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Computing isogenies between elliptic curves is a significant part of post-quantum cryptography with many practical applications (for example, in SIDH, SIKE, B-SIDH, or CSIDH algorithms). Comparing to other post-quantum algorithms, the main advantages of these protocols are smaller keys, the similar idea as in the ECDH, and a large basis of expertise about elliptic curves. The main disadvantage of the isogeny-based cryptosystems is their computational efficiency - they are slower than other post-quantum algorithms (e.g., lattice-based). That is why so much effort has been put into improving the hitherto known methods of computing isogenies between elliptic curves. In this paper, we present new formulas for computing isogenies between elliptic curves in the extended Jacobi quartic form with two methods: by transforming such curves into the short Weierstrass model, computing an isogeny in this form and then transforming back into an initial model or by computing an isogeny directly between two extended Jacobi quartics. [ABSTRACT FROM AUTHOR]

The article presents the front cover of the periodical "Journal of Mathematical Cryptology", along with the names of the editorial board, publishing details such as disclaimers, and table of contents which includes Cartesian codes, linear algebra and geometry.

Attribute-based signature (ABS) is a novel cryptographic primitive, which can make the signing party sign a message with fine-grained control over identifying information. ABS only reveals the fact that the verified message must be signed by a user with a set of attributes satisfying a predicate. Thus, ABS can hide any identifying information and make fine-grained control on signing. Presently, many attribute-based signature schemes have been proposed, but most of them are not very efficient. Maji et al. recently presented a complete definition and construction about ABS for monotone predicates and showed three instantiations under their framework for ABS. Although the most practical one of their instantiations is efficient, the instantiation is constructed in the generic group model and has been proved to be insecure. Then, Okamoto et al. proposed an attribute-based signature scheme in the standard model, which can support generalized non-monotone predicates over access structure. However, their scheme is not efficient in practice. In this paper, we present a framework for ABS and show a detailed security model for ABS. Under our framework, we present an attribute-based signature scheme for monotone predicates in the standard model, where we choose the Waters' signature scheme as the prototype of our attribute-based signature scheme. Compared with the Maji's scheme in the generic group model, the proposed scheme is constructed in the standard model. Furthermore, compared with the Okamoto's scheme, the proposed scheme is more efficient by decreasing the computation cost. [ABSTRACT FROM AUTHOR]

This article explains, demonstrates, and evaluates Chaum’s protocol for detecting a man-in-the-middle (MitM) of text-messaging network communications. MitM attacks pose serious risks to many network communications. Networks often mitigate these risks with robust protocols, such as TLS, which assume some type of public-key infrastructure that provides a mechanism for the authenticated exchange of public keys. By contrast, Chaum’s protocol aims to detect a MitM withminimalassumptions and technology, and in particular without assuming the authenticated exchange of public keys. Chaum assumes that the eavesdropper can “sound like” the communicants but that the eavesdropper cannot fabricate sensible conversations. Using an encryption function and one-way function, Chaum’s protocol works in three phases. In Phase I, the communicants exchange their public keys. In Phase II, each communicant generates a random string. The first communicant cryptographically commits to that string, and sends the string to the other communicant after receiving the other’s string. In Phase III, using any of four different “scenarios” the communicants verify that each possesses the same two strings. The protocol forces any MitM to cause the communicants to possess different pairs of strings. The text-messaging scenario is similar to a forced-latency protocol proposed by Wilcox-O’Hearn in 2003. This article implements and experimentally demonstrates the effectiveness of the third scenario, which uses timing to detect a MitM in text-messaging. Even assuming a MitM can send messages without any network latency, the protocol forces the MitM to cause delays noticeable by the communicants. This article is the first to explain, demonstrate, and evaluate Chaum’s protocol, which Chaum described only in an abandoned and nearly inscrutable patent application. [ABSTRACT FROM AUTHOR]

The article presents research on the significance of rapid data exchange in keeping a secret for 24 hours at the University of Geneva in Switzerland. Topics discussed include the use of cryptography in sending coded messages, the complementary cryptographic tasks, and the association of physics-based information security with quantum mechanics.

