ENTROPY CALCULATIONS AND PARTICULAR METHODS OF CRYPTANALYSIS

ABSTRACT

Russian communications intelligence has a long history. Although originally focused on supporting the Ministry of Foreign Affairs, it subsequently expanded to include at least the Ministry of Internal Affairs as well as the Army and the Navy. Navy comint in the Baltic Sea area, in fact, was so thoroughly developed in World War I that operations undertaken by the Baltic Sea Fleet were almost always successful. A large part of the credit goes to A. I. Nepenin as chief of the Baltic Sea Fleet Communications and Intelligence Service.     

ASTLE CIPHER SOLVED

Abstract

This article describes the operation of a small U.S. Navy station in post-World War II China that primarily intercepted Soviet naval traffic as part of the worldwide BOURBON project targeting all Soviet communications systems.     

John F. Byrne's Chaocipher Revealed: An Historical and Technical Appraisal

Abstract

Chaocipher is a method of encryption invented by John F. Byrne in 1918, who tried unsuccessfully to interest the US Signal Corp and Navy in his system. In 1953, Byrne presented Chaocipher-encrypted messages as a challenge in his autobiography Silent Years. Although numerous students of cryptanalysis attempted to solve the challenge messages over the years, none succeeded. For 90 years, the Chaocipher algorithm was a closely guarded secret known only to a handful of persons. Following fruitful negotiations with the Byrne family during the period 2009–2010, the Chaocipher papers and materials have been donated to the National Cryptologic Museum in Ft. Meade, MD. This paper presents a comprehensive historical and technical evaluation of John F. Byrne and his Chaocipher system.     

Beyond human error taxonomies in assessment of risk in sociotechnical systems: a new paradigm with the EAST ‘broken-links’ approach

Abstract

Risk assessments in Sociotechnical Systems (STS) tend to be based on error taxonomies, yet the term ‘human error’ does not sit easily with STS theories and concepts. A new break-link approach was proposed as an alternative risk assessment paradigm to reveal the effect of information communication failures between agents and tasks on the entire STS. A case study of the training of a Royal Navy crew detecting a low flying Hawk (simulating a sea-skimming missile) is presented using EAST to model the Hawk-Frigate STS in terms of social, information and task networks. By breaking 19 social links and 12 task links, 137 potential risks were identified. Discoveries included revealing the effect of risk moving around the system; reducing the risks to the Hawk increased the risks to the Frigate. Future research should examine the effects of compounded information communication failures on STS performance.

Practitioner Summary: The paper presents a step-by-step walk-through of EAST to show how it can be used for risk assessment in sociotechnical systems. The ‘broken-links’ method takes a systemic, rather than taxonomic, approach to identify information communication failures in social and task networks.     

Lester Hill Revisited

Abstract

Lester Sanders Hill (1890–1961) is best known for the Hill cipher which he published in 1929. However, there seem to be four periods of Hill's career. First, in 1926 and 1927, Hill published a series of papers on mathematical error-detection. Hill's ideas for error-detection are similar to the ideas he used in his cipher. Next, in 1929 and 1931, Hill published two papers that describe the Hill cipher. The third period of Hill's career, from 1927 until 1960, was the time he served on the mathematics faculty of Hunter College. During his time at Hunter College, Hill seems to have had a relationship with the Navy in which he served during World War I. Finally, while teaching at Hunter College, in the 1950s, Hill wrote his “later papers” on cryptography, which were not published but were sent to Naval Communications.     

LADS—the Australian Laser Airborne Depth Sounder

Abstract

The Australian Laser Airborne Depth Sounder (LADS) represents a major technical transition in shallow water hydro-graphic survey that can be compared with the change from the lead line to acoustic sounder. LADS offers a substantially increased rate of data acquisition, a demonstrated accuracy which meets international hydrographic standards and a total area cover capability. The system generates discrete depth measurements in a rectangular grid pattern with 10m spacing between measurements. The concepts, methods and processing algorithms used in the design of LADS are based on an extensive research and development programme which has been widely reported in the technical literature. The LADS system has a depth capability of 50 m with depth errors less than 0.28 m (one standard deviation) over the depth range 2–30 m. LADS, installed in a Fokker F27 aircraft, is designed for operational use with the Royal Australian Navy Hydrographic Service. The project has Department of Defence approval and tenders for the manufacture and commissioning of the system are currently being sought.     

