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An interoperable cross-context architecture to manage distributed personal e-Health information KU Leuven
Towards Security Notions for White-Box Cryptography KU Leuven
While code obfuscation attempts to hide certain characteristics of a program independently of an application, white-box cryptography (WBC) specifically focuses on software implementations of cryptographic primitives in an application. The aim of WBC is to resist attacks from an adversary having access to some 'executable' code with an embedded secret key. WBC, if possible, would have several applications. However, unlike obfuscation, it lacks a ...
Finding Collisions for a 45-Step Simplified HAS-V KU Leuven
Recent attacks on hash functions start by constructing a differential characteristic. By finding message pairs that satisfy this characteristic, a collision can be found. This paper describes the method of De Cannière and Rechberger to construct generalized characteristics for SHA-1 in more detail. This method is further generalized and applied to a simplified variant of the HAS-V hash function. Using these techniques, a characteristic for 45 ...
Improved Distinguishing Attacks on HC-256 KU Leuven
The software-efficient stream cipher HC-256 was proposed by Wu at FSE 2004. Due to its impressive performance, the cipher was also a well-received entrant to the ECRYPT eSTREAM competition. The closely related stream cipher HC-128, also designed by Wu, went on to find a place in the final portfolio of the eSTREAM contest. The cipher HC-256 is word-oriented, with 32 bits in each word, and uses a 256-bit key and a 256-bit IV. Since HC-256 was ...
Offline NFC Payments with Electronic Vouchers KU Leuven
© 2009 ACM. In this paper a practical offline payment system based on digital vouchers using Near Field Communication (NFC) in mobile phones is presented. This work was performed within the scope of the IBBT NFC-Voucher project. The goal of the project is to assess the feasibility of such a system, from a technical and security perspective, using tangible NFC devices such as the Nokia 6131 NFC mobile phone. This involved an in-depth technical ...
Empirical Comparison of Side Channel Analysis Distinguishers on DES in Hardware KU Leuven
Side channel analysis attacks exploit the information leakage of a cryptographic device to lay hands on the secret information that is processed. Several statistical means to extract this information have been proposed since the onset of the research area. In this paper we perform a fair empirical comparison of several side channel analysis distinguishers on a hardware implementation of the Data Encryption Standard. ©2009 IEEE.
Practical Collisions for EnRUPT KU Leuven
The EnRUPT hash functions were proposed by O'Neil, Nohl and Henzen [5] as candidates for the SHA-3 competition, organised by NIST [4]. The proposal contains seven concrete hash functions, each having a different digest length. We present a practical collision attack on each of these seven EnRUPT variants. The time complexity of our attack varies from 2 36 to 2 40 round computations, depending on the EnRUPT variant, and the memory requirements ...
Universally Composable Adaptive Priced Oblivious Transfer KU Leuven
An adaptive k-out-of-N Priced Oblivious Transfer (POT) scheme is a two-party protocol between a vendor and a buyer. The vendor sells a set of messages m 1 , ⋯ ,m N with prices p 1 , ⋯ , p N . In each transfer phase i=1, ⋯ , k, the buyer chooses a selection value σ i {1, ⋯ ,N} and interacts with the vendor to buy message m σi in such a way that the vendor does not learn σ i and the buyer does not get any information about the other messages. We ...