| 1. |
- Afanassiev, Valentine, et al.
(författare)
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Fast message authentication using efficient polynomial evaluation
- 1997
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Ingår i: Fast Software Encryption : 4th International Workshop, FSE 1997, Proceedings - 4th International Workshop, FSE 1997, Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 3540632476 - 9783540632474 ; 1267, s. 190-204
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Konferensbidrag (refereegranskat)abstract
- Message authentication codes (MACs) using polynomial evaluation have the advantage of requiring a very short key even for very large messages. We describe a low complexity software polynomial evaluation procedure, that for large message sizes gives a MAC that has about the same low software complexity as for bucket hashing but requires only small keys and has better security characteristics.
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| 2. |
- Asklund, Ulf, et al.
(författare)
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The unified extensional versioning model
- 1999
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Ingår i: System Configuration Management - 9th International Symposium, SCM 1999, Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 354066484X - 9783540664840 ; 1675, s. 100-122
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Konferensbidrag (refereegranskat)abstract
- Versioning of components in a system is a well-researched field where various adequate techniques have already been established. In this paper, we look at how versioning can be extended to cover also the structural aspects of a system. There exist two basic techniques for versioning - intentional and extensional - and we propose a unified extensional versioning model for versioning of both components and structure in the same way. The unified model is described in detail and three different policies that can be implemented on top of the general model are exemplified/illustrated by three prototype tools constructed by the authors. The model is analysed with respect to the number of versions and con- figurations it generates and has to manage. Finally, the unified extensional model is compared to more traditional intentional models on some important parameters. The conclusions are that the unified model is indeed viable. It not only pro- vides the functionality offered by the intentional model with respect to flexibility during development and management of combinatoric complexity, but also offers a framework for management of configurations that enables systems to provide much more advanced support than is commonly available.
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| 3. |
- Bocharova, Irina, et al.
(författare)
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Fast exponentation in cryptography
- 1995
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Ingår i: Applied Algebra, Algebraic Algorithms and Error-Correcting Codes/Lecture notes in computer science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 3540601147 ; 948, s. 146-157
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of minimizing the number of multiplications in computing f(x)=x n , where n is an integer and x is an element of any ring. We present new methods which reduce the average number of multiplications comparing with well-known methods, such as the binary method and the q-ary method. We do not compare our approach with algorithms based on addition chains since our approach is intended for cryptosystems with large exponent n and the complexity of constructing the optimal addition chain for such n is too high. We consider the binary representation for the number n and simplify exponentiation by applying ideas close to ideas exploited in data compression. Asymptotical efficiency of the new algorithms is estimated and numerical results are given.
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| 4. |
- Ekdahl, Patrik, et al.
(författare)
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Incremental authentication of tree-structured documents
- 1999
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Ingår i: Information and Communication Security : 2nd International Conference, ICICS 1999, Proceedings - 2nd International Conference, ICICS 1999, Proceedings. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 3540666826 - 9783540666820 - 9783540479420 ; 1726, s. 275-283
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Konferensbidrag (refereegranskat)abstract
- A new message authentication code (MAC) is described that exploits the tree structure present in many modern document formats, e.g. SGML and XML. The new code supports incremental updating of the cryptographic checksum in the process of making incremental changes to the document. Theoretical bounds on the probability of a successful substitution attack are derived. Through experimental results we demonstrate that for randomly chosen messages the success probability of such an attack will be smaller and is easily identified.
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| 5. |
- Eklund, Patrik, 1958-, et al.
(författare)
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Unravelling the thrill of metric image spaces
- 1999
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Ingår i: Lecture Notes in Computer Science. - : Springer Berlin/Heidelberg. - 0302-9743 .- 1611-3349. ; 1568, s. 275-285
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we focus on distances between textures. and develop metrics on image spaces in contexts of image transformations. Given a metric on the range space, we can generate the initial topology for the domain space. For this topology we can obtain a corresponding metric using well-known metrization constructions, also providing granularity of the metrics. Examples are drawn front the Spatial Gray Level Dependency (SGLD) transformation and the application domain is texture recognition in medical imaging.
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| 6. |
- Engdahl, Karin, et al.
(författare)
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On the theory of low-density convolutional codes
- 1999
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Ingår i: Lecture Notes in Computer Science/Applied Algebra, Algebraic Algorithms and Error-Correcting Codes. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783540667230 ; 1719, s. 77-86
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Konferensbidrag (refereegranskat)abstract
- We introduce and analyze a new statistical ensemble of lowdensity parity-check convolutional (LDC) codes. The result of the analysis are bounds, such as a lower bound for the free distance and upper bounds for the burst error probability of the LDC codes.
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| 7. |
- Hedin, Görel, et al.
(författare)
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Product configuration using object oriented grammars
- 1998
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Ingår i: System Configuration Management - ECOOP 1998 SCM-8 Symposium, Proceedings. - 1611-3349 .- 0302-9743. - 3540647333 - 9783540647331 ; 1439, s. 107-126
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Konferensbidrag (refereegranskat)abstract
- This paper presents a technique for product configuration modelling based on object-orientation and attribute grammars. The technique allows efficient interactive configurator tools to be generated for specified product families. Additional benefits include a high degree of checkability, early validation, readability, and reusability. The technique is particularly aimed at mass-customization products and an example concerning the mechanical configuration of plate heat exchangers is used to demonstrate its benefits.
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| 8. |
- Helleseth, Tor, et al.
(författare)
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Universal hash functions from exponential sums over finite fields and Galois rings
- 1996
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Ingår i: Advances in Cryptology / Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 1611-3349 .- 0302-9743. - 9783540615125 ; 1109, s. 31-44
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Konferensbidrag (refereegranskat)abstract
- In this paper new families of strongly universal hash functions, or equivalently, authentication codes, are proposed. Their parameters are derived from bounds on exponential sums over finite fields and Galois rings. This is the first time hash families based upon such exponential sums have been considered. Their performance improves the previously best known constructions and they can be made general in their choice of parameters. Furthermore, the constructions are suitable both for hardware and software implementations. The latter is an aspect that is significant and has been considered in several recent papers.
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| 9. |
- Johansson, Thomas
(författare)
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Bucket hashing with a small key size'
- 1997
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Ingår i: Advances in Cryptology / Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783540629757 ; 1233, s. 149-162
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Konferensbidrag (refereegranskat)abstract
- In this paper we consider very fast evaluation of strongly universal hash functions, or equivalently, authentication codes. We show how it is possible to modify some known families of hash functions into a form such that the evaluation is similar to “bucket hashing”, a technique for very fast hashing introduced by Rogaway. Rogaway’s bucket hash family has a huge key size, which for common parameter choices can be more than a hundred thousand bits. The proposed hash families have a key size that is close to the key size of the theoretically best known constructions, typically a few hundred bits, and the evaluation has a time complexity that is similar to bucket hashing.
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| 10. |
- Johansson, Thomas, et al.
(författare)
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Fast correlation attacks based on turbo code techniques
- 1999
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Ingår i: Advances in Cryptology / Lecture Notes in Computer Science. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 0302-9743 .- 1611-3349. - 9783540663478 ; 1666, s. 181-197
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Konferensbidrag (refereegranskat)abstract
- This paper describes new methods for fast correlation attacks on stream ciphers, based on techniques used for constructing and decoding the by now famous turbo codes. The proposed algorithm consists of two parts, a preprocessing part and a decoding part. The preprocessing part identifies several parallel convolutional codes, embedded in the code generated by the LFSR, all sharing the same information bits. The decoding part then finds the correct information bits through an iterative decoding procedure. This provides the initial state of the LFSR.
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