Semantic Security and Indistinguishability in the Quantum World

At CRYPTO 2013, Boneh and Zhandry initiated the study of quantum-secure encryption. They proposed first indistinguishability definitions for the quantum world where the actual indistinguishability only holds for classical messages, and they provide arguments why it might be hard to achieve a stronger notion. In this work, we show that stronger notions are achievable, where the indistinguishability holds for quantum superpositions of messages. We investigate exhaustively the possibilities and subtle differences in defining such a quantum indistinguishability notion for symmetric-key encryption schemes. We justify our stronger definition by showing its equivalence to novel quantum semantic-security notions that we introduce. Furthermore, we show that our new security definitions cannot be achieved by a large class of ciphers -- those which are quasi-preserving the message length. On the other hand, we provide a secure construction based on quantum-resistant pseudorandom permutations; this construction can be used as a generic transformation for turning a large class of encryption schemes into quantum indistinguishable and hence quantum semantically secure ones. Moreover, our construction is the first completely classical encryption scheme shown to be secure against an even stronger notion of indistinguishability, which was previously known to be achievable only by using quantum messages and arbitrary quantum encryption circuits.Comment: 37 pages, 2 figure

Novel Framework for Hidden Data in the Image Page within Executable File Using Computation between Advanced Encryption Standard and Distortion Techniques

The hurried development of multimedia and internet allows for wide distribution of digital media data. It becomes much easier to edit, modify and duplicate digital information. In additional, digital document is also easy to copy and distribute, therefore it may face many threats. It became necessary to find an appropriate protection due to the significance, accuracy and sensitivity of the information. Furthermore, there is no formal method to be followed to discover a hidden data. In this paper, a new information hiding framework is presented.The proposed framework aim is implementation of framework computation between advance encryption standard (AES) and distortion technique (DT) which embeds information in image page within executable file (EXE file) to find a secure solution to cover file without change the size of cover file. The framework includes two main functions; first is the hiding of the information in the image page of EXE file, through the execution of four process (specify the cover file, specify the information file, encryption of the information, and hiding the information) and the second function is the extraction of the hiding information through three process (specify the stego file, extract the information, and decryption of the information).Comment: 6 Pages IEEE Format, International Journal of Computer Science and Information Security, IJCSIS 2009, ISSN 1947 5500, Impact Factor 0.42

Cryptanalysis of Masked Ciphers: A not so Random Idea

A new approach to the security analysis of hardware-oriented masked ciphers against second-order side-channel attacks is developed. By relying on techniques from symmetric-key cryptanalysis, concrete security bounds are obtained in a variant of the probing model that allows the adversary to make only a bounded, but possibly very large, number of measurements. Specifically, it is formally shown how a bounded-query variant of robust probing security can be reduced to the linear cryptanalysis of masked ciphers. As a result, the compositional issues of higher-order threshold implementations can be overcome without relying on fresh randomness. From a practical point of view, the aforementioned approach makes it possible to transfer many of the desirable properties of first-order threshold implementations, such as their low randomness usage, to the second-order setting. For example, a straightforward application to the block cipher LED results in a masking using less than 700 random bits including the initial sharing. In addition, the cryptanalytic approach introduced in this paper provides additional insight into the design of masked ciphers and allows for a quantifiable trade-off between security and performance

