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The place of public key cryptography (PKC) in guaranteeing the security of wireless networks under human-centered IoT environments cannot be overemphasized. PKC uses the idea of paired keys that are mathematically dependent but independent in practice. In PKC, each communicating party needs the public key and the authorized digital certificate of the other party to achieve encryption and decryption. In this circumstance, a directory is required to store the public keys of the participating parties. However, the design of such a directory can be cost-prohibitive and time-consuming. Recently, identity-based encryption (IBE) schemes have been introduced to address the vast limitations of PKC schemes. In a typical IBE system, a third-party server can distribute the public credentials to all parties involved in the system. Thus, the private key can be harvested from the arbitrary public key. As a result, the sender could use the public key of the receiver to encrypt the message, and the receiver could use the extracted private key to decrypt the message. In order to improve systems security, new IBE schemes are solely desired. However, the complexity and cost of designing an entirely new IBE technique remain. In order to address this problem, this paper presents a provably secure IBE transformation model for PKC using conformable Chebyshev chaotic maps under the human-centered IoT environment. In particular, we offer a robust and secure IBE transformation model and provide extensive performance analysis and security proofs of the model. Finally, we demonstrate the superiority of the proposed IBE transformation model over the existing IBE schemes. Overall, results indicate that the proposed scheme posed excellent security capabilities compared to the preliminary IBE-based schemes.

Recent developments in quantum computing have shed light on the shortcomings of the conventional public cryptosystem. Even while Shor's algorithm cannot yet be implemented on quantum computers, it indicates that asymmetric key encryption will not be practicable or secure in the near future. The National Institute of Standards and Technology (NIST) has started looking for a post-quantum encryption algorithm that is resistant to the development of future quantum computers as a response to this security concern. The current focus is on standardizing asymmetric cryptography that should be impenetrable by a quantum computer. This has become increasingly important in recent years. Currently, the process of standardizing asymmetric cryptography is coming very close to being finished. This study evaluated the performance of two post-quantum cryptography (PQC) algorithms, both of which were selected as NIST fourth-round finalists. The research assessed the key generation, encapsulation, and decapsulation operations, providing insights into their efficiency and suitability for real-world applications. Further research and standardization efforts are required to enable secure and efficient post-quantum encryption. When selecting appropriate post-quantum encryption algorithms for specific applications, factors such as security levels, performance requirements, key sizes, and platform compatibility should be taken into account. This paper provides helpful insight for post-quantum cryptography researchers and practitioners, assisting in the decision-making process for selecting appropriate algorithms to protect confidential data in the age of quantum computing. [ABSTRACT FROM AUTHOR]

Random number generators are a key element for various applications, such as computer simulation, statistical sampling, and cryptography. They are used to generate/derive cryptographic keys and non-repeating values, e.g., for symmetric or public key cyphers. The strength of a data protection system against cyber attacks corresponds to the strength of the weakest point in the security chain. Therefore, from a mathematical point of view, the security chain can be compromised even if the strongest algorithm is implemented. In fact, if the system requires keys or other random values and the generation process shows a certain vulnerability, the security of the system itself can be compromised. In this article, we present the most reliable tools and methodologies and the main standardisation efforts in the field of computer security to assess the quality of random number generators and ensure that they can be applied to computer security applications by offering adequate security strength. We offer a comprehensive guide that can be used as a quick and practical reference by developers of random number generators of any type to evaluate the random bit streams generated by implemented modules and determine whether or not they can be used in cybersecurity applications. Finally, we also present some use cases to which we applied the presented approach. [ABSTRACT FROM AUTHOR]