Occupational stress in submariners: The impact of isolated and confined work on psychological well-being

This study aimed to identify work-related and personal factors associated with occupational stress in submariners. Work and well-being questionnaires were distributed to 219 male submariners (mean age 34 years), as part of a larger cohort study involving a stratified sample of 4951 Royal Navy (RN) personnel. The stress rate in submariners was 40%; significantly higher than the stress rate in the general RN, although once demographic factors were controlled for in a matched control sample, this difference was no longer significant. A summary model accounted for 49% of the variance in submariner stress, with key differences emerging between the occupational factors associated with stress in submariners and in the general RN. The longitudinal nature of this study permits stress in submariners to be monitored over 5 years, which will provide valuable insights into the chronicity of stress in this specialised occupational group.

Statement of Relevance: This paper contributes to the current literature on the negative impact of working in isolated conditions. It is demonstrated that occupational stress in submarines can be partially explained using current theories of stress in the workplace. However, the constraints of a restricted environment introduce additional factors which can also be associated with occupational stress.     

An optimal H 2 decoupling design for non-square plant systems based on the two-degree-of-freedom standard model

We obtain an optimal H ₂ decoupling controller for rectangular plants in a standard two-degree-of-freedom controller configuration model. The class of all stabilizing and decoupling loop controllers is parameterized in terms of free diagonal parameter matrices. We determined the optimal decoupling controller from these free parameters. Inner-outer factorization and the Khatri-Rao product expression for the vector operation to a diagonal matrix are the key steps in obtaining the H ₂ optimal solution. We provide a compact set of assumptions to assure the existence of the optimal solution. Recommended by Editorial Board member Jietae Lee under the direction of Editor Young Il Lee. Goon-Ho Choi received the B.S. and M.S. degrees in Electrical Engineering and the Ph.D. degree in Control Engineering from Sungkyunkwan University, Suwon, Korea, on February 1993, 1995 and 1999, respectively. From 1999 to 2005, he worked as a Senior Engineer in the research and development area of Han-Mi Semiconductor Co. Ltd, Hanool Robotics Co., and Dasa Robot Co. Ltd, respectively. Since 2006, he has been a lecturer in the School of Mechanical Engineering, at Korea University of Technology and Education, Chungnam, Korea. His research interests include robust optimal control, robotics, motion control, sequence control, and the human-machine interface of an automated machine. Kiheon Park received the B.S. and M.S. degrees in Electrical Engineering from Seoul National University, Korea in 1978 and 1980, respectively, and the Ph.D. degree in System Engineering from Polytechnic University, NY, in 1987. From 1980 to 1983, he served in the Korean Navy as a Full-time Instructor at the Naval Academy. He was the recipient of a Korea Electric Association Scholarship from 1983 to 1986. From 1988 to 1990, he worked for the Electronic and Telecommunication Research Institute (ETRI), Daejeon, Korea, where he was involved in a factory automation project. Since March 1990, he has been with the School of Information and Communication Engineering at Sungkyunkwan University, Suwon, Korea, where he is currently a Professor. His research interests include linear multivariable control, decoupling controller design, vibration control and networked control systems. Joon-Hong Jung received the B.S. and M.S. degrees in Electrical Engineering from Sungkyunkwan University, Suwon, Korea, in 1996 and 1998, respectively, and the Ph.D. degree in Electrical and Computer Engineering from Sungkyunkwan University, Suwon, Korea, in 2005. From 2007 to 2008, he was a Visiting Professor at Sungkyunkwan University. Since 2005, he has been with the R&D Department at Korea Electric Power Data Network Co., Ltd., where he is currently a Staff Researcher. His research interests include network-based control system, robust control, and power system monitoring and diagnosis.     

