89 research outputs found

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

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    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

    All the King’s Men: British Codebreaking Operations: 1938-43

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    The Enigma code was one of the most dangerous and effective weapons the Germans wielded at the outbreak of the Second World War. The Enigma machine was capable of encrypting radio messages that seemed virtually unbreakable. In fact, there were 158,900, 000,000,000 possible combinations in any given message transmitted. On the eve of the war’s outbreak, the British had recently learned that the Poles had made significant progress against this intimidating cipher in the early 1930s. Incensed and with little help, the British Government Code & Cipher School began the war searching for a solution. Drawing from their experiences from the First World War, and under the visionary guidance of Alan Turing, Gordon Welchman, and countless others, the British created a new, mechanical approach to breaking the seemingly impossible German code. By breaking the code, they could very well save Britain

    Collegiate Codebreakers: Winthrop, Women, and War

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    During World War II, college-aged women from across the nation filled United States Army and Navy secretive cryptanalysis facilities to help win the war. For many women, colleges facilitated involvement in codebreaking. Through information gathered in oral histories, this thesis primarily explores war related programs at American colleges and the young women that became cryptanalysts. Academic institutions, like Winthrop College, became the nuclei for colligate codebreakers. They acted as early crypt education centers, through the offering of cryptology classes, functioned as recruitment centers, and operated as essential training hubs. While in school, young women were saturated by a climate of war and secrecy as campuses became militarized during this period. Their careers in academia and moral character came into account when cryptanalysis sectors began searching for loyal workers. While working as codebreakers for the United States government, women experienced a degree of freedom and witnessed a change in their position. In the name of the war effort and patriotic ideologies, female cryptanalysts broke codes and tested the strength of American ciphers. From college campuses to Army and Navy facilities, young women played essential roles in the war effort

    The Key to Cryptography: The RSA Algorithm

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    Cryptography is the study of codes, as well as the art of writing and solving them. It has been a growing area of study for the past 40 years. Now that most information is sent and received through the internet, people need ways to protect what they send. Some of the most commonly used cryptosystems today include a public key. Some public keys are based around using two large, random prime numbers combined together to help encrypt messages. The purpose of this project was to test the strength of the RSA cryptosystem public key. This public key is created by taking the product of two large prime numbers. We needed to find a way to factor this number and see how long it would take to factor it. So we coded several factoring algorithms to test this. The algorithms that were implemented to factor are Trial Division, Pollard’s Rho, and the Quadratic Sieve. Using these algorithms we were able to find the threshold for decrypting large prime numbers used in Cryptography

    Digital watermarking methods for data security and authentication

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    Philosophiae Doctor - PhDCryptology is the study of systems that typically originate from a consideration of the ideal circumstances under which secure information exchange is to take place. It involves the study of cryptographic and other processes that might be introduced for breaking the output of such systems - cryptanalysis. This includes the introduction of formal mathematical methods for the design of a cryptosystem and for estimating its theoretical level of securit