Providing secured and seamless service is one of the most important aspects of mobile networks, particularly for mobile WiMAX systems. However, the long delay handover schemes brought by the time-consuming EAP-based authentication may cause service disruption when a mobile WiMAX user moves between the coverage areas of different base stations. In this paper, we propose a handover scheme using symmetric key cryptography and pre-authentication approach to shorten the delay while ensuring high security level for Mobile WiMAX handover. The scheme is proven by BAN logic to achieve the security goals of an authentication scheme. A performance analysis is also carried out to show the effectiveness of this scheme in reducing handover delay and saving computational resources. [ABSTRACT FROM AUTHOR]

Statistical analysis of attacks on symmetric ciphers often requires assuming the normal behaviour of a test statistic. Typically such an assumption is made in an asymptotic sense. In this work, we consider concrete versions of some important normal approximations that have been made in the literature. To do this, we use the Berry-Esséen theorem to derive explicit bounds on the approximation errors. A basic mathematical requirement is that such approximation errors should be within reasonable bounds, a point which appears to have been overlooked in many of the earlier works on statistical aspects of cryptanalysis. Interpreting the error bounds in the cryptanalytic context yields several surprising results. One important implication is that this puts in doubt the applicability of the order statistics based approach for analysing key recovery attacks on block ciphers. This approach has been earlier used to obtain several results on the data complexities of (multiple) linear and differential cryptanalysis. The non-applicability of the order statistics based approach puts a question mark on the data complexities obtained using this approach. Fortunately, we are able to recover all of these results by utilising the hypothesis testing framework. This, however, necessitates using normal approximations for the χ² and the LLR test statistics considered in earlier works. These approximations themselves have issues which seem to be difficult to resolve satisfactorily. More generally, the message of our work is that all cryptanalytic attacks should properly derive and interpret the error bounds for any (normal) approximation that is made. [ABSTRACT FROM AUTHOR]

A hash function secure in the indifferentiability framework (TCC 2004) is able to resist all meaningful generic attacks. Such hash functions also play a crucial role in establishing the security of protocols that use them as random functions. To eliminate multi-collision type attacks on the Merkle-Damgård mode (Crypto 1989), Lucks proposed widening the size of the internal state of hash functions (Asiacrypt 2005). The fast wide pipe (FWP) hash mode was introduced by Nandi and Paul at Indocrypt 2010, as a faster variant of Lucks' wide pipe mode. Despite the higher speed, the proven indifferentiability bound of the FWP mode has so far been only up to the birthday barrier of n/2 bits. The main result of this paper is the improvement of the FWP bound to 2n/3 bits (up to an additive constant). We also provide evidence that the bound may be extended beyond 2n/3 bits. [ABSTRACT FROM AUTHOR]

Attribute-based Encryption (ABE) is regarded as a promising cryptographic conducting tool to guarantee data owners’ direct control over their data in public cloud storage. The earlier ABE schemes involve only one authority to maintain the whole attribute set, which can bring a single-point bottleneck on both security and performance. Subsequently, some multi-authority schemes are proposed, in which multiple authorities separately maintain disjoint attribute subsets. However, the single-point bottleneck problem remains unsolved. In this paper, from another perspective, we conduct a threshold multi-authority CP-ABE access control scheme for public cloud storage, named TMACS, in which multiple authorities jointly manage a uniform attribute set. In TMACS, taking advantage of ($t,n$ ) threshold secret sharing, the master key can be shared among multiple authorities, and a legal user can generate his/her secret key by interacting with any $t$ authorities. Security and performance analysis results show that TMACS is not only verifiable secure when less than $t$ authorities are compromised, but also robust when no less than $t$ authorities are alive in the system. Furthermore, by efficiently combining the traditional multi-authority scheme with TMACS, we construct a hybrid one, which satisfies the scenario of attributes coming from different authorities as well as achieving security and system-level robustness. [ABSTRACT FROM PUBLISHER]

We propose a loss tolerant quantum private query (QPQ) protocol based on two non-orthogonal states and unambiguous state discrimination (USD) measurement. By analyzing a two-point attack by a third party, we find that our protocol has a stronger ability to resist external attacks than G-protocol and Y-protocol. Our protocol requires a smaller number of compressions than that in G-protocol (Gao et al., Opt. Exp. 2012, 20, 17411-17420) and Y-protocol (Yan et al. Quant. Inf. Process. 2014, 13, 805-813), which means less post-processing. Our protocol shows better database security and user privacy compared with G-protocol. [ABSTRACT FROM AUTHOR]

