A dynamical systems approach to the discrimination of the modes of operation of cryptographic systems

Evidence of signatures associated with cryptographic modes of operation is established. Motivated by some analogies between cryptographic and dynamical systems, in particular with chaos theory, we propose an algorithm based on Lyapunov exponents of discrete dynamical systems to estimate the divergence among ciphertexts as the encryption algorithm is applied iteratively. The results allow to distinguish among six modes of operation, namely ECB, CBC, OFB, CFB, CTR and PCBC using DES, IDEA, TEA and XTEA block ciphers of 64 bits, as well as AES, RC6, Twofish, Seed, Serpent and Camellia block ciphers of 128 bits. Furthermore, the proposed methodology enables a classification of modes of operation of cryptographic systems according to their strength.Comment: 14 pages, 10 figure

Machine Learning for Offensive Cyber Operations

In pape

CRYPTSIM: SIMULATORS FOR CLASSIC ROTOR CIPHERS

In this project, web-based visual simulators have been implemented for three classic rotor cipher machines: Enigma, Typex, and Sigaba. Enigma was used by Germany during World War II, while Typex is a British cipher that was based on the commercial version of the Enigma. Sigaba is a relatively complex machine that was used by the Americans during the 1940s and into the 1950s. Sigaba is the most secure of the three ciphers, there was no successful attack on Sigaba during its service lifetime. Our web-based visual simulators are functionally equivalent to the actual electro- mechanical machines. Each simulator allows the user to initialize the key and encrypt or decrypt. Also, each simulator provides a web-based “play station” that allows the user to understand how these classic ciphers work by observing their internal operations when encrypting and decrypting. These simulators do not require any installation, and users can access the simulators provided they have access to the Internet

Multi-algorithmic Cryptography using Deterministic Chaos with Applications to Mobile Communications

In this extended paper, we present an overview of the principal issues associated with cryptography, providing historically significant examples for illustrative purposes as part of a short tutorial for readers that are not familiar with the subject matter. This is used to introduce the role that nonlinear dynamics and chaos play in the design of encryption engines which utilize different types of Iteration Function Systems (IFS). The design of such encryption engines requires that they conform to the principles associated with diffusion and confusion for generating ciphers that are of a maximum entropy type. For this reason, the role of confusion and diffusion in cryptography is discussed giving a design guide to the construction of ciphers that are based on the use of IFS. We then present the background and operating framework associated with a new product - CrypsticTM - which is based on the application of multi-algorithmic IFS to design encryption engines mounted on a USB memory stick using both disinformation and obfuscation to ‘hide’ a forensically inert application. The protocols and procedures associated with the use of this product are also briefly discussed

A Covert Encryption Method for Applications in Electronic Data Interchange

A principal weakness of all encryption systems is that the output data can be ‘seen’ to be encrypted. In other words, encrypted data provides a ‘flag’ on the potential value of the information that has been encrypted. In this paper, we provide a new approach to ‘hiding’ encrypted data in a digital image. In conventional (symmetric) encryption, the plaintext is usually represented as a binary stream and encrypted using an XOR type operation with a binary cipher. The algorithm used is ideally designed to: (i) generate a maximum entropy cipher so that there is no bias with regard to any bit; (ii) maximize diffusion in terms of key dependency so that a change in any bit of the key can effect any, and potentially all, bits of the cipher. In the work reported here, we consider an approach in which a binary or low-bit plaintext image is encrypted with a decimal integer or floating point cipher using a convolution operation and the output quantized into a 1-bit array generating a binary image ciphertext. This output is then ‘embedded’ in a host image to hide the encrypted information. Embedding is undertaken either in the lowest 1-bit layer or multiple 1-bit layers. Decryption is accomplished by: (i) extracting the binary image from the host image; (ii) correlating the result with the original cipher. In principle, any cipher generator can be used for this purpose and the method has been designed to operate with 24-bit colour images. The approach has a variety of applications and, in this paper, we focus on the authentication and self-authentication of e-documents (letters and certificates, for example) that are communicated over the Internet and are thereby vulnerable to attack (e.g. modification, editing, counterfeiting etc.). In addition to document authentication, the approach considered provides a way of propagating disinformation and a solution to scenarios that require ‘plausible deniability’

Re-engineering the Enigma cipher.

The design of this thesis is to re-engineer the Enigma cipher to make it a viable, secure cipher for use on current computers. The goal is to create a cipher based on an antiquated mechanical cryptography device, the Enigma Machine, in software and improve upon it. The basic principle that is being expounded upon here is that while the Enigma cipher\u27s security was originally very dependent on security through obscurity, this needs to be secure on its own. Also, this must be a viable solution for the encryption of data based on modern standards. The Enigma Phoenix, the name for this new cipher, will use Galois functions and other modern improvements to add an extra level of security to it and to make it the viable solution that is desired