An Overview of Parallel Symmetric Cipher of Messages

مقدمة: على الرغم من التطورات الهامة في الاتصالات والتكنولوجيا، فقد أثبتت حماية البيانات نفسها كواحدة من أكبر الاهتمامات. يجب تشفير البيانات من أجل الارتباط بشكل آمن وسريع من خلال نقل البيانات التكنولوجية على شبكة الإنترنت. يمكن تعريف عملية التشفير بانها تحويل النص العادي إلى نص مشفر لا يمكن قراءته أو تغييره بواسطة الأشخاص المؤذيين.            طرق العمل: من أجل الحفاظ على الدرجة المطلوبة من الأمان ، استغرقت كل من عمليات تحليل التشفير وفك التشفير وقتًا طويلاً. ومع ذلك, من أجل تقليل مقدار الوقت المطلوب لإكمال عمليات التشفير وفك التشفير، طبق العديد من الباحثين طريقة التشفير بطريقة موازية. لقد كشف البحث الذي تم إجراؤه حول المشكلة عن العديد من الإجابات المحتملة. استخدم الباحثون التوازي لتحسين إنتاجية خوارزمياتهم، مما سمح لهم بتحقيق مستويات أداء أعلى في خوارزمية التشفير.                             النتائج: أظهرت الأبحاث الحديثة حول تقنيات التشفير المتوازي أن وحدات معالجة الرسومات (GPUs) تعمل بشكل أفضل من الأنظمة الأساسية المتوازية الأخرى عند مقارنة مستويات أداء التشفير.   الاستنتاجات: لإجراء بحث مقارنة حول أهم خوارزميات التشفير المتوازية من حيث فعالية أمن البيانات وطول المفتاح والتكلفة والسرعة، من بين أمور أخرى. تستعرض هذه الورقة العديد من الخوارزميات المتوازية الهامة المستخدمة في تشفير البيانات وفك تشفيرها في جميع التخصصات. ومع ذلك، يجب النظر في معايير أخرى لإظهار مصداقية أي تشفير. تعتبر اختبارات العشوائية مهمة جدًا لاكتشافها وتم تسليط الضوء عليها في هذه الدراسة.                                                              Background: Despite significant developments in communications and technology, data protection has established itself as one of the biggest concerns. The data must be encrypted in order to link securely, quickly through web-based technological data transmission. Transforming plain text into ciphered text that cannot be read or changed by malicious people is the process of encryption. Materials and Methods: In order to maintain the required degree of security, both the cryptanalysis and decryption operations took a significant amount of time. However, in order to cut down on the amount of time required for the encryption and decryption operations to be completed, several researchers implemented the cryptography method in a parallel fashion. The research that has been done on the problem has uncovered several potential answers. Researchers used parallelism to improve the throughput of their algorithms, which allowed them to achieve higher performance levels on the encryption algorithm. Results: Recent research on parallel encryption techniques has shown that graphics processing units (GPUs) perform better than other parallel platforms when comparing their levels of encryption performance. Conclusion: To carry out comparison research on the most significant parallel crypto algorithms in terms of data security efficacy, key length, cost, and speed, among other things. This paper reviews various significant parallel algorithms used for data encryption and decryption in all disciplines. However, other criteria must be considered in order to show the trustworthiness of any encryption. Randomness tests are very important to discover and are highlighted in this study

Quantum Noise Randomized Ciphers

We review the notion of a classical random cipher and its advantages. We sharpen the usual description of random ciphers to a particular mathematical characterization suggested by the salient feature responsible for their increased security. We describe a concrete system known as AlphaEta and show that it is equivalent to a random cipher in which the required randomization is effected by coherent-state quantum noise. We describe the currently known security features of AlphaEta and similar systems, including lower bounds on the unicity distances against ciphertext-only and known-plaintext attacks. We show how AlphaEta used in conjunction with any standard stream cipher such as AES (Advanced Encryption Standard) provides an additional, qualitatively different layer of security from physical encryption against known-plaintext attacks on the key. We refute some claims in the literature that AlphaEta is equivalent to a non-random stream cipher.Comment: Accepted for publication in Phys. Rev. A; Discussion augmented and re-organized; Section 5 contains a detailed response to 'T. Nishioka, T. Hasegawa, H. Ishizuka, K. Imafuku, H. Imai: Phys. Lett. A 327 (2004) 28-32 /quant-ph/0310168' & 'T. Nishioka, T. Hasegawa, H. Ishizuka, K. Imafuku, H. Imai: Phys. Lett. A 346 (2005) 7

An enhanced Blowfish Algorithm based on cylindrical coordinate system and dynamic permutation box