We introduce two new Kirchhoff-law-Johnson-noise (KLJN) secure key distribution schemes which are generalizations of the original KLJN scheme. The first of these, the Random-Resistor (RR-) KLJN scheme, uses random resistors with values chosen from a quasi-continuum set. It is well-known since the creation of the KLJN concept that such a system could work in cryptography, because Alice and Bob can calculate the unknown resistance value from measurements, but the RR-KLJN system has not been addressed in prior publications since it was considered impractical. The reason for discussing it now is the second scheme, the Random Resistor Random Temperature (RRRT-) KLJN key exchange, inspired by a recent paper of Vadai, Mingesz and Gingl, wherein security was shown to be maintained at non-zero power flow. In the RRRT-KLJN secure key exchange scheme, both the resistances and their temperatures are continuum random variables. We prove that the security of the RRRT-KLJN scheme can prevail at a non-zero power flow, and thus the physical law guaranteeing security is not the Second Law of Thermodynamics but the Fluctuation-Dissipation Theorem. Alice and Bob know their own resistances and temperatures and can calculate the resistance and temperature values at the other end of the communication channel from measured voltage, current and power-flow data in the wire. However, Eve cannot determine these values because, for her, there are four unknown quantities while she can set up only three equations. The RRRT-KLJN scheme has several advantages and makes all former attacks on the KLJN scheme invalid or incomplete. [ABSTRACT FROM AUTHOR]

This paper presents the design and implementation of a key distribution protocol over public channels. This protocol has its own source of randomness, based on data from civil air traffic. An equivalent protocol scheme has been developed according to the theoretical protocol, "satellite scenario". Both parties to generate symmetric keys without preshared secrets have been allowed. Keys generated in this way can be used with symmetric encryption (AES, DES). The performance of the proposed protocol has been conducted with rigorous theoretical information analysis. [ABSTRACT FROM AUTHOR]

The development history ofUmkehrwalze Dora, Enigma's pluggable reflector, is presented from the first ideas in the mid-1920s to the last development plans and its actual usage in 1945. An Enigma message in three parts, enciphered withUmkehrwalze Doraand intercepted by the British on 11 March 1945, is shown. The successful recovery of the key of this message is described. Modern computer-based cryptanalysis is used to recover the wiring of the unknown “Uncle Dick,” which the British called this field-rewirable reflector. The attack is based on the known ciphertext and plaintext pair from the first part of the intercept. After recovery of the unknown reflector wiring and the daily key, the plaintext of the second part of the message is revealed. [ABSTRACT FROM PUBLISHER]

The Hagelin M-209 portable encryption device was used by the U.S. Army in World War II and the Korean War, as well as by other armies and in embassy settings. In this article, a fully automated, computerized known-plaintext attack is presented. It is based on hillclimbing and a novel fitness function: the aggregate displacement error. Performance evaluation shows that this attack is able to recover key settings for messages as short as 50 characters. To validate these results, several publicly available challenge messages were solved with this method, including a message with only 40 letters. [ABSTRACT FROM PUBLISHER]

This paper presents a method for constructing of the minimax class of perfect binary arrays with order N = 6. Maximum peak level of the two-dimensional periodic cross-correlation function between perfect binary arrays of minimax class has been evaluated. Power of the minimax class has been determined. Development of method is based on analysis of structural and correlation properties of thinned matrices. Paper proposes the method for single-channel and multi-channel cryptographic information transfer systems design. These systems are based on codes designed on the basis of minimax class of perfect binary arrays. Limits on the number of channels in multi-channel system determined. The method for overcoming of these limitations proposed. [ABSTRACT FROM AUTHOR]

Today, security is a prominent issue when any type of communication is being undertaken. Like traditional networks, supervisory control and data acquisition (SCADA) systems suffer from a number of vulnerabilities. Numerous end-to-end security mechanisms have been proposed for the resolution of SCADA-system security issues, but due to insecure real-time protocol use and the reliance upon open protocols during Internet-based communication, these SCADA systems can still be compromised by security challenges. This study reviews the security challenges and issues that are commonly raised during SCADA/protocol transmissions and proposes a secure distributed-network protocol version 3 (DNP3) design, and the implementation of the security solution using a cryptography mechanism. Due to the insecurities found within SCADA protocols, the new development consists of a DNP3 protocol that has been designed as a part of the SCADA system, and the cryptographically derived security is deployed within the application layer as a part of the DNP3 stack. [ABSTRACT FROM AUTHOR]

