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The author's considerations try to answer three questions, viz. (1) whether the cryptogram written on the copy of the Penticostal Triod (Cracovia, 1491), treasured at Şcheii Braşovului church, belongs to the Greek key system, (2) the complete de-ciphering of the cryptogram in the Romanian manuscript 3278 (Romanian Academy Library), and (3) the publication of the Slavic version of the Praise to the Worthy Cross from the Romanian manuscript 5023 (Romanian Academy Librabry) and the explanations supplied to various cryptograms of the cross found in the Slavic manuscript 13 and the Slavic manuscript 494 (Romanian Academy Library). [ABSTRACT FROM AUTHOR]

n this paper, an analysis system currently existing steganographic methods for improving the stability of different types of attacks, which can be subjected to steganographic container in a channel of information transfer. An offender stegosystem systematization model and, according to this, a classification of types of attacks. As a result, given the most effective methods to protect steganographic data, and general guidelines for their use. [ABSTRACT FROM AUTHOR]

It has been substantiated that the personal means of cryptographic information security SHIPKA prone to timing attacks. Algorithms used in RSA cryptosystem, such as Simple Modular Exponentiation, Montgomery reduction, Chinese Remainder Theorem, have been considered. It has been reported how timing attacks can be performed. Blinding has been suggested to be used in SHIPKA as countermeasures to prevent timing attacks on RSA. [ABSTRACT FROM AUTHOR]

In this article the structure of elliptic cryptography, its shape and main points of application is reviewed.We examined advantages of using ECC comparing with RSA and others. Main dates about this branch of cryptography is described. We put together information about patents, relating to this theme. Also in this article the question about if we should trust to NIST recommended curves is bumbed. As the conclusion we give comparing table ECC and RSA. Thoughts that Elliptic curves will be successful as to their key length, less demanding performance, security. Elliptic Curves are used to pass data through TLS, SSH, also used in smart-cards, Bitcoin, C++, Apple's i Message service. Now the steering committee is actively engaged on ECC in the head of Tanja Lange (Technische Universiteit Eindhoven, Netherlands), Chair Alfred Menezes (University of Waterloo, Canada), Christof Paar (Ruhr-Universität Bochum, Germany), Scott Vanstone (University of Waterloo, Canada). ECC is an annual workshops dedicated to the study of elliptic curve cryptography and related areas. Since the first ECC workshop, held 1997 in Waterloo, the ECC conference series has broadened its scope beyond elliptic curve cryptography and now covers a wide range of areas within modern cryptography. [ABSTRACT FROM AUTHOR]

This paper presents a method to detect video tampering and distinguish it from common video processing operations, such as recompression, noise, and brightness increase, using a practical watermarking scheme for real-time authentication of digital video. In our method, the watermark signals represent the macroblock's and frame's indices, and are embedded into the nonzero quantized discrete cosine transform value of blocks, mostly the last nonzero values, enabling our method to detect spatial, temporal, and spatiotemporal tampering. Our method can be easily configured to adjust transparency, robustness, and capacity of the system according to the specific application at hand. In addition, our method takes advantage of content-based cryptography and increases the security of the system. While our method can be applied to any modern video codec, including the recently released high-efficiency video coding standard, we have implemented and evaluated it using the H.264/AVC codec, and we have shown that compared with the existing similar methods, which also embed extra bits inside video frames, our method causes significantly smaller video distortion, leading to a PSNR degradation of about 0.88 dB and structural similarity index decrease of 0.0090 with only 0.05% increase in bitrate, and with the bit correct rate of 0.71 to 0.88 after H.264/AVC recompression. [ABSTRACT FROM PUBLISHER]

The article discusses basic principles of network steganography, which is a comparatively new research subject in the area of information hiding, followed by a concise overview and classification of network steganographic methods and techniques. [ABSTRACT FROM PUBLISHER]

Network security consists of the provisions and policies adopted by a network administrator to prevent and monitor unauthorized access, misuse, modification, or denial of a computer network and network-accessible resources. Network security involves the authorization of access to data in a network, which is controlled by the network administrator. Users choose or are assigned an ID and password or other authenticating information that allows them access to information and programs within their authority. Network security covers a variety of computer networks, both public and private, that are used in everyday jobs conducting transactions and communications among businesses, government agencies and individuals. Networks can be private, such as within a company, and others which might be open to public access. Network security is involved in organizations, enterprises, and other types of institutions. It does as its title explains: It secures the network, as well as protecting and overseeing operations being done. The most common and simple way of protecting a network resource is by assigning it a unique name and a corresponding password Network security has become more important to personal computer users, organizations, and the military. With all the work going on the internet, Security became a major concern and the history of security allows a better understanding of the emergence of security technology. The range of study includes a brief history dating back to internet's beginnings and the current development in network security. In order to understand their search being performed today, background knowledge of the internet, its vulnerabilities, attack methods through the internet, and security technology is important and therefore they are reviewed. [ABSTRACT FROM AUTHOR]

