Conventional class of weak keys on RC4 stream cipher is defined as a specific case that combinations of the first three bytes of secret key satisfy two relational equations. This paper expands and generalizes the classes of weak keys using generalized relational equations and special classes of the internal state (called predictive state). We derive the probability that generalized classes of w...

In this very short note we prove that the pseudo-random index j of RC4 is indeed not pseudo-random. This is a simple result that missed our attention for quite a long time. We show that in long term Pr(j = i + 1) = 1 N − 1 N2 , instead of the random association 1 N and this happens for the non-existence of the condition S[i] = 1 and j = i + 1 that is mandatory for the non-existence of the Finne...

Pada zaman digital saat ini, memberikan keamanan dan kerahasiaan informasi sangat penting ketika melakukan pertukaran melalui jaringan komunikasi. Hal ini bertujuan agar yang dikirimkan oleh pengirim dapat diterima secara utuh penerima tanpa adanya campur tangan pihak ketiga tidak berhak atas tersebut. Kriptografi Steganografi merupakan teknik digunakan untuk mengamankan sebuah pesan rahasia, s...

This paper investigates the practical security of RC4 in broadcast setting where the same plaintext is encrypted with different user keys. We introduce several new biases in the initial (1st to 257th) bytes of the RC4 keystream, which are substantially stronger than known biases. Combining the new biases with the known ones, a cumulative list of strong biases in the first 257 bytes of the RC4 k...

This study presents a design methodology for Takagi-Sugeno (T-S) fuzzy models-based secure communications in multiple time-delay chaotic (MTDC) systems with Rivest cipher 4 (RC4) algorithm. The main advantage of the RC4 algorithm is that key length does not affect encryption and decryption speeds. To block hacker from stealing message, this proposes increasing complexity an encrypted message (c...