The Blowfish Algorithm (BA) is a symmetric block cipher that uses Feistel network to iterate simple encryption and decryption functions. BA key varies from 32 to 448 bits to ensure a high level of security. However, the substitution box (S-Box) in BA occupies a high percentage of memory and has problems in security, specifically in randomness of output with text and image files that have large strings of identical bytes. Thus, the objective of this research is to enhance the BA to overcome these problems. The research involved three phases, algorithm design, implementation, and evaluation. In the design phase, a dynamic 3D S-Box, a dynamic permutation box (P-Box), and a Feistal Function (F-Function) were improved. The improvement involved integrating Cylindrical Coordinate System (CCS) and dynamic P-Box. The enhanced BA is known as Ramlan Ashwak Faudziah (RAF) algorithm. The implementation phase involved performing key expansion, data encryption, and data decryption. The evaluation phase involved measuring the algorithm in terms of memory and security. In terms of memory, the results showed that the RAF occupied 256 bytes, which is less than the BA (4096 bytes). In terms of randomness of text and image files that have large strings of identical bytes, the average rate of randomness for 188 statistical tests obtained values of more than 96%. This means that the RAF has high randomness indicating that it is more secured. Thus, the results showed that the RAF algorithm that integrates the CCS and dynamic P-Box serves as an effective approach that can consume less memory and strengthen security

Deterministic Chaos in Digital Cryptography

This thesis studies the application of deterministic chaos to digital cryptography. Cryptographic systems such as pseudo-random generators (PRNG), block ciphers and hash functions are regarded as a dynamic system (X, j), where X is a state space (Le. message space) and f : X -+ X is an iterated function. In both chaos theory and cryptography, the object of study is a dynamic system that performs an iterative nonlinear transformation of information in an apparently unpredictable but deterministic manner. In terms of chaos theory, the sensitivity to the initial conditions together with the mixing property ensures cryptographic confusion (statistical independence) and diffusion (uniform propagation of plaintext and key randomness into cihertext). This synergetic relationship between the properties of chaotic and cryptographic systems is considered at both the theoretical and practical levels: The theoretical background upon which this relationship is based, includes discussions on chaos, ergodicity, complexity, randomness, unpredictability and entropy. Two approaches to the finite-state implementation of chaotic systems (Le. pseudo-chaos) are considered: (i) floating-point approximation of continuous-state chaos; (ii) binary pseudo-chaos. An overview is given of chaotic systems underpinning cryptographic algorithms along with their strengths and weaknesses. Though all conventional cryposystems are considered binary pseudo-chaos, neither chaos, nor pseudo-chaos are sufficient to guarantee cryptographic strength and security. A dynamic system is said to have an analytical solution Xn = (xo) if any trajectory point Xn can be computed directly from the initial conditions Xo, without performing n iterations. A chaotic system with an analytical solution may have a unpredictable multi-valued map Xn+l = f(xn). Their floating-point approximation is studied in the context of pseudo-random generators. A cryptographic software system E-Larm ™ implementing a multistream pseudo-chaotic generator is described. Several pseudo-chaotic systems including the logistic map, sine map, tangent- and logarithm feedback maps, sawteeth and tent maps are evaluated by means of floating point computations. Two types of partitioning are used to extract pseudo-random from the floating-point state variable: (i) combining the last significant bits of the floating-point number (for nonlinear maps); and (ii) threshold partitioning (for piecewise linear maps). Multi-round iterations are produced to decrease the bit dependence and increase non-linearity. Relationships between pseudo-chaotic systems are introduced to avoid short cycles (each system influences periodically the states of other systems used in the encryption session). An evaluation of cryptographic properties of E-Larm is given using graphical plots such as state distributions, phase-space portraits, spectral density Fourier transform, approximated entropy (APEN), cycle length histogram, as well as a variety of statistical tests from the National Institute of Standards and Technology (NIST) suite. Though E-Larm passes all tests recommended by NIST, an approach based on the floating-point approximation of chaos is inefficient in terms of the quality/performance ratio (compared with existing PRNG algorithms). Also no solution is known to control short cycles. In conclusion, the role of chaos theory in cryptography is identified; disadvantages of floating-point pseudo-chaos are emphasized although binary pseudo-chaos is considered useful for cryptographic applications.Durand Technology Limite