Side channel attacks allow an attacker to retrieve secret keys with far less effort than other attacks. Countermeasures against these attacks should be considered during cryptosystem design. This paper presents a novel low-cost error detection and recovery scheme (LOEDAR) to counter fault attacks. The proposed architecture retains the efficiency of the Montgomery ladder algorithm and shows strong resistance to both environmental-induced faults as well as attacker-introduced faults. Moreover, the proposed LOEDAR scheme is compatible with most existing countermeasures against various power analysis attacks including differential power analysis and its variants, which makes it extendable to a comprehensive countermeasure against both fault attacks and power analysis attacks. [ABSTRACT FROM PUBLISHER]

In the problem of secure message transmission in the public discussion model (SMT-PD), a sender wants to send a message M{\cal S}\in\{0,1\}^{\ell} to a receiver privately and reliably. Sender and receiver are connected by n channels, also known as simple wires, up to t

This paper investigates the power of SAT solvers in cryptanalysis. The contributions are two-fold and are relevant to both theory and practice. First, we introduce an efficient, generic and automated method for generating SAT instances encoding a wide range of cryptographic computations. This method can be used to automate the first step of algebraic attacks, i.e. the generation of a system of algebraic equations. Second, we illustrate the limits of SAT solvers when attacking cryptographic algorithms, with the aim of finding weak keys in block ciphers and preimages in hash functions. SAT solvers allowed us to find, or prove the absence of, weak-key classes under both differential and linear attacks of full-round block ciphers based on the International Data Encryption Algorithm (IDEA), namely, WIDEA-n for n ∈ {4, 8}, and MESH-64(8). In summary: (i) we have found several classes of weak keys for WIDEA-n and (ii) proved that a particular class of weak keys does not exist in MESH-64(8). SAT solvers provided answers to two complementary open problems (presented in Fast Software Encryption 2009): the existence and non-existence of such weak keys. Although these problems were supposed to be difficult to answer, SAT solvers provided an efficient solution. We also report on experimental results about the performance of a modern SAT solver as the encoded cryptanalytic tasks become increasingly hard. The tasks correspond to preimage attacks on reduced MD4 algorithm. [ABSTRACT FROM AUTHOR]

Recently, Liu et al. have proved a class of 2k-variable Boolean functions to have optimal algebraic immunity and good immunity to fast algebraic attacks. In this paper, we proceed to study those functions in aspect of correlation immunity and nonlinearity and through restrictions to those functions we propose two sub-classes of 2k-variable Boolean functions with good cryptographic properties. To the best of our knowledge, this is the first time whole classes of Boolean functions with high nonlinearity, 1-correlation immunity and good immunity against FAA can be found. [ABSTRACT FROM AUTHOR]

In the paper the analysis of regulatory and legislative capacity on state secrets security as part of the national security of Ukraine against real and potential threats in the information sphere. Detailed considered regulating the content and definition of state secrets security system, given its generic definition. Research of the basic elements and sub-levels of the system of state secrets security to build its organizational and legal structure, establishment and legal theory and practice-production principles defining its objectives and purpose. The listed orders provide state secrets security, which are part of a single overall order--secrecy. The existing organizational, legal, engineering, cryptographic and operational-search measures to secure state secrets were presented. [ABSTRACT FROM AUTHOR]

Substitution ciphers replace symbols or other parts of the plaintext to ciphertext similar parts. Ciphers using cryptographic gamma have high security level, but a significant disadvantage is the high complexity of the operations and, consequently, much lower speed encryption versus ciphers based overlay gamma. This paper is dedicated to developed information ciphering method using gamma generator which considers the secret key and the open message. The obtained results allow increasing the ciphering speed compared with the block ciphers in ciphertext feedback and output feedback modes, meanwhile providing the cryptographic persistence which is comparable with the block ciphers persistence [ABSTRACT FROM AUTHOR]