    Selected Topics in Cryptanalysis of Symmetric Ciphers

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    It is well established that a symmetric cipher may be described as a system of Boolean polynomials, and that the security of the cipher cannot be better than the difficulty of solving said system. Compressed Right-Hand Side (CRHS) Equations is but one way of describing a symmetric cipher in terms of Boolean polynomials. The first paper of this thesis provides a comprehensive treatment firstly of the relationship between Boolean functions in algebraic normal form, Binary Decision Diagrams and CRHS equations. Secondly, of how CRHS equations may be used to describe certain kinds of symmetric ciphers and how this model may be used to attempt a key-recovery attack. This technique is not left as a theoretical exercise, as the process have been implemented as an open-source project named CryptaPath. To ensure accessibility for researchers unfamiliar with algebraic cryptanalysis, CryptaPath can convert a reference implementation of the target cipher, as specified by a Rust trait, into the CRHS equations model automatically. CRHS equations are not limited to key-recovery attacks, and Paper II explores one such avenue of CRHS equations flexibility. Linear and differential cryptanalysis have long since established their position as two of the most important cryptanalytical attacks, and every new design since must show resistance to both. For some ciphers, like the AES, this resistance can be mathematically proven, but many others are left to heuristic arguments and computer aided proofs. This work is tedious, and most of the tools require good background knowledge of a tool/technique to transform a design to the right input format, with a notable exception in CryptaGraph. CryptaGraph is written in Rust and transforms a reference implementation into CryptaGraphs underlying data structure automatically. Paper II introduces a new way to use CRHS equations to model a symmetric cipher, this time in such a way that linear and differential trail searches are possible. In addition, a new set of operations allowing us to count the number of active S-boxes in a path is presented. Due to CRHS equations effective initial data compression, all possible trails are captured in the initial system description. As is the case with CRHS equations, the crux is the memory consumption. However, this approach also enables the graph of a CRHS equation to be pruned, allowing the memory consumption to be kept at manageable levels. Unfortunately, pruning nodes also means that we will lose valid, incomplete paths, meaning that the hulls found are probably incomplete. On the flip side, all paths, and their corresponding probabilities, found by the tool are guaranteed to be valid trails for the cipher. This theory is also implemented in an extension of CryptaPath, and the name is PathFinder. PathFinder is also able to automatically turn a reference implementation of a cipher into its CRHS equations-based model. As an additional bonus, PathFinder supports the reference implementation specifications specified by CryptaGraph, meaning that the same reference implementation can be used for both CryptaGraph and PathFinder. Paper III shifts focus onto symmetric ciphers designed to be used in conjunction with FHE schemes. Symmetric ciphers designed for this purpose are relatively new and have naturally had a strong focus on reducing the number of multiplications performed. A multiplication is considered expensive on the noise budget of the FHE scheme, while linear operations are viewed as cheap. These ciphers are all assuming that it is possible to find parameters in the various FHE schemes which allow these ciphers to work well in symbiosis with the FHE scheme. Unfortunately, this is not always possible, with the consequence that the decryption process becomes more costly than necessary. Paper III therefore proposes Fasta, a stream cipher which has its parameters and linear layer especially chosen to allow efficient implementation over the BGV scheme, particularly as implemented in the HElib library. The linear layers are drawn from a family of rotation-based linear transformations, as cyclic rotations are cheap to do in FHE schemes that allow packing of multiple plaintext elements in one FHE ciphertext. Fasta follows the same design philosophy as Rasta, and will never use the same linear layer twice under the same key. The result is a stream cipher tailor-made for fast evaluation in HElib. Fasta shows an improvement in throughput of a factor more than 7 when compared to the most efficient implementation of Rasta.Doktorgradsavhandlin

    Washington University Record, May 7, 2004

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    https://digitalcommons.wustl.edu/record/2002/thumbnail.jp

    Chiasmic Rhetoric: Alan Turing Between Bodies and Words

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    This Dissertation analyzes the life and writing of inventor and scientist Alan Turing in order to identify and theorize chiasmic relations between bodies and texts. Chiasmic rhetoric, as I develop throughout the Dissertation, is the dynamic processes between materials and discourses that interact to construct powerful rhetorical effect, shape bodies, and also compose new knowledges. My research here extends our knowledge of the rhetoric of science by demonstrating the ways that Alan Turing\u27s embodied experiences shape his rhetoric. Turing is an unusual figure for research on bodily rhetoric and embodied knowledge. He is often associated with disembodied knowledge and as his inventions are said to move intelligence towards greater abstraction and away from human bodies. However, this Dissertation exposes the many ways that bodies are active in shaping and producing knowledge even within Turing\u27s scientific and technical writing. I identify how, in every text that Turing produces, chiasmic interactions between bodies and texts actively compose Turing\u27s scientific knowledge and technical innovations towards digital computation and artificial intelligence. His knowledge, thus, is not composed out of abstract logic, or neutral technological advances. Rather, his knowledge and invention are composed and in through discourses and embodied experiences. Given that bodies and discourses are also composed within social and political power dynamics, then the political, social, and personal embodied experiences that compose Turing\u27s life and his embodiment also compose his texts, rhetoric, inventions, and science. Throughout the Dissertation, I develop chiasmic rhetoric as it develops in the rhetorical figure of chiasmus, as intersecting bodies and discourse, dynamic and productive, and potentially destabilizing. I conclude by proposing a pedagogy of care and disorientation that are attuned to the complex embodiment of students interacting with texts in our technical writing and composition classrooms
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