181 research outputs found

    Parallel integer relation detection: techniques and applications

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    Strongly universal string hashing is fast

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    We present fast strongly universal string hashing families: they can process data at a rate of 0.2 CPU cycle per byte. Maybe surprisingly, we find that these families---though they require a large buffer of random numbers---are often faster than popular hash functions with weaker theoretical guarantees. Moreover, conventional wisdom is that hash functions with fewer multiplications are faster. Yet we find that they may fail to be faster due to operation pipelining. We present experimental results on several processors including low-powered processors. Our tests include hash functions designed for processors with the Carry-Less Multiplication (CLMUL) instruction set. We also prove, using accessible proofs, the strong universality of our families.Comment: Software is available at http://code.google.com/p/variablelengthstringhashing/ and https://github.com/lemire/StronglyUniversalStringHashin

    Generalised Mersenne Numbers Revisited

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    Generalised Mersenne Numbers (GMNs) were defined by Solinas in 1999 and feature in the NIST (FIPS 186-2) and SECG standards for use in elliptic curve cryptography. Their form is such that modular reduction is extremely efficient, thus making them an attractive choice for modular multiplication implementation. However, the issue of residue multiplication efficiency seems to have been overlooked. Asymptotically, using a cyclic rather than a linear convolution, residue multiplication modulo a Mersenne number is twice as fast as integer multiplication; this property does not hold for prime GMNs, unless they are of Mersenne's form. In this work we exploit an alternative generalisation of Mersenne numbers for which an analogue of the above property --- and hence the same efficiency ratio --- holds, even at bitlengths for which schoolbook multiplication is optimal, while also maintaining very efficient reduction. Moreover, our proposed primes are abundant at any bitlength, whereas GMNs are extremely rare. Our multiplication and reduction algorithms can also be easily parallelised, making our arithmetic particularly suitable for hardware implementation. Furthermore, the field representation we propose also naturally protects against side-channel attacks, including timing attacks, simple power analysis and differential power analysis, which is essential in many cryptographic scenarios, in constrast to GMNs.Comment: 32 pages. Accepted to Mathematics of Computatio

    Basic key exchange protocols for secret key cryptosystems under CRYMPIX library

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    Thesis (Master)--Izmir Institute of Technology, Computer Engineering, Izmir, 2007Includes bibliographical references (leaves: 47-48)Text in English; Abstract: Turkish and Englishviii, 50 leavesKey exchange protocols are developed in order to overcome the key distribution problem of symmetrical cryptosystems. These protocols which are based on various algebraic domains are different implementations of public-key cryptography. In this thesis, the basic key exchange protocols are reviewed and CRYMPIX implementations of them are provided. CRYMPIX has a portable structure that provides platform independence for generated code. Hence, the implemented key exchange mechanisms are suitable to be used on different hardware and software platforms
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