As a result of the continuously increasing amount of important data, the demand for information security increases daily. Steganographic techniques can play a considerable role in solving this issue, since they can hide the necessary data. Generally, audio and image files have been utilized as hiding media in this area. However, because of their limited capacity, these media limit the amount of hidden information. On the other hand, the capacity limit can be exceeded by applying steganography on video files. There are few studies on video steganography in the literature. In this study, a steganographic library, which is independent of medium and method, was developed for hiding information in audio, image, and video files by using various methods. Furthermore, distinctly from other studies, the lattice approach was proposed for this issue. In this approach, security was increased by using the image and audio domain of video together in the hiding process. In addition, we were able to hide the real-time data in a video taken from a webcam. Thus, the size of the produced video file could be set, according to the size of the secret file, with this model. Meanwhile, the possibility of detecting the existence of steganography by comparing to the original video was limited. The success of the hiding process was also evaluated with various steganalyses and noise measurement methods, and the results are presented and discussed in the relevant sections. [ABSTRACT FROM AUTHOR]

We present stego-texture, a unique texture synthesis method that allows users to deliver personalized messages with beautiful, decorative textures. Our approach was inspired by the success of recent work generating marbling textures using mathematical functions. We were able to transform an input image or a text message into an intricate texture by combining the seven basic, reversible functions provided in the system. Later, the input image or message could be recovered by reversing the process of these functions. During the design process, the parameters of operations were automatically recorded, encrypted and invisibly embedded into the final pattern to create a stego-texture. In this way, the receiver could extract the hidden message from the stego-texture without the need for extra information from the sender. To ensure that the delivered message is unnoticeably covered by the texture, we propose a new technique for automatically creating a background that is harmonious with the message based on a set of visual perception cues. [ABSTRACT FROM AUTHOR]

We study a method for key predistribution in a network of n users where pairwise keys are computed by hashing users' IDs along with secret information that has been (pre)distributed to the network users by a trusted entity. A communication graph G can be specified to indicate which pairs of users should be able to compute keys. We determine necessary and sufficient conditions for schemes of this type to be secure. We also consider the problem of minimizing the storage requirements of such a scheme; we are interested in the total storage as well as the maximum storage required by any user. Minimizing the total storage is NP-hard, whereas minimizing the maximum storage required by a user can be computed in polynomial time. [ABSTRACT FROM AUTHOR]

We analyze and present an attack scheme of the asymmetric optical cryptosystem proposed recently based on coherent superposition and equal modulus decomposition [Opt. Lett. 40, 475 (2015)]. We prove that the attacker can recover the original image with the ciphertext and public keys through the amplitude-phase retrieval algorithm by using two constraints. One constraint of the amplitude-phase retrieval algorithm is the public key and the other is obtained through the analysis of the cryptosystem. The simulation results demonstrate the feasibility of the attack method. [ABSTRACT FROM AUTHOR]

Finite field arithmetic operations have been traditionally used in different applications ranging from error control coding to cryptographic computations. Among these computations are normal basis multiplications and exponentiations which are utilized in efficient applications due to their advantageous characteristics and the fact that squaring (and subsequent powering by two) of elements can be obtained with no hardware complexity. In this paper, we present 2-D decomposition systolic-oriented algorithms to develop systolic structures for digit-level Gaussian normal basis multiplication and exponentiation over GF(2^m) . The proposed high-performance architectures are suitable for a number of applications, e.g., architectures for elliptic curve Diffie–Hellman key agreement scheme in cryptography. The results of the benchmark of efficiency, performance, and implementation metrics of such architectures through a 65-nm application-specific integrated circuit platform confirm high-performance structures for the multiplication and exponentiation architectures presented in this paper are suitable for high-speed architectures, including cryptographic applications. [ABSTRACT FROM PUBLISHER]

Data storage defense is an aggregate of problems, interlinked with the use of cryptographic program facilities of the different setting. For the decision of this task - using free of charge cross platform cryptographic TrueCrypt software with the opened source code, allows to make coding of information «on the fly». The analysis of TrueCrypt software possibilities is executed. The algorithm for defense of data storage with practical application TrueCrypt software is developed. The productivity comparative analysis of the personal computer with/out cryptographic TrueCrypt software is resulted. Actual absence of the productivity decline is showed. Independent audit considered cryptographic TrueCrypt software did not expose the greatest threats his vulnerability. Personal author's 10-years experience in exploitation TrueCrypt software for defense of data storage allows to assert a blamelessness, reliability and stability of it work. It's shown that cryptographic TrueCrypt software and its subsequent modifications, is the most effective measure, which allows preventing the losses of confidential information of users, placed on the personal computer and external data storage. [ABSTRACT FROM AUTHOR]

