Simon and Speck are two families of ultra-lightweight block ciphers which were announced by the U.S. National Security Agency in June 2013. Yet, the specification discusses only the design and the performance of both cipher families and the task of analyzing their security has been left to the were proposed by the U.S. National Security Agency in June 2013. Yet, the specification paper discusse...

We propose a new 128-bit blockcipher CLEFIA supporting key lengths of 128, 192 and 256 bits, which is compatible with AES. CLEFIA achieves enough immunity against known attacks and flexibility for efficient implementation in both hardware and software by adopting several novel and state-of-the-art design techniques. CLEFIA achieves a good performance profile both in hardware and software. In ha...

Statement 1. HC-128 supports 128-bit key and 128-bit initialization vector. Statement 2. 2 keystream bits can be generated from each key/IV pair. Statement 3. There is no hidden flaw in HC-128. Statement 4. The smallest period is expected to be much larger than 2. Statement 5. Recovering the secret key is as difficult as exhaustive key search. Statement 6. Distinguishing attack requires more th...

Th e conceptual framework of ecostrategies (views and use of landscape) presented here have been used to analyse various cases of nature-based tourism and related activities such as outdoor recreation, outdoor education, nature reserves and conservation. Th e role of the ecostrategies is to illustrate the intersections, confl icts and alliances between diff erent types of nature based tourism a...

This paper presents two attacks against Achterbahn-128/80, the last version of one of the stream cipher proposals in the eSTREAM project. The attack against the 80-bit variant, Achterbahn-80, has complexity 2^{56.32}. The attack against Achterbahn-128 requires 2^{75.4} operations and 2^{61} keystream bits. These attacks are based on an improvement of the attack due to Hell and Johansson against...

HC-128 is an eSTREAM final portfolio stream cipher. Several authors have investigated its security and, in particular, distinguishing attacks have been considered. Still, no one has been able to provide a distinguisher stronger than the one presented by Wu in the original HC128 paper. In this paper we first argue that the keystream requirement in Wu’s original attack is underestimated by a fact...

This paper presents two key-recovery attacks against Achterbahn-128/80, the last version of one of the stream cipher proposals in the eSTREAM project. The attack against the 80-bit variant, Achterbahn80, has complexity 2. The attack against Achterbahn-128 requires 2 operations and 2 keystream bits. These attacks are based on an improvement of the attack due to Hell and Johansson against Achterb...