter\uef\ubcLanguage art
Research about the language feature , rhetoric skill. Then we can understand the artistry.
The Sixth Chapter\uef\ubcConclusion
The research conclusion from each chapters stud
rNying ma rgyud 'bum [Vol. 27: sha]
No full textGENERAL Shelfmark: naLibrary, Location: Pagar MonasteryCONTENT Author: na (STM)Title: rNying ma rgyud 'bum [Vol. 27: sha] (STM)Subjects: Buddhist Tantric LiteratureComment: A para-canonical collection containing the Tantric literature of the rNying ma school of Tibetan Buddhism. Similar to the other known 46-volume Bhutanese editions of the rNying ma rgyud 'bum.PHYSICAL DESCRIPTION Cover, Binding: looseMaterials, Support: paperFormat: width=63.0cm; height=17.0cmNumber of Volumes: 46Inks, Colours: black ink (main text), red ink (frames), golden ink (fol. 1v of each vol.)Comment: Apart from the first few folios, 7 lines per page.PRODUCTION / PROVENANCE / HISTORY Date: probably 18th centuryLanguage / Script: Tibetan / TibetanComment: In 29.02.2012 big portions of the Pagar Monastery were destroyed by fire and with it also this rNying ma rgyud 'bum set.SERVICE DATA Record created: 2014-04-22T10:24:58.636ZRecord modified: 2014-07-03T13:11:08.049ZRecord migrated: 2020-11-04T13:18:23Creator: Almogi, OrnaMigrated from: sfb_mssentry_0000060
The rise of temporary employment in Japan: Legalisation and expansion of a non-regular employment form
No full textThis discussion paper examines the institutionalization process of a non-regular employment form especially focusing on the establishment of the temporary dispatching work (haken) system. The institutionalization process of the haken system can be divided into three periods: delegalisation (1947-86), legalisation (1986-99), and diffusion (1999-). Declining labor strength, the emergence of deregulation bodies, and the changing attitude of the Ministry of Labor (MHLW) characterize the legal developments. Together with the liberalization of private job placement and the expansion of fixed-term contract work, temporary work became an important sources of flexible and skilled labor, and expanded more rapidly than other employment forms in the late 90s. In this development, temporary help firms started to reframe their business as 'personnel services,' and have positioned themselves to replace the traditional firm-internal supply of mobile employees such as shukkô and tenseki with external dispatched employees of temporary help firms. --Japan,temporary work,non-regular employment,labor market,(de-)regulation
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