Information security is one of the most challenging problems in today's technological world. In order to secure the transmission of secret data over the public network (Internet), various schemes have been presented over the last decade. Steganography combined with cryptography, can be one of the best choices for solving this problem. This paper proposes a new steganographic method based on gray-level modification for true colour images using image transposition, secret key and cryptography. Both the secret key and secret information are initially encrypted using multiple encryption algorithms (bitxor operation, bits shuffling, and stego key-based encryption); these are, subsequently, hidden in the host image pixels. In addition, the input image is transposed before data hiding. Image transposition, bits shuffling, bitxoring, stego key-based encryption, and gray-level modification introduce five different security levels to the proposed scheme, making the data recovery extremely difficult for attackers. The proposed technique is evaluated by objective analysis using various image quality assessment metrics, producing promising results in terms of imperceptibility and security. Moreover, the high quality stego images and its minimal histogram changeability, also validate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Due to their unique physical properties, physically unclonable functions (PUF) have been proposed widely as versatile cryptographic primitives. It is desirable that silicon PUF circuits should be lightweight, i.e., have low-hardware resource requirements. However, it is also of primary importance that such demands of low hardware overhead should not compromise the security aspects of PUF circuits. In this paper, we develop two different mathematical attacks on previously proposed lightweight PUF circuits, namely composite PUF and the multibit output lightweight secure PUF (LSPUF). We show that independence of various components of composite PUF can be used to develop divide and conquer attacks which can be used to determine the responses to unknown challenges. We reduce the complexity of the attack using a machine learning-based modeling analysis. In addition, we elucidate a special property of the output network of LSPUF to show how such feature can be leveraged by an adversary to perform an intelligent model building attack. The theoretical inferences are validated through experimental results. More specifically, proposed attacks on composite PUF are validated using the challenge-response pairs (CRPs) from its field programmable gate array (FPGA) implementation, and attack on LSPUF is validated using the CRPs of both simulated and FPGA implemented LSPUF. [ABSTRACT FROM PUBLISHER]

We propose an efficient and effective methods to secure software implementations of cryptographic primitives on low-end embedded systems, against passive side channel attacks relying on the observation of power consumption or electro-magnetic emissions. The proposed approach exploits a modified LLVM compiler toolchain to automatically generate a secure binary characterized by a randomized execution flow. We improve the current state-of-the-art in dynamic executable code countermeasures removing the requirement of a writable code segment, and reducing the countermeasure overhead. Also, we provide a new method to refresh the random values employed in the share splitting approaches to lookup table protection. Finally, we devise an automated approach to protect spill actions onto the main memory, which are inserted by the compiler backend register allocator when there is a lack of available registers, thus, removing the need for manual assembly inspection. We report a validation of the performances of our approach on all the current ISO-standard block ciphers, employing an ARM Cortex-M4 based microcontroller as the validation platform. [ABSTRACT FROM PUBLISHER]

Side-channel attacks are one of the major concerns for security-enabled applications as they make use of information leaked by the physical implementation of the underlying cryptographic algorithm. Hence, reducing the side-channel leakage of the circuits realizing the cryptographic primitives is amongst the main goals of circuit designers. In this paper, we present a novel circuit concept, which decouples the main power supply from an internal power supply that is used to drive a single logic gate. The decoupling is done with the help of buffering capacitances integrated into semiconductor. We also introduce—compared to the previously known schemes—an improved decoupling circuit which reduces the crosstalk from the internal to the external power supply. The result of practical side-channel evaluation on a prototype chip fabricated in a 150nm CMOS technology shows a high potential of our proposed technique to reduce the side-channel leakages. [ABSTRACT FROM PUBLISHER]

