How to distinguish between a block cipher and a random permutation by lowering the input entropy

IEEE 35th International Carnahan Conference on Security Technology. Londres, 16-19 October 2001A novel cryptanalysis technique is presented, and its suitability for distinguishing a block cipher algorithm or a hash function from a random permutation is explained. Additionally, we propose a genetic algorithm based implementation and show some preliminary results of these ideas on reduced rounds versions of the block cipher TEA

Encryption Efficiency Analysis and Security Evaluation of RC6 Block Cipher for Digital Images

This paper investigates the encryption efficiency of RC6 block cipher application to digital images, providing a new mathematical measure for encryption efficiency, which we will call the encryption quality instead of visual inspection, The encryption quality of RC6 block cipher is investigated among its several design parameters such as word size, number of rounds, and secret key length and the optimal choices for the best values of such design parameters are given. Also, the security analysis of RC6 block cipher for digital images is investigated from strict cryptographic viewpoint. The security estimations of RC6 block cipher for digital images against brute-force, statistical, and differential attacks are explored. Experiments are made to test the security of RC6 block cipher for digital images against all aforementioned types of attacks. Experiments and results verify and prove that RC6 block cipher is highly secure for real-time image encryption from cryptographic viewpoint. Thorough experimental tests are carried out with detailed analysis, demonstrating the high security of RC6 block cipher algorithm. So, RC6 block cipher can be considered to be a real-time secure symmetric encryption for digital images

A General Analysis of the Security of Elastic Block Ciphers

We analyze the security of elastic block ciphers in general to show that an attack on an elastic version of block cipher implies a polynomial time related attack on the fixed-length version of the block cipher. We relate the security of the elastic version of a block cipher to the fixed-length version by forming a reduction between the versions. Our method is independent of the specific block cipher used. The results imply that if the fixed-length version of a block cipher is secure against attacks which attempt key recovery then the elastic version is also secure against such attacks

A New 128-Bit Block Cipher

The evolvement of technology have resulted in a number of new proposals done on block ciphers such as KAMFEE, KAMKAR, ARIA, BLOWFISH256, DESL, REBC2, DSDP and etc. Even though there have been so much development of the block cipher, the industry still requires another block cipher as long as security features are met. Every country has different requirements when requesting block cipher so there is no limit in developing them. According to the National IT Council (NlTC) report on "Securing Malaysia Sovereignty in the CyberWorld" provided by Ministry of Science, Technology and Innovation, Malaysia, they have outlined critical areas in which new and additional research and development is needed to increase the protection of the national information infrastructure. One of the critical areas is, secured communication which helps to protect the confidentiality and integrity of information during transmission and storage. Secured communication can be achieved by encrypting and hiding data transmission when it is stored on a system. One of the areas which have been identified as priority with respect to secured communications is, conventional cryptography which provides the fundamental security and privacy in the information society. Towards that and after reviewing related research, in this research we propose to come up with a new 128-bit block cipher cryptographic algorithm which shall meet the security requirements. This block cipher uses 128-bit for the key length and block size. It is an involution substitution and permutation encryption network (SPN). This block cipher uses only basic operations, key dependent S-box and XOR IS together so that it can be efficiently implemented on various platforms. The strength of this system is measured by NIST Statistical Test which evaluate from the point of view of the randomness of the block cipher output. From the results, this new block cipher has successfully generated randomness of the block cipher output for data ranging from 1 ,000,000 to 6,000,000 bits. This means that the new block cipher is secured to be used for data ranging from 1 ,000,000 to 6,000,000 bits. This block cipher is suitable to be applied to small devices such as mobile phones and PDAs. The existence of this new 128-bit block cipher algorithm will increase the protection of the national information infrastructure and also will contribute as an alternative to other cryptographic algorithms in security in the computing industry

Key classification attack on block ciphers

In this paper, security analysis of block ciphers with key length greater than block length is proposed. When key length is significantly greater than block length and the statistical distribution of cipher system is like a uniform distribution, there are more than one key which map fixed input to fixed output. If a block cipher designed sufficiently random, it is expected that the key space can be classified into same classes. Using such classes of keys, our proposed algorithm would be able to recover the key of block cipher with complexity O(max(2^n, 2^{k-n}) where n is block length and k is key length. We applied our algorithm to 2- round KASUMI block cipher as sample block cipher by using weakness of functions that used in KASUMI

Implementasi Uji Korelasi untuk Pengujian Sub Kunci pada Algoritma Kriptografi Block Cipher Present Menggunakan Bahasa Pemrograman C++

Kriptografi merupakan salah satu teknik dalam mengamankan suatu informasi berklasifikasi. Penerapan suatu aplikasi kriptografi dalam mengamankan suatu informasi tidak lepas dari pemilihan kekuatan algoritma kriptografi yang digunakan. Pada algoritma kriptografi block cipher, salah satu komponen pembangun yang harus diperhatikan adalah key schedule, untuk menghasilkan sub kunci yang digunakan pada proses enkripsi/dekripsi. Metode uji korelasi merupakan salah satu metode yang digunakan untuk menguji kekuatan algoritma kriptografi block cipher. Penelitian paper ini akan membuat implementasi pengujian korelasi menggunakan bahasa pemrograman C++, yang dterapkan pada block cipher PRESENT sebagai salah satu algoritma yang banyak digunakan saat ini