In mobile ad hoc networks, the absence ofinfrastructure and the consequent absence of authorizationfacilities impede the usual practice of establishing a practicalcriterion to distinguishing nodes as trusted and distrusted.Since all nodes in the MANETs would be used as router inmulti-hop applications, secure routing protocols have vital rulein the security of the network. So evaluating the perf...

Hash functions are often constructed based on permutations or blockciphers, and security proofs are typically done in the ideal permutation or cipher model. However, once these random primitives are instantiated, vulnerabilities of these instantiations may nullify the security. At ASIACRYPT 2007, Knudsen and Rijmen introduced known-key security of blockciphers, which gave rise to many distingui...

Feistel constructions have been shown to be indifferentiable from random permutations at STOC 2011. Whereas how to properly mix the keys into an un-keyed Feistel construction without appealing to domain separation technique to obtain a block cipher which is provably secure against known-key and chosen-key attacks (or to obtain an ideal cipher) remains an open problem. We study this, particularl...

The stream ciphers Py, Py6 were designed by Biham and Seberry for the ECRYPT-eSTREAM project in 2005. However, due to several recent cryptanalytic attacks on them, a strengthened version Pypy was proposed to rule out those attacks. The ciphers have been promoted to the ‘Focus’ ciphers of the Phase II of the eSTREAM project. The impressive speed of the ciphers make them the forerunners in the co...

Knudsen and Rijmen introduced the notion of known-key distinguishers in an effort to view block cipher security from an alternative perspective e.g. a block cipher viewed as a primitive underlying some other cryptographic construction such as a hash function; and applied this new concept to construct a 7-round distinguisher for the AES and a 7-round Feistel cipher. In this paper, we give a natu...

McGrew and Fluhrer first proposed hash-counter-hash approach to encrypt arbitrary length messages. By its nature, counter can handle incomplete message blocks as well as complete message blocks in the same manner. HCTR is the till date best (in terms of efficiency) strong pseudo random permutation or SPRP among all known counter based SPRPs. But as of now, a cubic bound for HCTR is known. Moreo...

In this paper we address an open key issue during the development of web-based educational systems. In particular, we provide an educational-oriented approach for building personalised e-learning environments that focuses on putting the learners’ needs in the centre of the development process. Our approach proposes user centred design methodologies involving interdisciplinary teams of software ...

In this paper, we propose a novel technique, called multi-output filtering model, to study the non-randomness property of a cryptographic algorithm such as message authentication codes and block ciphers. A multi-output filtering model consists of a linear feedback shift register (LFSR) and a multi-output filtering function. Our contribution in this paper is twofold. First, we propose an attack ...

We present a neural network based approach to key frame extraction in the compressed domain. The proposed method is an amalgamation of both the MPEG-7 descriptors namely motion intensity descriptor and spatial activity descriptor. Shot boundary detection and block motion estimation techniques are employed prior to the extraction of the descriptors. The motion intensity (“pace of action”) is obt...

At EUROCRYPT 2012 Pandey and Rouselakis introduced the notion of property preserving symmetric encryption which enables checking for a property on plaintexts by running a public test on the corresponding ciphertexts. Their primary contributions are: (i) a separation between ‘find-then-guess’ and ‘left-or-right’ security notions; (ii) a concrete construction for left-or-right secure orthogonalit...