This paper investigates a novel attack vector against cryptography realized on FPGAs, which poses a serious threat to real-world applications. We demonstrate how a targeted bitstream modification can seriously weaken cryptographic algorithms, which we show with the examples of AES and 3-DES. The attack is performed by modifying the FPGA bitstream that configures the hardware elements during initialization. Recently, it has been shown that cloning of FPGA designs is feasible, even if the bitstream is encrypted. However, due to its proprietary file format, a meaningful modification is challenging. While some previous work addressed bitstream reverse-engineering, so far it has not been evaluated how difficult it is to detect and modify cryptographic elements. We outline two possible practical attacks that have serious security implications. We target the S-boxes of block ciphers that can be implemented in look-up tables or stored as precomputed set of values in the memory of the FPGA. We demonstrate that it is possible to detect and apply meaningful changes to cryptographic elements inside an unknown, proprietary, and undocumented bitstream. Our proposed attack does not require any knowledge of the internal routing. Furthermore, we show how an AES key can be revealed within seconds. Finally, we discuss countermeasures that can raise the bar for an adversary to successfully perform this kind of attack. [ABSTRACT FROM PUBLISHER]

Auctions have a long history, having been recorded as early as 500 B.C. [Auction Theory, Academic Press, San Diego, USA, 2002]. Nowadays, electronic auctions have been a great success and are increasingly used in various applications, including high performance computing [Concurrency and Computation: Practice and Experience 14(13-15) (2002), 1507- 1542]. Many cryptographic protocols have been proposed to address the various security requirements of these electronic transactions, in particular to ensure privacy. Brandt [International Journal of Information Security 5 (2006), 201-216] developed a protocol that computes the winner using homomorphic operations on a distributed ElGamal encryption of the bids. He claimed that it ensures full privacy of the bidders, i.e. no information apart from the winner and the winning price is leaked. We first show that this protocol - when using malleable interactive zero-knowledge proofs - is vulnerable to attacks by dishonest bidders. Such bidders can manipulate the publicly available data in a way that allows the seller to deduce all participants' bids. We provide an efficient parallelized implementation of the protocol and the attack to show its practicality. Additionally we discuss some issues with verifiability as well as attacks on non-repudiation, fairness and the privacy of individual bidders exploiting authentication problems. [ABSTRACT FROM AUTHOR]

DNA cryptography is a novel field being taken up by the researcher community for research now days in order to have secure communication on a network. This technique is inspired from biological science, in which DNA is used as an information carrier from one generation to another. DNA cryptography is proposed for a secure end to end communication due to the vast parallelism and extra ordinary information density that are inherent in any DNA molecule. In this paper previous algorithm based on DNA cryptography is enhanced in terms of its security parameter by incurring feistel inspired structure in it. This adds some sort of confusion and diffusion, which makes it complex enough that it restricts the adversary to perform any kind of brute force attack. Encryption and decryption time is also compared on the basis of variable plaintext size. [ABSTRACT FROM PUBLISHER]

Exposure of private keys in cryptographic schemes leads to breakage of security of the scheme as a whole. To avoid the damage caused by key exposure problem, in this paper, we propose an efficient ID-Based Key-insulated Signature (IBKIS) scheme with batch verifications using bilinear pairings over elliptic curves. This scheme updates the signer's private keys from time to time. The proposed scheme is secure in the random oracle model with the assumption that the CDH problem is intractable. We compare the proposed scheme with related schemes. [ABSTRACT FROM PUBLISHER]

A child prodigy and Harvard University graduate turned serial killer, Theodore Kaczynski—now better known as the Unabomber—constructed elaborate cipher systems to encrypt his thoughts and emotions. His personal journals contain enciphered details of his life, his beliefs and feelings about society, and his crimes. This article introduces the Unabomber's cipher systems and through his use of these systems gives a brief glimpse into a fascinating mind that crossed the line between genius and madness. [ABSTRACT FROM PUBLISHER]

Pairings on elliptic curves are currently of great interest due to their applications in a number of cryptographic protocols such as identity-based encryption, group signatures, short signatures, and the tripartite Diffie-Hellman. Miller's algorithm is the most commonly used method of computing Tate pairing. Denominator elimination can improve Miller's algorithm when the embedding degree has the form 2i3j. However, if the embedding degree does not have the above form, how can the speed of Miller's algorithm be increased? In this article, the authors modified Miller's algorithm over Huff curves. It is about 20.38% faster than the original algorithm. [ABSTRACT FROM PUBLISHER]