Techniques for LAN Performance Analysis in a Real-Time Environment

The Navy is a large user of real-time systems. A modern surface ship is deployed with hundreds of computers which are required for the ship to perform its mission. The Navy is moving away from using niche market components to meet its real-time computing needs and towards distributed processing using Commercial-Off-The-Shelf (COTS) computing components. The use of commercial real-time computing components requires careful evaluation to determine if they can meet the real-time requirements. This paper focuses on evaluating the communication resources for use aboard a Navy ship. Presented are: (1) Key performance metrics for assessing the communication capabilities of computers for use aboard Navy ships; (2) An assessment of existing methods for determining these metrics; (3) A methodology for collecting data to evaluate a particular component's performance related to these; (4) Examples of applying the methodology; and (5) Examples of quantitative analysis using the metrics.     

Studies in software reengineering: Capturing navy legacy software

This report is a summary of the continuing efforts of several teams at the Naval Surface Warfare Center, Dahlgren Divsion (NSWCDD) to evaluate technologies and to define and refine a process to reengineer Navy legacy CMS-2 code into Ada. This effort involves tool and technology evaluation, methodology definition, and cost model definition.For systems developed in CMS-2, a Navy specific high order language, consideration must be given as to the most cost effective method of converting to the current high order language of choice, i.e., Ada, without losing the legacy lessons learned. NSWCDD engineers evaluated three translation tools, evaluated reverse engineering technologies, and defined both a process and a methodology to incrementally transition Navy CMS-2 code into Ada. The source code used for the evaluation is from the AEGIS Weapon System and the distributed, open environment is the High Performance Distributed Computing Program co-sponsored by the Advanced Research Projects Agency and the AEGIS Program Manager.Many of the issues identified throughout these studies are unresolved, but software engineers are continuing to evaluated the impacts of transitioning to commercial environments and Ada. Some of the issues that are being studied follow: testing of distributed systems; system level integration; lack of time-stamped instrumentation: and reliability in commercial-off-the shelf environments. The Navy is in the early stages of identifying impacts of transitioning to Ada, commercial environments, and distributed architectures. NSWCDD is gathering data to confirm that capturing legacy systems, whether it is code or design ideas, is essential to minimizing the cost and the risk of these transitions. It is also evident that technology is neither mature nor ideal yet to satisfy the identified needs for capturing the legacy of a proven system. Translation, while useful to a point, is not suitable alone as a solution to the transition equation.     

Computing the Treewidth and the Minimum Fill-In with the Modular Decomposition

Abstract. Using the notion of modular decomposition we extend the class of graphs on which both the treewidth and the minimum fill-in can be solved in polynomial time. We show that if C is a class of graphs that are modularly decomposable into graphs that have a polynomial number of minimal separators, or graphs formed by adding a matching between two cliques, then both the treewidth and the minimum fill-in on C can be solved in polynomial time. For the graphs that are modular decomposable into cycles we give algorithms that use respectively O(n) and O(n ³ ) time for treewidth and minimum fill-in.     

PP-Lowness and a Simple Definition of AWPP

Abstract. We show that the counting classes AWPP and APP [FFKL], [L] are more robust than previously thought. Our results identify a sufficient condition for a language to be low for PP, and we show that this condition is at least as weak as other previously studied criteria. We extend a result of K?bler et al. by proving that all sparse co-C ₌ P languages are in APP, and are thus PP-low. Our results also imply that AWPP ⊂eq APP, and thus APP contains many other established subclasses of PP-low, thereby reducing several different lowness results to membership in APP. We also show that AWPP and APP are Σ ⁰ ₂ -definable classes. Some of our results are reminiscent of amplifying certainty in probabilistic computation.     

Extending the cooper minimal pair theorem

In the study of cappable and noncappable properties of the recursively enumerable(r.e.)degrees.Lempp suggested a conjecture which asserts that for all r.e.degrees and b,if a ≮b then there exists an r.e.degree c such that c≤a and c≮b and c is cappable.We shall prove in this paper that this conjecture holds under the condition that a is high.Working below a high r.e.degree h,we show that for any r.e.degree b with h≮b,there exist r.e.degrees a0 and a1 and such that a0,a1≮b,a0,a1≤h,and a0 and a1 from a minimal pair.     

