1,721,093 research outputs found
New results on the genetic cryptanalysis of TEA and reduced-round versions of XTEA
Get PDFCongress on Evolutionary Computation. Portland, USA, 19-23 June 2004Recently, a simple way of creating very efficient distinguishers for cryptographic primitives such as block ciphers or hash functions, was presented by the authors. Here, this cryptanalysis attack is shown to be successful when applied over reduced round versions of the block cipher XTEA. Additionally, a variant of this genetic attack is introduced and its results over TEA shown to be the most powerful published to date
Cryptanalysis of the ANSI X9.52 CBCM Mode
No full text. In this paper we cryptanalyze the proposed (almost accepted) ANSI X9.52 CBCM mode. The CBCM mode is a triple-DES CBC variant which was designed against powerful attacks which control intermediate feedbacks for the benefit of the attacker. For this purpose, it uses intermediate feedbacks that the attacker cannot control, choosing them as a keyed OFB stream, independent of the plaintexts and ciphertexts. The attack we describe finds a way to use even this kind of feedback for the benefit of the attacker. It requires a single chosen ciphertext of 2 65 blocks and 2 58 complexity of analysis. We also describe an adaptive known-IV related-key attack which find one of three 56-bit keys requiring one known plaintext encrypted under 2 33 different but related keys with 2 57 complexity of analysis. Key words. Cryptanalysis. ANSI X9.52. Modes of operation. CBCM mode. Triple-DES. Multiple Encryption. 1 Introduction The Data Encryption Standard (DES) [14] has been the subject of intense ..
Distributed human computation framework for linked data co-reference resolution
Get PDFDistributed Human Computation (DHC) is a technique used to solve computational problems by incorporating the collaborative effort of a large number of humans. It is also a solution to AI-complete problems such as natural language processing. The Semantic Web with its root in AI is envisioned to be a decentralised world-wide information space for sharing machine-readable data with minimal integration costs. There are many research problems in the Semantic Web that are considered as AI-complete problems. An example is co-reference resolution, which involves determining whether different URIs refer to the same entity. This is considered to be a significant hurdle to overcome in the realisation of large-scale Semantic Web applications. In this paper, we propose a framework for building a DHC system on top of the Linked Data Cloud to solve various computational problems. To demonstrate the concept, we are focusing on handling the co-reference resolution in the Semantic Web when integrating distributed datasets. The traditional way to solve this problem is to design machine-learning algorithms. However, they are often computationally expensive, error-prone and do not scale. We designed a DHC system named iamResearcher, which solves the scientific publication author identity co-reference problem when integrating distributed bibliographic datasets. In our system, we aggregated 6 million bibliographic data from various publication repositories. Users can sign up to the system to audit and align their own publications, thus solving the co-reference problem in a distributed manner. The aggregated results are published to the Linked Data Cloud
Cryptanalysis of Multiple Modes of Operation
No full textIn recent years, several new attacks on DES were introduced. These attacks have led researchers to suggest stronger replacements for DES, and in particular new modes of operation for DES. The most popular new modes are triple DES variants, which are claimed to be as secure as triple DES. To speed up hardware implementations of these modes, and to increase the avalanche, many suggestions apply several standard modes sequentially. In this paper we study these multiple (cascade) modes of operation. This study shows that many multiple modes are much weaker than multiple DES, and their strength is comparable to a single DES.
We conjecture that operation modes should be designed around an underlying cryptosystem without any attempt to use intermediate data as feedback, or to mix the feedback into an intermediate round. Thus, in particular, triple DES used in CBC mode is more secure than three single DES's used in triple CBC mode. Alternatively, if several encryptions are applied to each block, the best choice is to concatenate them to one long encryption, and build the mode of operation around it
Cryptanalysis of the ANSI X9.52 CBCM Mode
No full text. In this paper we cryptanalyze the proposed (almost accepted) ANSI X9.52 CBCM mode. The CBCM mode is a triple-DES CBC variant which was designed against powerful attacks which control intermediate feedbacks for the benefit of the attacker. For this purpose, it uses intermediate feedbacks that the attacker cannot control, choosing them as a keyed OFB stream, independent of the plaintexts and ciphertexts. The attack we describe finds a way to use even this kind of feedback for the benefit of the attacker. It requires a single chosen ciphertext of 2 65 blocks and 2 58 complexity of analysis. We also describe an adaptive known-IV related-key attack which find one of three 56-bit keys requiring one known plaintext encrypted under 2 33 different but related keys with 2 57 complexity of analysis. Key words. Cryptanalysis. ANSI X9.52. Modes of operation. CBCM mode. Triple-DES. Multiple Encryption. 1 Introduction The Data Encryption Standard (DES) [14] has been the subject of intense ..
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