Basic security requirements such as confidentiality, user authentication and data integrity, are assured by using public-key cryptography (PKC). In particular, public-key signature schemes provide non-repudiation, integrity of transmitted messages and authentication. The presence of a large scale quantum computer would be a real threat to break the most widely used public-key cryptographic algorithms in practice, RSA, DSA, ECDSA signature schemes and Diffie-Hellman key exchange. Thus, all security protocols and applications where these public-key cryptographic algorithms are used are vulnerable to quantum-computer attacks. There are five directions of cryptographic primitives secure against a quantum computer: multivariate quadratic equation-based, hash-based, lattice-based, code-based and supersingular isogeny-based cryptography. These primitives could serve as replacements for current public-key cryptographic algorithms to prepare for post-quantum era. It is important to prioritize the fields to be replaced by post-quantum cryptography (PQC) since it is hard to replace the currently deployed PKC with PQC at the same time. The fields directly connected to human life such as vehicular communications should be the primary targets of PQC applications. This survey is dedicated to providing guidelines for adapting the most suitable post-quantum candidates to the requirements of various devices and suggesting efficient and physically secure implementations that can be built into existing embedded applications as easily as traditional PKC. It focuses on the five types of post-quantum signature schemes and investigates their theoretical backgrounds, structures, state-of-the-art constructions and implementation aspects on various platforms raging from resource constrained IoT devices to powerful servers connected to the devices for secure communications in post-quantum era. It offers appropriate solutions to find tradeoffs between key sizes, signature lengths, performance, and security for practical applications. [ABSTRACT FROM AUTHOR]

Secret key leakage has become a security threat in computer systems, and it is crucial that cryptographic schemes should resist various leakage attacks, including the continuous leakage attacks. In the literature, some research progresses have been made in designing leakage resistant cryptographic primitives, but there are still some remaining issues unsolved, e.g. the upper bound of the permitted leakage is fixed. In actual applications, the leakage requirements may vary; thus, the leakage parameter with fixed size is not sufficient against various leakage attacks. In this paper, we introduce some novel idea of designing a continuous leakage-amplified public-key encryption scheme with security against chosen-ciphertext attacks. In our construction, the leakage parameter can have an arbitrary length, i.e. the length of the permitted leakage can be flexibly adjusted according to the specific leakage requirements. The security of our proposed scheme is formally proved based on the classic decisional Diffie–Hellman assumption. [ABSTRACT FROM AUTHOR]

A centralized public-key infrastructure (PKI) has revealed disadvantages to enterprise applications. This work presents a taxonomy of blockchain-based decentralized PKI schemes along with the prospective technologies for developing a robust PKI for vehicle-to-everything communications. [ABSTRACT FROM AUTHOR]

Encryption is the process of securing confidential data that bars a third party's access to the information.RSA encryption utilises the property of complexity classes wherein the problem of prime integer factorization lies inside the Non-Polynomial time (NP-Hard) class, which makes it impervious to classical computers. Since it is so hard to break even for a computer, it becomes important to do encryption for all the secure transactions. Although it lies outside the capabilities of traditional computing, the recent developments in the field of quantum computing can be utilised to break RSA Encryption. The approach involves mapping of qubits used in a quantum machine to a constraint satisfaction problem (CSP) and then using them to check for factors. This consists of the use of a Multiplicative Boolean circuit in which the qubits utilised by the machine replaces the variables. These Qubits are then mapped as per the gates involved, and the factorization problem is thus transformed into a CSP problem, through which, the factors can be easily found. Once known, these factors can be used to calculate the public and private keys effectively breaking the encryption security. We provide a novel approach to highlight the importance of developing Post-Quantum cryptography techniques for providing a secure channel of communication. [ABSTRACT FROM AUTHOR]

The advent of quantum computing threatens to break many classical cryptographic schemes, leading to innovations in public key cryptography that focus on post-quantum cryptography primitives and protocols resistant to quantum computing threats. Lattice-based cryptography is a promising post-quantum cryptography family, both in terms of foundational properties as well as in its application to both traditional and emerging security problems such as encryption, digital signature, key exchange, and homomorphic encryption. While such techniques provide guarantees, in theory, their realization on contemporary computing platforms requires careful design choices and tradeoffs to manage both the diversity of computing platforms (e.g., high-performance to resource constrained), as well as the agility for deployment in the face of emerging and changing standards. In this work, we survey trends in lattice-based cryptographic schemes, some recent fundamental proposals for the use of lattices in computer security, challenges for their implementation in software and hardware, and emerging needs for their adoption. The survey means to be informative about the math to allow the reader to focus on the mechanics of the computation ultimately needed for mapping schemes on existing hardware or synthesizing part or all of a scheme on special-purpose har dware. [ABSTRACT FROM AUTHOR]