In this paper we develop rules for the synthesis of nonlinear direct and reverse cryptographic transformation, as well as formalized the model of construction of elementary functions of extended matrix cryptographic transformation. With the use of matrix models describing the operation extended matrix cryptographic transformation, which were synthesized on the basis of various arguments, a general rule of synthesis of additions. The application of these rules provides a synthesis of reverse operations extended matrix cryptographic transformation with any number of additions. With specific examples confirmed the correctness of the application of received rules for the operation of extended matrix cryptographic transformation synthesized on the basis of three substitutions. The application of the rules generates a basic approach to the construction of the expanded matrix operations cryptographic transformation of the information. These results may find practical application in the development of software and hardware for security systems. [ABSTRACT FROM AUTHOR]

Recent research on key establishment using estimates of the reciprocal electromagnetic channel provides an optimal training approach that maximizes the key rate achievable when each node uses a beamformed antenna array. The work detailed here generalizes this concept by allowing the antennas at the two nodes to be represented by arbitrary transmit current or receive weight distributions modeled using complete basis sets and constrained to reside within fixed apertures. The representation requires that we modify the key rate optimization formulation to incorporate mutual coupling and spatially correlated estimation errors. Application of this modified optimization technique produces both the coefficients of the basis functions representing the current distributions and the optimal training approach that together maximize the achievable key rate. Simulations are used to demonstrate the convergence of the technique as the number of basis functions grows large as well as the behavior of the key rate upper bound for different scenarios. [ABSTRACT FROM PUBLISHER]

Advanced Encryption Standard (AES) block cipher system is widely used in cryptographic applications. Substitution boxes (S-boxes) are a keystone of modern symmetric cryptosystems which bring nonlinearity to the cryptosystems and strengthen their cryptographic security. The S-box component used in classic AES is fixed and not changeable. If the S-box is generated dynamically, the cryptographic strength of AES cipher system would be increased. In this article, we use RC4 and AES Key Expansion algorithms to generate dynamic S-box for AES. The purpose of the proposed approach is to generate more secure S-boxes. The generated S-box will have better results in security analysis. To examine the security, various tests are applied to the new S-box and the results pass all of them. [ABSTRACT FROM AUTHOR]

Publish/subscribe mechanism is a typical many-to-many messaging paradigm when multiple applications want to receive the same message or when a group of applications would like to notify each other. Nonetheless, there exist only a few works that address the security issues for content-based publish/subscribe systems formally. Although the security requirements have been partially addressed by Wang et al., there is no formal definition for all of these security requirements in the literature. As a result, most of the existing schemes do not have any security proof and it is difficult to justify whether those schemes are really secure in practice. Furthermore, there is no comprehensive scheme that satisfies the most essential security requirements at the same time. In this paper, we introduce the first security model for important security requirements of content-based publish/subscribe systems. We also give a new security requirement for publisher authenticity, which means that the publisher is authenticated to publish certain types of notification only, and cannot publish other types of notification. We then exhibit a new scheme which fulfills most of the security requirements. Furthermore, we also provide a comprehensive proof for our concrete construction according to the new model. [ABSTRACT FROM AUTHOR]

Least significant bit matching revisited (LSBMR) steganography uses two adjacent pixels as an embedding unit to conceal secret messages. In each unit, the modification probability of the first pixel is twice the modification probability of the second pixel, thereby causing an asymmetric effect on the statistical distribution of pixel difference in LSBMR for consecutive pixels (LSBMRCP). On the basis of the analysis of this asymmetric effect, a fast steganalytic feature is deduced and an embedding rate estimating method that employs an iteration strategy is proposed. Experimental results show that the steganalytic feature can effectively detect LSBMRCP steganography and that the detection performance is superior to the methods proposed by Tan and Xiong et al. Moreover, the embedding rate estimating method is so accurate that the order of magnitude of prediction error is maintained at 10-2, measured by the mean absolute error, median absolute difference, and interquartile range, thus indicating that the proposed method significantly outperforms the method proposed by Tan. [ABSTRACT FROM AUTHOR]

Silicon physically unclonable functions (PUFs) are circuits that exploit modern manufacturing variations to generate unique signatures for chip authentication and cryptographic key generation. Existing research has focused on improving PUF quality at architectural or design levels, but has ignored opportunities available during fabrication, which is the source of systematic and random variation in (ICs)/PUFs. For typical ICs (where security is not a concern), optical proximity correction (OPC) is used to suppress both these types of variations. However, several prior works have shown that only systematic variations negatively impact PUF quality and random variations are beneficial for PUFs. In this paper, we propose two PUF-aware OPC cost functions: 1) P-OPC generates a PUF lithography mask that increases all variations in PUF circuitry (the opposite of state-of-the-art OPC), and 2) SVC-OPC generates mask patterns that reduce the systematic variation found in PUFs for better quality. Simulation results for ring oscillator (RO) PUFs show that the proposed techniques can improve PUF signature quality compared to current state-of-the-art OPC. [ABSTRACT FROM PUBLISHER]

