A grammar of Nias Selatan

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Computational and Algebraic Aspects of the Advanced Encryption Standard

Abstract. The new Advanced Encryption Standard (AES) has been recently selected by the US government to replace the old Data Encryption Standard (DES) for protecting sensitive official information. Due to its simplicity and elegant algebraic structure, the choice of the AES algorithm has motivated the study of a new approach to the analysis of block ciphers. While conventional methods of cryptanalysis (e.g. differential and linear cryptanalysis) are usually based on a “statistical ” approach, where an attacker attempts to construct statistical patterns through many interactions of the cipher, the so-called algebraic attacks exploit the intrinsic algebraic structure of a cipher. More specifically, the attacker expresses the encryption transformation as a set of multivariate polynomial equations and attempts to recover the encryption key by solving the system. In this paper we consider a number of algebraic aspects of the AES, and examine a few computational and algebraic techniques that could be used in the cryptanalysis of cipher. We show how one can express the cipher as a very large, though surprisingly simple, system of multivariate quadratic equations over the finite field F 2 8, and consider some approaches that can be used to solve this system

The LED Block Cipher

Abstract. We present a new block cipher LED. While dedicated to compact hardware implementation, and offering the smallest silicon footprint among comparable block ciphers, the cipher has been designed to simultaneously tackle three additional goals. First, we explore the role of an ultra-light (in fact non-existent) key schedule. Second, we consider the resistance of ciphers, and LED in particular, to related-key attacks: we are able to derive simple yet interesting AES-like security proofs for LED regarding related- or single-key attacks. And third, while we provide a block cipher that is very compact in hardware, we aim to maintain a reasonable performance profile for software implementation. Key words: lightweight, block cipher, RFID tag, AES.

LBlock: a lightweight block cipher

In this paper, we propose a new lightweight block cipher called LBlock. Similar to many other lightweight block ciphers, the block size of LBlock is 64-bit and the key size is 80-bit. Our security evaluation shows that LBlock can achieve enough security margin against known attacks, such as differential cryptanalysis, linear cryptanalysis, impossible differential cryptanalysis and related-key attacks etc. Furthermore, LBlock can be implemented efficiently not only in hardware environments but also in software platforms such as 8-bit microcontroller. Our hardware implementation of LBlock requires about 1320 GE on 0.18 µm technology with a throughput of 200 Kbps at 100 KHz. The software implementation of LBlock on 8-bit microcontroller requires about 395