Investigating the security pitfalls of cryptographic protocols is crucial to understand how to improve security. At ICCCS'17, Wu and Xu proposed an efficient smart-card-based password authentication scheme for cloud computing environments to cope with the vulnerabilities in Jiang et al.'s scheme. However, we reveal that Wu-Xu's scheme actually is subject to various security flaws, such as offline password guessing attack and replay attack. Besides security, user friendly is also another great concern. In 2017, Roy et al. found that in most previous two-factor schemes a user has to manage different credentials for different services and further suggested a user-friendly scheme which is claimed to be suitable for multiserver architecture and robust against various attacks. In this work, we show that Roy et al.'s scheme fails to achieve truly two-factor security and shows poor scalability. At FGCS'18, Amin et al. pointed out that most of existing two-factor schemes are either insecure or inefficient for mobile devices due to the use of public-key techniques and thus suggested an improved protocol by using only light-weight symmetric key techniques. Almost at the same time, Wei et al. also observed this issue and proposed a new scheme based on symmetric key techniques with formal security proofs in the random oracle model. Nevertheless, we point out that both Amin et al.'s and Wei et al.'s schemes cannot achieve the claimed security goals (including the most crucial goal of "truly two-factor security"). Our results invalidate any use of the scrutinized schemes for cloud computing environments. [ABSTRACT FROM AUTHOR]

Lossy trapdoor functions (LTFs) have already found various applications in cryptography with many priorities. But constructing leakage resilient (LR) CCA secure PKE schemes through this way received less attention. Existing works could only be proven secure in a weakened model due to the power of leakage attack. To address this problem, we introduce a new variant of ABO-LTF which is called branch hidden ABO-LTF (BHABO-LTF) in this paper. This primitive provides protection for the information of evaluated branches rather than lossy branches, which means even an adversary knows the information of the set of lossy branches, it can still not determine whether the output is evaluated on an injective or a lossy branch as long as the inversion key is kept secret. We observe that if this primitive has Chameleon property, we could present a generic construction of CCA secure PKE schemes. Due to the transparency of lossy branches of the primitive, we find that our construction can naturally be extended to accommodate leakage resilience. We give a generic construction with a realization of LR-BHABO-LTFs under the decisional composite residuosity assumption. This construction can be proved secure in a well-accepted security model rather than existing LTF-based ones in weak key-leakage model. Besides, without the need to hide the information of lossy branches, a Chameleon BHABO-LTF can be constructed by additively homomorphic CPA secure PKE alone. So our work can also be viewed as an interesting progress to give a construction of CCA secure PKE from additively homomorphic CPA secure PKE with certain properties as well as their LR counterparts, which has been a longstanding problem. [ABSTRACT FROM AUTHOR]

The security of multimedia content and personal privacy for big data has triggered widespread concern in the society. Fully homomorphic encryption (FHE), which can homomorphically compute arbitrary functions on the encrypted data without knowing the secret key, is valuable in protecting user's data security. However, most of the FHE schemes only take single-bit of ciphertext as the input, which makes the evaluation process complicated. In EUROCRYPT'2015, Ducas and Micciancio proposed an FHE scheme FHEW with the plaintext space , and gave an assumption of extending the plaintext space to . In this paper, we optimize the decryption algorithm of FHEW in bootstrapping, and propose an FHE scheme with large plaintext space . Firstly, we optimize the rounding function of the decryption algorithm in FHEW to the msdExtract algorithm, which can homomorphically extract the most significant digit of the plaintext. Secondly, we design the msdExtract algorithm by employing the homomorphic accumulator, and present the process of general bootstrapping. Finally, based on the msdExtract algorithm, we extend the plaintext space of our scheme to , comparing to in FHEW. The security of our scheme is based on the basic LWE scheme and FHEW. What's more, our scheme can perform the evaluation more conveniently with large plaintext space, and can be applied to more scenarios. [ABSTRACT FROM AUTHOR]