Vehicles are equipped with more technology with each passing day. Acronyms such as ABS (anti-lock braking system), EBD (electronic brakeforce distribution) or EPS (electric power steering) have become commonplace, and are used as synonyms for safety and comfort. On the contrary, others like EDR (event data recorder) are not as popular. EDR, commonly known as automotive black boxes, are devices used to collect data about a vehicle and its occupants, which can be accessed after an accident to clarify its cause. With the upcoming regulation of the National Highway Traffic Safety Administration requiring manufacturers to include EDR in all new vehicles, privacy advocates have raised some alarms related to the storage of and access to these data. In this article, we propose a novel privacy-aware solution for the EDR of modern vehicles. Our solution is based on modern cryptographic primitives like timed release encryption (TRE), and it guarantees the privacy of the vehicle?s occupants while allowing the full functionality of EDR in case of emergency. [ABSTRACT FROM PUBLISHER]

Many cryptographic systems based on elliptic curves are proven secure in the Random Oracle Model, assuming there exist probabilistic functions that map elements in some domain (e.g. bitstrings) onto uniformly and independently distributed points in a curve. When implementing such systems, and in order for the proof to carry over to the implementation, those mappings must be instantiated with concrete constructions whose behavior does not deviate significantly from random oracles. In contrast to other approaches to public-key cryptography, where candidates to instantiate random oracles have been known for some time, the first generic construction for hashing into ordinary elliptic curves indifferentiable from a random oracle was put forward only recently by Brier et al. We present a machine-checked proof of this construction. The proof is based on an extension of the CertiCrypt framework with logics and mechanized tools for reasoning about approximate forms of observational equivalence, and integrates mathematical libraries of group theory and elliptic curves. [ABSTRACT FROM AUTHOR]

PKCS#11, is a security API for cryptographic tokens. It is known to be vulnerable to attacks which can directly extract, as cleartext, the value of sensitive keys. In particular, the API does not impose any limitation on the different roles a key can assume, and it permits to perform conflicting operations such as asking the token to wrap a key with another one and then to decrypt it. Fixes proposed in the literature, or implemented in real devices, impose policies restricting key roles and token functionalities. In this paper we define a simple imperative programming language, suitable to code PKCS#11 symmetric key management, and we develop a type-based analysis to prove that the secrecy of sensitive keys is preserved under a certain policy. We formally analyse existing fixes for PKCS#11 and we propose a new one, which is type-checkable and prevents conflicting roles by deriving different keys for different roles. We develop a prototype type-checker for a software token emulator written in C and we experiment on various working configurations. [ABSTRACT FROM AUTHOR]

Security policies are critical aspects of secure computer systems. For wireless classified environments enforcing multiple concurrent policies across multiple domains, the design of correct implementation mechanisms is a challenging and difficult task. In order to simplify this task, our research work applies an additional layer of defensive mechanism using steganography to secure data in our multi-domain access control model. In this model, multiple independent policies are specified that describe relationships between sets of entities in the classified environment. These multiple policies are then integrated into a single enclave system by applying an inter-enclave multi-policy classification paradigm for information access using steganography. Our methodology is structured to assist system security managers in reducing the complexity of policy development and implementation, and is applicable to a spectrum of wireless classified environments. [ABSTRACT FROM AUTHOR]

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Fujitsu's Sparc64 X is a processor for Unix servers that runs at a speed of 3 GHz and consists of 16 cores, a 24-Mbyte shared level-2 (L2) cache, memory controllers, I/O controllers, and system controllers for connecting multiple chips. The authors of this article enhanced the microarchitecture and introduced an extended instruction set called High-Performance Computing Arithmetic Computational Extensions (HPC-ACE), used previously in the K computer. The peak memory bandwidth is 102 Gbytes per second. These features realize extremely high-throughput performance. In addition, the authors added new functions to the processor core pipelines, which accelerate certain software tasks such as cryptographic processing. They call these functions "software on chip" (SWoC). Furthermore, they employ high-reliability technology used in mainframes to ensure stable operation of mission-critical systems. This article describes the past and current direction of the microarchitecture of the Sparc64 processor series, gives an overview of Sparc64 X, and presents results of testing the performance and power efficiency of SWoC. [ABSTRACT FROM PUBLISHER]

