The Conservation Status of the Pyramid of Khufu

The biggest Pyramid in Giza, the Pyramid of Khufu, one of the most lasting monuments ever achieved, is losing substance through mutilation, pillage and destruction, along with the degrading effects of wind, rain, and sun. Also, the daily flow of 6,000 visitors to the Pyramid of Khufu produce water vapor, carbon dioxide, and heat that forms condensation on the inner walls which become salt deposits that damage those walls.The Tura limestone coatings of the Pyramid of Khufu have been removed over time to build the city of Cairo. This pilferage lasted for centuries and left the Great Pyramid with few traces of its white limestone coating.Changing the environment of the Giza Plateau to green vegetation would shield the Great Pyramids, affected by the deterioration factors related to weather and the arid climate of the Sahara desert. This environmental intervention returns the plateau to its original arrangement of ancient Egypt, when it had canal systems and cisterns for conserving water for domestic and agricultural use. These canals should be found and renovated and made operative. Removal of the fence surrounding the archaeological site to create an (archaeological basin) would reinstate the once pleasant mingling of tourists and locals. Keywords: Egypt, Giza, Desert, Limestone, Deterioration, Environment

Improved cryptanalysis of skein

The hash function Skein is the submission of Ferguson et al. to the NIST Hash Competition, and is arguably a serious candidate for selection as SHA-3. This paper presents the rst third-party analysis of Skein, with an extensive study of its main component: the block cipher Three sh. We notably investigate near collisions, distinguishers, impossible di erentials, key recovery using related-key di erential and boomerang attacks. In particular, we present near collisions on up to 17 rounds, an impossible di erential on 21 rounds, a related-key boomerang distinguisher on 34 rounds, a known-related-key boomerang distinguisher on 35 rounds, and key recovery attacks on up to 32 rounds, out of 72 in total for Threefish-512. None of our attacks directly extends to the full Skein hash. However, the pseudorandomness of Threefish is required to validate the security proofs on Skein, and our results conclude that at least 3

An overview of memristive cryptography

Smaller, smarter and faster edge devices in the Internet of things era demands secure data analysis and transmission under resource constraints of hardware architecture. Lightweight cryptography on edge hardware is an emerging topic that is essential to ensure data security in near-sensor computing systems such as mobiles, drones, smart cameras, and wearables. In this article, the current state of memristive cryptography is placed in the context of lightweight hardware cryptography. The paper provides a brief overview of the traditional hardware lightweight cryptography and cryptanalysis approaches. The contrast for memristive cryptography with respect to traditional approaches is evident through this article, and need to develop a more concrete approach to developing memristive cryptanalysis to test memristive cryptographic approaches is highlighted.Comment: European Physical Journal: Special Topics, Special Issue on "Memristor-based systems: Nonlinearity, dynamics and applicatio

Down the Rabbit Hole: Revisiting the Shrinking Method

The paper is about methodology to detect and demonstrate impossible differentials in a block cipher. We were inspired by the shrinking technique proposed by Biham et al. in 1999 which recovered properties of scalable block cipher structures from numerical search on scaled down variants. Attempt to bind all concepts and techniques of impossible differentials together reveals a view of the search for impossible differentials that can benefit from the computational power of a computer. We demonstrate on generalized Feistel networks with internal permutations an additional clustering layer on top of shrinking which let us merge numerical data into relevant human-readable information to be used in an actual proof. After that, we show how initial analysis of scaled down TEA-like schemes leaks the relevant part of the design and the length and ends of the impossible differentials. We use that initial profiling to numerically discover 4 15-round impossible differentials (beating the current 13-round) and thousands of shorter ones

KronCrypt - A New Symmetric Cryptosystem Based on Kronecker\u27s Approximation Theorem

In this paper we show how to use an old mathematical concept of diophantine analysis, the approximation theorem of Kronecker, in symmetric cryptography. As a first practical application we propose and analyze the new symmetric 128-bit block cipher KronCrypt. The cipher is a 4-round Feistel network with a non-bijective round function f made up of a variable number of large key-dependent S-boxes, XORs and modular additions. Its key length is variable but not less than 128 bit. The main innovation of KronCrypt in the area of symmetric cryptography is the fact that the key-dependent S-boxes are based upon a constructive proof of the approximation theorem of Kronecker used as a boolean function. We prove the correctness of our concept in general and show how we designe the new cipher KronCrypt. Furthermore, results concerning statistical behaviour, i.e. confusion, diffusion and completeness, and differential cryptanalysis are presented

A new meet-in-the-middle attack on the IDEA block cipher

In this paper we introduce a novel meet-in-the-middle attack on the IDEA block cipher. The attack consists of a precomputation and an elimination phase. The attack reduces the number of required plaintexts significantly for 4 and 4.5 rounds, and, to the best of our knowledge, it is the first attack on the 5-round IDEA. © Springer-Verlag Berlin Heidelberg 2004

Improved Cryptanalysis of Skein

The hash function Skein is the submission of Ferguson et al. to the NIST Hash Competition, and is arguably a serious candidate for selection as SHA-3. This paper presents the rst third-party analysis of Skein, with an extensive study of its main component: the block cipher Three sh. We notably investigate near collisions, distinguishers, impossible di erentials, key recovery using related-key di erential and boomerang attacks. In particular, we present near collisions on up to 17 rounds, an impossible di erential on 21 rounds, a related-key boomerang distinguisher on 34 rounds, a known-related-key boomerang distinguisher on 35 rounds, and key recovery attacks on up to 32 rounds, out of 72 in total for Threefish-512. None of our attacks directly extends to the full Skein hash. However, the pseudorandomness of Threefish is required to validate the security proofs on Skein, and our results conclude that at least 3