PGP public keys are relatively small binary data. Their hashes are used and also visualized for comparison and validation purposes. We pursue a direct, but previously unused approach. We produce colorful images of public keys and other binary data by generating drawing primitives from binary input. Optionally, we also include the hashes in the visualization. The visualization of raw data together with its hash provides a further security benefit. With it we can visually detect hash collisions. The primary focus of this paper is a direct visualization of public keys. We tune the transparency heuristics for better results. Our method visually detects key spoofing on real SHA1 collision data. [ABSTRACT FROM AUTHOR]

At Eurocrypt '02, Cramer and Shoup introduced the idea of public key encryption schemes with double decryption mechanism (DD-PKE) and at Asiacrypt '03, Bresson, Catalano and Pointcheval revisited the notion of DD-PKE. They proposed the first DD-PKE scheme (called BCP cryptosystem) over the group of quadratic residues. In this paper, we point out an attack against BCP cryptosystem and propose a secure variant constructed over the group of signed quadratic residues (SQR). [ABSTRACT FROM AUTHOR]

This paper describes a generalized tweakable blockcipher HPH (Hash-Permutation-Hash), which is based on a public random permutation P and a family of almost-XOR-universal hash functions H=HKK∈K as a tweak and key schedule, and defined as y = HPHK((t1, t2), x) = P(x ⊕ HK(t1)) ⊕ HK(t2), where K is a key randomly chosen from a key space K, (t1, t2) is a tweak chosen from a valid tweak space T, x is a plaintext, and y is a ciphertext. We prove that HPH is a secure strong tweakable pseudorandom permutation (STPRP) by using H-coefficients technique. Then we focus on the security of HPH against multi-key and related-key attacks. We prove that HPH achieves both multi-key STPRP security and related-key STPRP security. HPH can be extended to wide applications. It can be directly applied to authentication and authenticated encryption modes. We apply HPH to PMAC1 and OPP, provide an improved authentication mode HPMAC and a new authenticated encryption mode OPH, and prove that the two modes achieve single-key security, multi-key security, and related-key security. [ABSTRACT FROM AUTHOR]

Hierarchical identity-based encryption is an important extension from IBE and has found many applications in the network world. Private key revocation is a crucial requirement for any public key system. In this paper, we propose a novel revocation method for the hierarchical identity-based encryption. Existing revocable hierarchical identity-based encryption schemes have several disadvantages: the key update size increases logarithmically with the number of users in the system, the public information of key update received by each user is different and always related to the level of the identity hierarchy and the security proof of the revocable scheme is very complex. In our scheme, cryptographic accumulators are used to compress hierarchical levels and revoked users’ information into constant values. So we achieve almost constant size of private key update which is irrelevant with the user number in the system. Because of the compression of hierarchical information we can use simple dual system encryption techniques to prove our scheme to be fully secure under several common assumptions without resorting to complex nested dual system encryption techniques. [ABSTRACT FROM AUTHOR]

In typical applications of homomorphic encryption, the first step consists for Alice of encrypting some plaintext m under Bob’s public key pk and of sending the ciphertext c=HEpk(m) to some third-party evaluator Charlie. This paper specifically considers that first step, i.e., the problem of transmitting c as efficiently as possible from Alice to Charlie. As others suggested before, a form of compression is achieved using hybrid encryption. Given a symmetric encryption scheme E, Alice picks a random key k and sends a much smaller ciphertext c′=(HEpk(k),Ek(m)) that Charlie decompresses homomorphically into the original c using a decryption circuit CE-1. In this paper, we revisit that paradigm in light of its concrete implementation constraints, in particular E is chosen to be an additive IV-based stream cipher. We investigate the performances offered in this context by Trivium, which belongs to the eSTREAM portfolio, and we also propose a variant with 128-bit security: Kreyvium. We show that Trivium, whose security has been firmly established for over a decade, and the new variant Kreyvium has excellent performance. We also describe a second construction, based on exponentiation in binary fields, which is impractical but sets the lowest depth record to 8 for 128-bit security. [ABSTRACT FROM AUTHOR]