In this paper, a new set of frequency-hopping sequences is proposed, and the Hamming correlation distribution of the new set is investigated. The construction of new frequency hopping sequences is based upon generalized cyclotomy. It is shown that the proposed frequency-hopping sequence set is optimal with respect to the average Hamming correlation bound. [ABSTRACT FROM AUTHOR]

The structure of additive multivariable codes over $${\mathbb{F}_4}$$ (the Galois field with 4 elements) is presented. The semisimple case (i.e., when the defining polynomials of the code have no repeated roots) is specifically addressed. These codes extend in a natural way the abelian codes, of which additive cyclic codes of odd length are a particular case. Duality of these codes is also studied. [ABSTRACT FROM AUTHOR]

Let p, q be distinct primes with gcd( p − 1, q − 1) = 4. Let D, D, D, D be Whiteman's generalized cyclotomic classes, satisfying the multiplicative group $${{\mathbb Z}^*_{pq}=D_0\cup D_1\cup D_2\cup D_3}$$ . In this paper, we give formulas of Gauss periods: $${\sum_{i\in D_0\cup D_2}\zeta^i}$$ and $${\sum_{i\in D_0}\zeta^i}$$ , where $${\zeta}$$ is a pqth primitive root of unity. As an application, we get the maximum cross-correlation amplitudes of three codebooks from generalized cyclotomic sets of order four and supply conditions on p and q such that they nearly meet the Welch bound. [ABSTRACT FROM AUTHOR]

Kantor and Williams (Trans Am Soc 356:895-938, ) introduced a family of non-desarguesian symplectic semifields of even order and studied a number of structures connected with such semifields; namely, symplectic spreads, orthogonal spreads and Z-linear codes. Also, they provided equivalence results concerning such objects, although under certain field restrictions. In this article we will succeed in removing such hypotheses. [ABSTRACT FROM AUTHOR]

We classify up to equivalence all optimal binary self-dual [52, 26, 10] codes having an automorphism of order 3 with 10 fixed points. We achieve this using a method for constructing self-dual codes via an automorphism of odd prime order. We study also codes with an automorphism of order 3 with 4 fixed points. Some of the constructed codes have new values β = 8, 9, and 12 for the parameter in their weight enumerator. [ABSTRACT FROM AUTHOR]

We show that the established necessary conditions for a GBRD $${(v,3,\lambda; \mathbb {G})}$$ are sufficient ( i) when $${\mathbb {G}}$$ is supersolvable and ( ii) when $${\mathbb {G}}$$ is solvable with $${\vert \mathbb {G} \vert }$$ prime to 3. [ABSTRACT FROM AUTHOR]

In this paper we study identifying codes, locating-dominating codes, and total-dominating codes in Sierpiński graphs. We compute the minimum size of such codes in Sierpiński graphs. [ABSTRACT FROM AUTHOR]

Cloud computing has showed up as a popular design in managing world to back up managing large volumetric details using cluster of commodity computer systems. It is the newest effort in offering and managing computing as a service. Either program or Application, it is used to describe both. A cloud computing paradigm dynamically assigns, configures, relocates and de provisions these computing resources as needed. it also describes applications that are to be extended accessible through the Internet. Data security and availability management is one of the most complex ongoing studies in cloud managing, because of clients outsourcing their sensitive details to cloud service providers. Current alternatives that use genuine cryptographic techniques to reduce these security and availability management problems suffer from heavy computational cost on both data owner as well as the cloud service provider for key distribution and management. This paper capability based access control addresses this challenging problem to ensure only valid users will access the outsourced data. It reduces burden over the data owner for key management it is proposed to maintain key management in the cloud it self. This work also proposes some modifications in Diffie-Hellman key exchange protocol to thwart from man in middle attack between cloud service provider and the user for secretly sharing a symmetric key for secure data access that alleviates the problem of key distribution and management at cloud service provider. The simulation run and research reveals that the recommended strategy is highly efficient and secured under current security designs. [ABSTRACT FROM AUTHOR]

