A New Type of Cipher: DICING_csb

In this paper, we will propose a new type of cipher named DICING_csb, which is derived from our previous stream cipher DICING. It has applied a stream of subkey and an encryption form of block ciphers, so it may be viewed as a combinative of stream cipher and block cipher. Hence, the new type of cipher has fast rate like a stream cipher and need no MAC.Comment: There is a new variant added in the section

Stream cipher based on quasigroup string transformations in Zp∗Z_p^*

In this paper we design a stream cipher that uses the algebraic structure of the multiplicative group \bbbz_p^* (where p is a big prime number used in ElGamal algorithm), by defining a quasigroup of order $p-1$ and by doing quasigroup string transformations. The cryptographical strength of the proposed stream cipher is based on the fact that breaking it would be at least as hard as solving systems of multivariate polynomial equations modulo big prime number $p$ which is NP-hard problem and there are no known fast randomized or deterministic algorithms for solving it. Unlikely the speed of known ciphers that work in \bbbz_p^* for big prime numbers $p$, the speed of this stream cipher both in encryption and decryption phase is comparable with the fastest symmetric-key stream ciphers.Comment: Small revisions and added reference

Comparison analysis of stream cipher algorithms for digital communication

The broadcast nature of radio communication such as in the HF (High Frequency) spectrum exposes the transmitted information to unauthorized third parties. Confidentiality is ensured by employing cipher system. For bulk transmission of data, stream ciphers are ideal choices over block ciphers due to faster implementation speed and not introducing error propagation. The stream cipher algorithms evaluated are based on the linear feedback shift register (LFSR) with nonlinear combining function. By using a common key length and worst case conditions, the strength of several stream cipher algorithms are evaluated using statistical tests, correlation attack, linear complexity profile and nonstandard test. The best algorithm is the one that exceeds all of the tests

SUATU ALGORITMA KRIPTOGRAFI STREAM CIPHER BERDASARKAN FUNGSI CHAOS

Salah satu sifat fungsi chaos adalah sensitif terhadap nilai awal, artinya perubahan kecil pada nilai awal akan mengakibatkan perubahan besar pada nilai fungsi selanjutnya. Sifat seperti ini dapat diterapkan dalam kriptografi, terutama dalam algoritma kriptografi stream cipher. Pada stream cipher digunakan sebuah kunci yang disebut dengan kunci awal, dari kunci ini dibuat kunci yang lebih panjang dari kunci awal yang disebut dengan key stream. Penerapan fungsi chaos dalam stream cipher tentu menguntungkan, karena sifat sensitif pada nilai awal tersebut, sehingga diharapkan dapat meningkatkan keamanan dari stream cipher yang didasarkan pada fungsi chaos. Kata kunci: enkripsi simetris, fungsi chaos, pembangkitan kunci rahasi