The ASASA construction is a new design scheme introduced at ASIACRYPT 2014 by Biryukov, Bouillaguet and Khovratovich. Its versatility was illustrated by building two public-key encryption schemes, a secret-key scheme, as well as super S-box subcomponents of a white-box scheme. However, one of the two public-key cryptosystems was recently broken at CRYPTO 2015 by Gilbert, Plût and Treger. As our main contribution, we propose a new algebraic key-recovery attack able to break at once the secret-key scheme as well as the remaining public-key scheme, in time complexity 263 and 239, respectively (the security parameter is 128 bits in both cases). Furthermore, we present a second attack of independent interest on the same public-key scheme, which heuristically reduces the problem of breaking the scheme to an LPN instance with tractable parameters. This allows key recovery in time complexity 256. Finally, as a side result, we outline a very efficient heuristic attack on the white-box scheme, which breaks instances claiming 64 bits of security under one minute on a laptop computer. [ABSTRACT FROM AUTHOR]

Securing user identity from data breach in a web server is one of the major concerns for the users of the web applications. Similarly, protecting user access pattern from unauthorized access should be taken seriously, because the potential threats such attacks may pose, are huge. However, these security measures should not be adopted at the expense of user experience and convenience. Nevertheless, any extra overhead in the form of security measures introduced in a distributed system results in significant performance declination. The target of a secured framework for a distributed system like web application should be a reasonable trade-off between security and user experience. Thus, in this work, we present a framework that ensures security for the user identity along with keeping the online activities of the users anonymous while ensuring scalability of the system. Our framework is designed in a scalable form that can work with other distributed architectures that provide security to user data and identities. To ensure all these measures, our proposal includes the implementation of Forward Secrecy using Diffie-Hellman Key exchange protocol where the server cannot remember a user's history after a session ends. In addition, we present our own mechanism to hide logical data sharing strategies to protect users against selective DoS attacks. Moreover, we implemented a modified version of bloom filter to safeguard user access pattern in a compromised server. Our proposed implementation of bloom filter also ensures that the scalability of distributed system is preserved even with little infrequent overhead in the server because of security measures proposed in this work. Finally, we implemented different modules of our framework using both Web Socket and Long Polling transport protocols and recorded the time required to perform various tasks. Web socket protocol took less time to perform each task than the long polling protocol, which is convincing enough to suggest that web socket performs better than long polling in the given scenarios. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the past, a large part of security requirements of wireless sensor networks (WSN) were fulfilled by symmetric cryptography systems. But, today by introduction of new needs in these networks and their security development, researchers of security and cryptography try to find new ways to increase efficiency and security of wireless sensor networks. Improving computational power of sensors used in wireless sensor networks made application of public key cryptography in WSN possible. Identity based cryptography is one important type of public key cryptography which using some bilinear functions called pairing functions was seriously applied. In this paper we will look at some researches done to find how to use pairings in wireless sensor networks. [ABSTRACT FROM AUTHOR]

Recently, much attention has been focused on designing provably secure cryptographic scheme in the presence of key leakage, and many constructions are proposed by cryptography researchers. However, most of them are researched in the bounded-leakage model, and cannot keep their claimed security in the continuous-leakage setting. It has been a research challenge to achieve the claimed security in continuous leakage setting. Also, for any polynomial time adversary, most of pre-existing constructions cannot ensure that their output is random in the leakage setting, and any adversary can get a certain amount of additional information on the private key from the output of cryptographic scheme. To obtain better performance (e.g., continuous leakage-resilience, etc.), a new construction of CCA2 secure continuous leakage-resilient certificateless public-key encryption scheme is proposed in this paper, and the scheme’s security is proved based on the hardness of the classical decisional Diffie–Hellman assumption. According to the results of analysis, we can get that our construction not only tolerates continuous leakage attacks on the private key through periodically update, but also enjoys better performances, such as the round leakage parameter has the constant size, and any polynomial time adversary are unable to get leakage on the private key from the corresponding ciphertext, etc. In particular, the striking advantage of our method is the key leakage ratio, which can achieve 3/4. Because these good performance features, our proposal may have some significant value in the practical applications. [ABSTRACT FROM AUTHOR]