We continue the study of locally computable pseudorandom generators (PRGs) G : {0, 1}n → {0, 1}m such that each of their outputs depends on a small number d of input bits. While it is known that such generators are likely to exist for the case of small sublinear stretch m = n + n1-δ, it is less clear whether achieving larger stretch such as m = n + Ω(n) or even m = n1+δ is possible. The existence of such PRGs, which was posed as an open question in previous works, has recently gained an additional motivation due to several interesting applications. We make progress towards resolving this question by obtaining several local constructions based on the onewayness of "random" local functions--a variant of an assumption made by Goldreich [Candidate one-way functions based on exporter graphs, 7 (ECCC 2000), TRCO-090]. Specifically, we construct collections of PRGs with the following parameters: (1) linear stretch m = n + Ω(n) and constant locality d = O(1); (2) polynomial stretch m = n1+δ and any (arbitrarily slowly growing) superconstant locality d = ω(1), e.g., log* n; (3) polynomial stretch m = n1+δ, constant locality d = O(1), and inverse polynomial distinguishing advantage (as opposed to the standard case of n-ω(1)). Our constructions match the parameters achieved by previous "ad hoc" candidates and are the first to do this under a one-wayness assumption. At the core of our results lies a new search-to-decision reduction for random local functions. This reduction also shows that some of the previous PRG candidates can be based on one-wayness assumptions. Altogether, our results fortify the existence of local PRGs of long stretch. As an additional contribution, we show that our constructions give rise to strong inapproximability results for the densest-subgraph problem in d-uniform hypergraphs for constant d. This allows us to improve the previous bounds of Feige [Relations between average case complexity and approximation complexity, in Proceedings of STOC 2002, pp. 534-543] and Khot [Ruling out PTAS for graph min-bisection-densest subgraph and bipartate clique, in Proceedings of FOCS 2004, pp. 136-145] from constant inapproximability factor to nε-inapproximability, at the expense of relying on stronger assumptions. [ABSTRACT FROM AUTHOR]

We construct a Non-Malleable Chosen Ciphertext Attack (NM-CCA1) encryption scheme from any encryption scheme that is also plaintext aware and weakly simulatable. We believe this is the first construction of a NM-CCA1 scheme that follows strictly from encryption schemes with seemingly weaker or incomparable security definitions to NM-CCA1.Previously, the statistical Plaintext Awareness #1 (PA1) notion was only known to imply CCA1. Our result is therefore novel because unlike the case of Chosen Plaintext Attack (CPA) and Chosen Chiphertext Attack (CCA2), it is unknown whether a CCA1 scheme can be transformed into an NM-CCA1 scheme. Additionally, we show both the Damgård Elgamal Scheme (DEG) [in: CRYPTO, J. Feigenbaum, ed., Lecture Notes in Computer Science, Vol. 576, Springer, 1991, pp. 445-456] and the Cramer-Shoup Lite Scheme (CS-Lite) [SIAM J. Comput. 33(1) (2003), 167-226] are weakly simulatable under the DDH assumption. Since both are known to be statistical Plaintext Aware 1 (PA1) under the Diffie-Hellman Knowledge (DHK) assumption, they instantiate our scheme securely.Furthermore, in response to a question posed by Matsuda and Matsuura [in: Public Key Cryptography, D. Catalano, N. Fazio, R. Gennaro and A. Nicolosi, eds, Lecture Notes in Computer Science, Vol. 6571, Springer, 2011, pp. 246-264], we define cNM-CCA1-security in which an NM-CCA1-adversary is permitted to ask a c≥⃒1 number of parallel queries after receiving the challenge ciphertext. We extend our construction to yield a cNM-CCA1 scheme for any constant c. All of our constructions are black-box. [ABSTRACT FROM AUTHOR]

Steganography is the art and science of hiding data in different media such as texts, audios, images, and videos. Data hiding techniques are generally divided into two groups: spatial and frequency domain techniques. Spatial domain methods generally have low security and, as a result, are less attractive to researchers. Discrete cosine transform (DCT) is the most common transform domain used in steganography and JPEG compression. Since a large number of the DCT coefficients of JPEG images are zero, the capacity of DCT domain-based steganography methods is not very high. We present a high-capacity method for hiding messages in the DCT domain. We describe the method in two classes where the receiver has and where the receiver does not have the cover image. In each class, we consider three cases for each coefficient. By considering n coefficients, there are 3n different situations. The method embeds log2 3n bits in these n coefficients. We show that the maximum reachable capacity by our method is 58% higher than the other general steganography methods. Experimental results show that the histogram-based steganalysis methods cannot detect the stego images produced by the proposed method while the capacity is increased significantly. [ABSTRACT FROM AUTHOR]