A secure reconfigurable cryptographic co-processor supporting multiple algorithms of advanced encryption standard (AES), data encryption standard (DES), rivest cipher 6, and international data encryption algorithm is proposed using its own reconfigurable feature to resist side-channel attack (SCA). It is integrated into a system-on-chip and fabricated in 0.18~\boldsymbol \mu \textm CMOS process with 1.8 V supply voltage and 100 MHz max frequency. Several kinds of specific countermeasures are proposed to hide leakage information by utilizing idle reconfigurable processing elements to do dummy operations. Its advantages lie in its little impact on area and frequency as well as high flexibility after silicon that countermeasures can also be reconfigured. Furthermore, different protections including several kinds of global countermeasures and encryption flow related countermeasures can be stacked, thus the security level can be tuned by trading for some performance or power consumption. Experimental SCA attack results show that it resists simple power analysis and differential power analysis without revealing the subkey. For correlation-based electromagnetic analysis (EMA) of DES configuration, it increases 36\boldsymbol \times measure to disclosure when applied with partial countermeasures compared to unprotected DES. As to AES configuration with full countermeasures, it resists EMA with no sign to reveal the right subkey for up to 1.2 million electromagnetic traces. [ABSTRACT FROM PUBLISHER]

Embedded cryptographic devices are vulnerable to power analysis attacks. Threshold implementations (TIs) provide provable security against first-order power analysis attacks for hardware and software implementations. Like masking, the approach relies on secret sharing but it differs in the implementation of logic functions. While masking can fail to provide protection due to glitches in the circuit, TIs rely on few assumptions about the hardware and are fully compatible with standard design flows. We investigate two important properties of TIs in detail and point out interesting trade-offs between circuit area and randomness requirements. We propose two new TIs of AES that, starting from a common previously published implementation, illustrate possible trade-offs. We provide concrete ASIC implementation results for all three designs using the same library, and we evaluate the practical security of all three designs on the same FPGA platform. Our analysis allow us to directly compare the security provided by the different trade-offs, and to quantify the associated hardware cost. [ABSTRACT FROM PUBLISHER]

The use of the well known provably secure public-key cryptoscheme by Rabin is extended for the case of the deniable encryption. In the proposed new sender-deniable encryption scheme the cryptogram is computed as coe±cients of quadratic congruence, the roots of which are two simultaneously encrypted texts. One of the texts is a fake message and the other one is a ciphertext produced by public-key encryption of secret message. The proposed deniable encryption method produces a ciphertext that is computationally indistinguishable from the ciphertext produced by some probabilistic public-key encryption algorithm applied to the fake message. [ABSTRACT FROM AUTHOR]

Multiplicative linear secret sharing is a fundamental notion in the area of secure multiparty computation and, since recently, in the area of two-party cryptography as well. In a nutshell, this notion guarantees that the product of two secrets is obtained as a linear function of the vector consisting of the coordinatewise product of two respective share-vectors. This paper focuses on the following foundational question, which is novel to the best of our knowledge. Suppose we abandon the latter linearity condition and instead require that this product is obtained by some, not-necessarily-linear "product reconstruction function." Is the resulting notion equivalent to multiplicative linear secret sharing? We show the (perhaps somewhat counterintuitive) result that this relaxed notion is strictly more general. Concretely, fix a finite field 픽 q as the base field over which linear secret sharing is considered. Then we show there exists an (exotic) linear secret sharing scheme with an unbounded number of players n such that it has t-privacy with t = Ω(n) and such that it does admit a product reconstruction function, yet this function is necessarily nonlinear. In addition, we determine the minimum number of players for which those exotic schemes exist. Our proof is based on combinatorial arguments involving quadratic forms. It extends to similar separation results for important variations, such as strongly multiplicative secret sharing. [ABSTRACT FROM AUTHOR]

Security techniques like cryptography and authentication can fail to protect a network once a node is compromised. Hence, trust establishment continuously monitors and evaluates node behavior to detect malicious and compromised nodes. However, just like other security schemes, trust establishment is also vulnerable to attack. Moreover, malicious nodes might misbehave intelligently to trick trust establishment schemes. Unfortunately, attack-resistance and robustness issues with trust establishment schemes have not received much attention from the research community. Considering the vulnerability of trust establishment to different attacks and the unique features of sensor nodes in wireless sensor networks, we propose a lightweight and robust trust establishment scheme. The proposed trust scheme is lightweight thanks to a simple trust estimation method. The comprehensiveness and flexibility of the proposed trust estimation scheme make it robust against different types of attack and misbehavior. Performance evaluation under different types of misbehavior and on-off attacks shows that the detection rate of the proposed trust mechanism is higher and more stable compared to other trust mechanisms. [ABSTRACT FROM AUTHOR]