Public key encryption with equality test (PKE-ET) is a public key encryption with an extra functionality, so-called ‘equality test’. An authorized third party can verify the equivalence between two ciphertexts encrypted under different public keys, while the decryption keeps unavailable. However, the privacy of most existing PKE-ET schemes drop to one-way security owing to the ‘equality test’ functionality. In this work, we propose a novel architecture called filtered equality test (FET), which ‘filtered’ denotes only few receiver-selected messages can be equality tested. In such model, we propose an equality test scheme, PKE-FET, which is the first one to be proved (somewhat) semantic secure. The concrete PKE-FET scheme and its rigorous security proof in the standard model are proposed. Furthermore, FET is also applied to construct a searchable encryption named PE-MKS, which is inherently proved semantic secure (so called the indistinguishability against chosen keyword attacks) in the standard model. [ABSTRACT FROM AUTHOR]

Supersingular isogeny graph–based cryptography has not yet been standardized, but the underlying hard problem has now been proposed as the basis for many cryptographic protocols. This motivates further investigation into the hardness of the underlying problem and the security of the proposed protocols. [ABSTRACT FROM PUBLISHER]

Code-based cryptography is one of the few mathematical techniques that enables the construction of public-key cryptosystems that are secure against an adversary equipped with a quantum computer. The McEliece public-key encryption scheme and its variants are candidates for a postquantum public-key encryption standard. [ABSTRACT FROM PUBLISHER]

The history of cryptography standards is reviewed, with a view to planning for the challenges, uncertainties, and strategies that the standardization of postquantum cryptography will entail. [ABSTRACT FROM PUBLISHER]

Typical digital technology users are often unaware of the cryptographic capabilities they utilize daily. The implications of quantum computers for various digital technologies and environments are discussed, and potential threat actor behaviors are explored. [ABSTRACT FROM PUBLISHER]

Quantum computers haven’t yet arrived, but a history of inertia in the wide-scale adoption of new cryptographic schemes means that standardization of postquantum signature schemes—particularly hash-based ones—is both timely and urgent. [ABSTRACT FROM PUBLISHER]

Cryptography provides confidentiality, integrity and availability. It is used to provide security and to communicate securely while the data is in transmission or at rest. Public key cryptography is used to implement these security mechanisms using secret keys for encryption and decryption. One of the most widely used public key cryptosystem is RSA. In this paper, implementation of the variants of RSA algorithm are performed and comparative analysis of these variants based on the time consumption for key generation, encryption and decryption process for different variants have been done. Result has been obtained and analysis is performed showing that security increases with increase in the key length. But it comes with a trade-off that it is more time consuming because of computational complexity of these algorithms. We implemented the variants of RSA algorithms namely ESRKGS and GRSA-AA algorithm. The comparative result is presented based on different parameters after which analysis is performed. [ABSTRACT FROM AUTHOR]

Modern vehicles are proficient in establishing a spontaneous connection over a wireless radio channel, synchronizing actions and information. Security infrastructure is most important in such a sensitive scope of vehicle communication for coordinating actions and avoiding accidents on the road. One of the first security issues that need to be established is authentication via IEEE 1609.2 security infrastructure. According to our preliminary work, vehicle owners are bound to preprocess a certificate from the certificate authority. The certificate carries vehicle static attributes (e.g., licence number, brand and color) certified together with the vehicle public key in a monolithic manner. Nevertheless, a malicious vehicle might clone the static attributes to impersonate a specific vehicle. Therefore, in this paper we consider a resource expensive attack scenario involving multiple malicious vehicles with identical visual static attributes. Apparently, dynamic attributes (e.g., location and direction) can uniquely define a vehicle and can be utilized to resolve the true identity of the vehicle. However, unlike static attributes, dynamic attributes cannot be signed by a trusted authority beforehand. We propose an approach to verify the coupling between non-certified dynamic attributes and certified static attributes on an auxiliary communication channel, for example, a modulated laser beam. Furthermore, we illustrate that the proposed approach can be used to facilitate the usage of existing authentication protocols such as NAXOS, in the new scope of ad-hoc vehicle networks. We use BAN logic to verify the security claims of the protocol against the passive and active interception. [ABSTRACT FROM AUTHOR]