The current JPEG steganalysis systems, which include various strategies for feature extraction, have attained outstanding achievements. However, a common shortcoming is that they are always conducted on the entire image and do not take advantage of the content diversity. In addition, compared with a low-dimensional feature set, an appropriate rich model with high-dimensional features can obtain substantial improvement in steganalysis performances. A new steganalysis algorithm based on image segmentation is proposed which enables us to utilize the content characteristics of JPEG images. The given images are segmented to several subimages according to the texture complexity and then high-dimensional steganalysis features of each sort of subimages with the same or close texture complexity are extracted separately to build a classifier. The steganalysis results of the whole image are figured out through a weighted fusing process of all categories of the subimages. Experimental results demonstrate that the proposed method exhibits excellent performances and improves the detection accuracy. [ABSTRACT FROM AUTHOR]

This work presents adaptive image steganography methods which locate suitable regions for embedding by contourlet transform, while embedded message bits are carried in discrete cosine transform coefficients. The first proposed method utilizes contourlet transform coefficients to select contour regions of the image. In the embedding procedure, some of the contourlet transform coefficients may change which may cause errors at the message extraction phase. We propose a novel iterative procedure to resolve such problems. In addition, we have proposed an improved version of the first method in which it uses an advanced embedding operation to boost its security. Experimental results show that the proposed base method is an imperceptible image steganography method with zero retrieval error rate. Comparisons with other steganography methods which utilize contourlet transform show that our proposed method is able to retrieve all messages perfectly, whereas the others fail. Moreover, the proposed method outperforms the ContSteg method in terms of PSNR and the higher-order statistics steganalysis method. Experimental evaluations of our methods with the well known DCTbased steganography algorithms have demonstrated that our improved method has superior performance in terms of PSNR and SSIM, and is more secure against the steganalysis attack. [ABSTRACT FROM AUTHOR]

A polynomial technique for estimating a steganographic capacity (SC) of a stego channel formed with least-significant-bit (LSB) modification approach was developed within the framework of steganalysis efficiency-improvement job based on general approach to analysis of the status and performance of information systems. Digital images of lossy compression formats were used as cover objects. The technique developed is important to implement decoding of additional data embedded in a cover object. With respect to stego transformation with LSB approach, a relationship between the rate-of-change of smallest singular values of image blocks (i.e., submatrices) and SC value was established. It was empirically established that the absolute error of SC obtained by the developed technique is essentially independent of its true value, but dependent on the number of stego messages (images) subjected to analysis. [ABSTRACT FROM AUTHOR]

This article describes a possibly-1920s vintage cipher machine that has been on display at HMS Collingwood Naval Radio Museum. The construction of the machine is described, and the mechanism involved in enciphering is traced. The origin is unknown, and it may possibly be a well-constructed prototype. The keyboard contains the normal alphabet plus 10 digits. The scrambling is achieved by electrically-conducting cross-connections of adjacent rows in a 36 × 2 matrix inside a rotatable drum. This would imply a 36 × Factorial 36 set of possible wiring patterns within the rotatable drum. [ABSTRACT FROM PUBLISHER]

This article discusses a first-year seminar taught at Gettysburg College about the mathematics, history, and ethics of cryptography. The author discusses how he structures his course and offers advice to other faculty interested in starting such a course. [ABSTRACT FROM PUBLISHER]

In a previous article [5], the authors have presented some examples of cryptography in Morocco before the sixteenth century. In the present article, they continue to describe other methods of cryptography and steganography used by Moroccans between the seventeenth and the nineteenth centuries. In particular, there was intense use of the Hissab al Jomal calculation to encrypt numbers and use of a grid filled with verses of poetry in the form of a chessboard to write a given message. [ABSTRACT FROM PUBLISHER]

This article presents Christian ciphers (counterparts of the well-known Hebrew atbah cipher) used in main languages and scripts of the Christan Orient: in Greek, Coptic, and Syriac, in Late Antiquity and the Middle Ages. The article also describes other alphabetic substitution ciphers used in these languages and highlights numerical rules in their construction. [ABSTRACT FROM PUBLISHER]

In order to improve the security of batch steganography, this paper proposed a novel adaptive batch steganography system. First, it estimated embedding capacity of images under current steganalysis techniques by bringing ensemble classifier based on random forest into steganalysis, then distributed message bits to the images according to their embedding capacities. The new system could make full use of the images and improve batch steganography security further by dividing the message into groups. Experimental results show that the new security definition decreases the total detection error and running time, having a good balance between missed detection rate and false alarm rate. [ABSTRACT FROM AUTHOR]