Model Checking Abilities of Agents: A Closer Look

Alternating-time temporal logic (atl) is a logic for reasoning about open computational systems and multi-agent systems. It is well known that atl model checking is linear in the size of the model. We point out, however, that the size of an atl model is usually exponential in the number of agents. When the size of models is defined in terms of states and agents rather than transitions, it turns out that the problem is (1) Δ ₃ ^P -complete for concurrent game structures, and (2) Δ ₂ ^P -complete for alternating transition systems. Moreover, for “Positive atl” that allows for negation only on the level of propositions, model checking is (1) Σ ₂ ^P -complete for concurrent game structures, and (2) NP-complete for alternating transition systems. We show a nondeterministic polynomial reduction from checking arbitrary alternating transition systems to checking turn-based transition systems, We also discuss the determinism assumption in alternating transition systems, and show that it can be easily removed. In the second part of the paper, we study the model checking complexity for formulae of atl with imperfect information (atl _ir ). We show that the problem is Δ ₂ ^P -complete in the number of transitions and the length of the formula (thereby closing a gap in previous work of Schobbens in Electron. Notes Theor. Comput. Sci. 85(2), 2004). Then, we take a closer look and use the same fine structure complexity measure as we did for atl with perfect information. We get the surprising result that checking formulae of atl _ir is also Δ ₃ ^P -complete in the general case, and Σ ₂ ^P -complete for “Positive atl _ir ”. Thus, model checking agents’ abilities for both perfect and imperfect information systems belongs to the same complexity class when a finer-grained analysis is used.     

The Difference between Polynomial-Time Many-One and Truth-Table Reducibilities on Distributional Problems

In this paper we separate many-one reducibility from truth-table reducibility for distributional problems in DistNP under the hypothesis that P ≠ NP . As a first example we consider the 3-Satisfiability problem (3SAT) with two different distributions on 3CNF formulas. We show that 3SAT with a version of the standard distribution is truth-table reducible but not many-one reducible to 3SAT with a less redundant distribution unless P = NP . We extend this separation result and define a distributional complexity class C with the following properties: (1) C is a subclass of DistNP, this relation is proper unless P = NP. (2) C contains DistP, but it is not contained in AveP unless DistNP \subseteq AveZPP. (3) C has a ≤ ^p _m -complete set. (4) C has a ≤ ^p _tt -complete set that is not ≤ ^p _m -complete unless P = NP. This shows that under the assumption that P ≠ NP, the two completeness notions differ on some nontrivial subclass of DistNP.     

Mr. Twinn’s bombes

This article discusses the history and design of the special versions of the bombe key-finding machines used by Britain’s Government Code & Cypher School (GC&CS) during World War II to attack the Enigma traffic of the Abwehr (the German military intelligence service). These special bombes were based on the design of their more numerous counterparts used against the traffic of the German armed services, but differed from them in important ways that highlight the adaptability of the British bombe design, and the power and flexibility of the diagonal board. Also discussed are the changes in the Abwehr indicating system that drove the development of these machines, the ingenious ways in which they were used, and some related developments involving the bombes used by the U.S. Navy’s cryptanalytic unit (OP-20-G).     

Local noncuppability in R/M

Given any [c],[a],[d]∈R/M such that [d]≤[a]≤[c], [a] is locally noncuppable between [c] and [d] if [d]<[a]≤[c]and [a] ∨ [b] < [c] for any [b]∈R/M such that [d]≤ [ b ] < [ c ]. It will be shown that given any nonzero [ c ] ∈ R/M, there are [ a ], [ d ] ∈R/M such that [d]<[a]≤[c] and[a] is locally noncuppable between [c] and[d].     

Considerations for automatic testing of complex shipboard systems

An approach for automatically testing complex shipboard systems is developed. After first considering the general system requirements of such a system, the paper considers the advantages and disadvantages associated with automatic testing. Based on these tradeoffs, a technique is developed for automatically testing large complex systems such as that found aboard a ship. The concept considers both hardware and software requirements which will minimize uncertainties associated with automatic testing. The paper concludes with an example of a recent Navy development in the area of centralized shipboard, general-purpose, on-line systems for monitoring and fault isolation—the Test Evaluation and Monitoring System (TEAMS).