Security is a significant issue for ad-hoc networks. Heterogeneous signcryption schemes proposed in recent years satisfy privacy and authentication of messages and reduce cost of computation and communication in a logical step. In this article, we present a new efficient heterogeneous signcryption scheme that shifts between the public key infrastructure (PKI) and the identity-based cryptosystem (IBC). The proposed scheme is suitable for broadcast communication conditions in which senders can signcrypt multiple messages for multiple receivers simultaneously in the ad-hoc networks. This scheme is proved to satisfy confidentiality and unforgeability on the basis of the assumptions of bilinear Diffie-Hellman problem (BDHP), q-Diffie-Hellman inversion problem (q-DHIP), q-bilinear Diffie-Hellman inversion problem (q-BDHIP), and computational Diffie-Hellman problem (CDHP) in the random oracle model. We discuss the efficiency of our scheme theoretically. In the efficiency analysis phase, we show that our scheme is practical and efficient. In the performance analysis phase, we present additional tests, data, and explanations to prove that our scheme can be applied in ad-hoc networks. Finally, we apply our scheme to a simulated ad-hoc network. [ABSTRACT FROM AUTHOR]

Public key cryptography is one of the most important fields in computer security. . It is a method of transferring private information and data through open network communication, so only the receiver who has the secret key can read the encrypted messages which might be documents, phone conversations, images or other form of data. To implement privacy simply by encrypting the information intended to remain secret can be achieved by using methods of Public key cryptography. The information must be scrambled, so that other users will not be able to access the actual information. In this study, we propose new public key cryptographic technique based on Suzuki 2- group. We demonstrated the security of proposed public key cryptographic technique in the chosen plaintext attack in the random oracle model. [ABSTRACT FROM AUTHOR]

The circular security of public key encryptions has been drawn great attentions in recent years. The relationship of notions between circular securities and standard ones such as chosen plaintext security (CPA-security) and chosen ciphertext security (CCA-security) deserve to be clarified. For any integer n > 0 and n ≠ 2, whether the notions of n-circular securities can be implied by that of their standard correspondences, such as CPA or CCA security in public key setting, has largely remained open. Koppula, Ramchen, and Waters in TCC'15 recently made a separation in CPA case by proposing a CPA secure scheme that is not n-circular secure based on the recent candidate constructions of indistinguishable obfuscation. In this work, we consider the CCA case. In particular, inspired by the indistinguishable-obfuscation-based construction of Koppula et al., we obtain the following results: We make a separation between the n-circular CCA security and CCA security for anyn>0. Specifically, we propose a hybrid encryption scheme that achieves the CCA security but fails even in the n-circular CPA security. Hence, that makes a separation between the CCA security and the n-circular CCA security (and even the n-circular CPA security)., By revising the previous construction, we also present a CCA secure (hybrid encryption) scheme, which allows an adversary to recover all secret keys when obtaining an encrypted key cycle. Hence, that implies that: if a key cycle arises in a system, then a passive adversary might be able to recover all secret keys even if CCA-secure encryptions are used., The results in this work, together with that of Koppula et al., confirm that notions of circular securities are stronger than their standard correspondences. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Ad-hoc networks are a new paradigm of wireless communication for mobile host's need the certification system allocated by the central authorities and this is done by PKI which secures the network. PKI schemes in an efficient way. Mobile ad hoc network (MANET) technology spreads widely in these days. It is suitable for environments that need on fly setup. A lot of challenges come with implementing these networks. The most sensitive challenge that MANET faces is the security issue. Traditional Public Key cryptography (PKC) and Identity based Cryptography (IBE) are slow and not suitable for these environments because of the nodes resources limitations. This paper is going to discuss the security of MANET using the PKI schemes in an efficient way. This solution provides a secure way for MANET nodes to authenticate each other and to secure data sent by each other, But PKI is having the overhead problems as large number of authentication messages transferred between nodes. In this research we have presented a new algorithm that will extend the drawbacks of PKI technique and make the network much secure and reliable for small and larger scale networks. Keys and certificates have to be issued to each node (trusted), neglecting malicious nodes on the track and finding the valid route to transfer the data, in other words we have to design the algorithm that store all the path in the server and locations of all the nodes, which changes their location dynamically. [ABSTRACT FROM AUTHOR]