Throughput, flexibility, and security form the design trilogy of reconfigurable crypto engines; they must be carefully considered without reducing the major role of classical design constraints, such as surface, power consumption, dependability, and cost. Applications such as network security, Virtual Private Networks (VPN), Digital RightsManagement (DRM), and pay per view have drawn attention to these three constraints. For more than ten years, many studies in the field of cryptographic engineering have focused on the design of optimized high-throughput hardware cryptographic cores (e.g., symmetric and asymmetric key block ciphers, stream ciphers, and hash functions). The flexibility of cryptographic systems plays a very important role in their practical application. Reconfigurable hardware systems can evolve with algorithms, face up to new types of attacks, and guarantee interoperability between countries and institutions. The flexibility of reconfigurable crypto processors and crypto coprocessors has reached new levels with the emergence of dynamically reconfigurable hardware architectures and tools. Last but not least, the security of systems that handle confidential information needs to be thoroughly evaluated at the design stage in order to meet security objectives that depend on the importance of the information to be protected and on the cost of protection. Usually, designers tackle security problems at the same time as other design constraints and in many cases target only one security objective, for example, a side-channel attack countermeasures, fault tolerance capability, or the monitoring of the device environment. Only a few authors have addressed all three design constraints at the same time. In particular, key management security (e.g., secure key generation and transmission, the use of a hierarchical key structure composed of session keys and master keys) has frequently been neglected to the benefit of performance and/or flexibility. Nevertheless, a few authors propose original processor architectures based on multi-crypto-processor structures and reconfigurable cryptographic arrays. In this article,we review publishedworks on symmetric key crypto engines and present current trends and design challenges. [ABSTRACT FROM AUTHOR]

As a feasible model for signing quantum messages, some cryptanalysis and improvement of arbitrated quantum signature (AQS) have received a great deal of attentions in recent years. However, in this paper we find the previous improvement is not suitable implemented in some typical AQS protocols in the sense that the receiver, Bob, can forge a valid signature under known message attack. We describe the forgery strategy and present some corresponding improved strategies to stand against the forgery attack by modifying the encryption algorithm, an important part of AQS. These works preserve the merits of AQS and lead some potential improvements of the security in quantum signature or other cryptography problems. [ABSTRACT FROM AUTHOR]

The Publication pattern, Relative Growth Rate (RGR), Doubling time (Dt), Country-wise distribution and Subject-wise papers of Cryptography published during 2000-2011 were analyzed. This bibliometric study was made using the data retrieved from the Web of Science (WoS) through the filter of the category in Cryptography as a subject search. A total number of 6610 records which were retrieved from the Web of Science was used to assess the academic productivity and distribution of research diversity of cryptography field from four major countries -China, USA, Taiwan and Japan which contributed more papers in cryptography and allied field of researches. The highest RGR is 0.44 in 2002 and Dt is 21. 656 in 2008 measured during the period. China was the country with the highest productivity rare and the most-frequent partners among the collaborative papers at global level. [ABSTRACT FROM AUTHOR]

ABSTRACT A fair exchange protocol allows two entities to exchange digital signatures over open networks in a fair way, so that either each entity obtains the other's signature or neither entity does. Fair exchange protocol plays an important role in electronic commerce in the case of exchanging digital contracts. In this paper, we propose a fair exchange protocol based on identity-based verifiably encrypted signatures. Our protocol involves an offline trusted third party which is only required when one entity attempts to cheat or crashes. The underlining identity-based verifiably encrypted signature scheme is proven secure under the computational Diffie-Hellman assumption and is the first identity-based verifiably encrypted signature scheme provably secure against existential unforgeable under adaptive chosen message and identity attacks in the standard model. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT To produce ciphertexts, two modes of encryption are applied-block ciphers, which encrypt a fixed size block of plaintext at a time, and stream ciphers, which encrypt stream data, one or more bits at a time. As one of stream ciphers, the cipher feedback (CFB) mode is implemented by a block cipher via multiple stages, and in each stage, 1 bit or a number of bits of plaintext are encrypted at a time. Throughout this paper, the study will focus upon the error performance of the stream-based CFB under two sliding-window protocols, go-back-N and selective-reject, in an error channel in terms of throughput. We model the performance of the CFB in terms of application-level throughput and derive the number of stages needed to achieve the optimal throughput, under a given error rate in an error channel. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]