Cryptanalysis of Simple Substitution Ciphers Using Particle Swarm Optimization

Abstract

We investigate the use of Particle Swarm Optimization (PSO) in automated cryptanalysis of classical simple substitution ciphers. Based on our experimental results, PSO-based attacks proved to be very effective on various sets of encoding keys.

Particles Swarm Optimization for the Cryptanalysis of Transposition Cipher

“…The particles change coordinates towards gbest according to the velocity updated. If the new coordinates of the particle produce a better result than the current pbest, then the pbest is updated accordingly and compared to gbest for possible update [12]. Fig.…”

Known-ciphertext cryptanalysis approach for the Data Encryption Standard technique

“…All the dimensions are typically independent of each other, thus the updates of the velocity and the particle are performed independently in each dimension. However, in our cryptanalysis problem each solution in the parameter space represented by each particle is a permutation of the alphabetic characters corresponding to a key and hence the elements are not independent of each other [9]. The cryptanalysis using PSO involves optimal key search.…”

“…This number is obviously too large to allow any kind of exhaustive search. However, one special property of substitution cipher that makes it relatively easy to cryptanalyze, is that the language statistics remain unchanged by the encryption process and hence frequency analysis presents a basic tool for breaking classical ciphers, so that, simple substitution cipher attacked based on frequency analysis (n-gram statistics) as in [9]. And also transposition cipher attacked based on n-gram statistics in [8].…”

Cryptanalysis of Stream Cipher Cryptosystem Based on Soft Computing Techniques

“…There are many researches has been written on using soft computing techniques to cryptanalysis different types of encryption systems some of these: A.J.Clark, in his Thesis uses various optimization heuristics in the fields of automated cryptanalysis and automated cryptographic function generation [13], M.F. Uddin in his paper focused on using of PSO in cryptanalysis of simple substitution ciphers using ciphertext only attack [14],R.R.Yako In her research, an optimization approach such as GAs is considered to improve the cryptanalysis problem [15], S. M. Hameedin her work used PSO to cryptanalysis transposition cipher, PSO used ciphertext only attack to recover the secret [16],H.A.MAl_Sharifi,in his research focused on using of PSO algorithm to cryptanalysis stream cipher using plaintext attack choosing one Linear Feedback Shift Register (LFSR) [17], B.N.Ferriman, in his Thesis focused on the RC4 algorithm and present a new approach for cryptanalysis of the cipher by attacking RC4s state register [18], Ali A.Abd in his research is considered a new approach to cryptanalysis stream cipher systems based on genetic algorithm(GA) [19].The present work explores the related work done and applicability of GAs and PSOs in a field of cryptanalysis.The rest of this paper has been organized as follows: Section 2 presents a brief overview of GAs. Section 3 presents a brief overview of PSOs.…”