Biblio

Secure hash functions are widely used in cryptographic algorithms to secure against diverse attacks. A one-way secure hash function is used in the various research fields to secure, for instance, blockchain. Notably, most of the hash functions provide security based on static parameters and publicly known operations. Consequently, it becomes easier to attack by the attackers because all parameters and operations are predefined. The publicly known parameters and predefined operations make the oracle regenerate the key even though it is a one-way secure hash function. Moreover, the sensitive data is mixed with the predefined constant where an oracle may find a way to discover the key. To address the above issues, we propose a novel one-way secure hash algorithm, OSHA for short, to protect sensitive data against attackers. OSHA depends on a pseudo-random number generator to generate a hash value. Particularly, OSHA mixes multiple pseudo-random numbers to produce a secure hash value. Furthermore, OSHA uses dynamic parameters, which is difficult for adversaries to guess. Unlike conventional secure hash algorithms, OSHA does not depend on fixed constants. It replaces the fixed constant with the pseudo-random numbers. Also, the input message is not mixed with the pseudo-random numbers; hence, there is no way to recover and reverse the process for the adversaries.

The extensive use of the internet and web-based applications spot the multiserver authentication as a significant component. The users can get their services after authenticating with the service provider by using similar registration records. Various protocol schemes are developed for multiserver authentication, but the existing schemes are not secure and often lead towards various vulnerabilities and different security issues. Recently, Zhao et al. put forward a proposal for smart card and user's password-based authentication protocol for the multiserver environment and showed that their proposed protocol is efficient and secure against various security attacks. This paper points out that Zhao et al.'s authentication scheme is susceptive to traceability as well as anonymity attacks. Thus, it is not feasible for the multiserver environment. Furthermore, in their scheme, it is observed that a user while authenticating does not send any information with any mention of specific server identity. Therefore, this paper proposes an enhanced, efficient and secure user authentication scheme for use in any multiserver environment. The formal security analysis and verification of the protocol is performed using state-of-the-art tool “ProVerif” yielding that the proposed scheme provides higher levels of security.

Internet of Things (IoT) have offered great opportunities for the growth of smart objects in the last decade. Smart devices are deployed in many fields such as smart cities, healthcare and agriculture. One of the applications of IoT is Wireless Sensor Networks (WSN) that require inexpensive and space-economic design for remote sensing and communication capabilities. This, unfortunately, lead to their inherent security vulnerabilities. Lightweight cryptography schemes are designed to counter many attacks in low-powered devices such as the IoT and WSN. These schemes can provide support for data encryption and key management while maintaining some level of efficiency. Most of these block ciphers provide good security. However, due to the complex cryptographic scheme's efficiency and optimisation is an issue. In this work, we focus on a new lightweight encryption scheme called the Klein block cipher. The algorithms of Klein block cipher are analysed for performance and security optimisations. A new algorithm which consists of 3-layer substitute box is proposed to reduce the need for resource consumption but maintain the security.

Lightweight ciphers are algorithms with low computational and spacial complexity. In the modern world of miniaturization, a lightweight cipher is used in constrained devices such as RFID tags, fire and security detectors, devices for wireless communications and other IoT devices. Stream ciphers are symmetric ciphers which encrypts the plain text bit stream with corresponding key stream to generate cipher text. Hence a stream cipher with low computational complexity and maximum security can be termed as a lightweight stream cipher. Many light weight stream ciphers are already existing. Each has its own vulnerabilities and spacial requirement. This paper has successfully developed, implemented, and analyzed a lightweight stream cipher - A4. Along with low computational cost, A4 also ensures paramount security and is less prone to the emerging cryptographic attacks.

Since the last few decades, several chaotic encryption techniques are reported by different researchers. Although the cryptanalysis of some techniques shows the feebler resistance of those algorithms against any weaker attackers. However, different hyper-chaotic based and DNA-coding based encrypting methods are introduced recently. Though, these methods are efficient against several attacks, but, increase complexity as well. On account of these drawbacks, we have proposed a novel technique of chaotic encryption of an image using the integer wavelet transform (IWT) and global bit scrambling (GBS). Here, the image is transformed and decomposed by IWT. Thereafter, a chaotic map is used in the encryption algorithm. A key-dependent bit scrambling (GBS) is introduced rather than pixel scrambling to make the encryption stronger. It enhances key dependency along with the increased resistance against intruder attacks. To check the fragility and dependability of the algorithm, a sufficient number of tests are done, which have given reassuring results. Some tests are done to check the similarity between the original and decrypted image to ensure the excellent outcome of the decryption algorithm. The outcomes of the proposed algorithm are compared with some recent works' outputs to demonstrate its eligibility.

To prevent unauthorized access to adversaries, strong authentication scheme is a vital security requirement in client-server inter-networking systems. These schemes must verify the legitimacy of such users in real-time environments and establish a dynamic session key fur subsequent communication. Of late, T. H. Chen and J. C. Huang proposed a two-factor authentication framework claiming that the scheme is secure against most of the existing attacks. However we have shown that Chen and Huang scheme have many critical weaknesses in real-time environments. The scheme is prone to man in the middle attack and information leakage attack. Furthermore, the scheme does not provide two essential security services such user anonymity and session key establishment. In this paper, we present an enhanced user participating authenticating scheme which overcomes all the weaknesses of Chen et al.'s scheme and provide most of the essential security features.

In this paper, we present the enhancement of a lightweight key-policy attribute-based encryption (KP-ABE) scheme designed for the Internet of Things (IoT). The KP-ABE scheme was claimed to achieve ciphertext indistinguishability under chosen-plaintext attack in the selective-set model but we show that the KP-ABE scheme is insecure even in the weaker security notion, namely, one-way encryption under the same attack and model. In particular, we show that an attacker can decrypt a ciphertext which does not satisfy the policy imposed on his decryption key. Subsequently, we propose an efficient fix to the KP-ABE scheme as well as extending it to be a hierarchical KP-ABE (H-KP-ABE) scheme that can support role delegation in IoT applications. An example of applying our H-KP-ABE on an IoT-connected healthcare system is given to highlight the benefit of the delegation feature. Lastly, using the NIST curves secp192k1 and secp256k1, we benchmark the fixed (hierarchical) KP-ABE scheme on an Android phone and the result shows that the scheme is still the fastest in the literature.

We consider a one-time digital signature scheme recently proposed by Persichetti and show that a successful key recovery attack can be mounted with limited complexity. The attack we propose exploits a single signature intercepted by the attacker, and relies on a statistical analysis performed over such a signature, followed by information set decoding. We assess the attack complexity and show that a full recovery of the secret key can be performed with a work factor that is far below the claimed security level. The efficiency of the attack is motivated by the sparsity of the signature, which leads to a significant information leakage about the secret key.

Outsourcing services to cloud server (CS) becomes popular in these years. However, the outsourced services often involve with sensitive activity and CS naturally becomes a target of varieties of attacks. Even worse, CS itself can misuse the outsourced services for illegal profit. Traditional online banking system also can make use of a cloud framework to provide economical and high-speed online services to the consumers, which makes the financial dealing easy and convenient. Most of the banking organizations provide services through passbook, ATM, mobile banking, electronic banking (e-banking) etc. Among these, the e-banking and mobile banking are more convenient and becomes essential. Therefore, it is critical to provide an efficient, reliable and more importantly, secure e-banking services to the consumers. The cloud environment is suitable paradigm to a new, small and medium scale banking organization as it eliminates the requirement for them to start with small resources and increase gradually as the service demand rises. However, security is one of the main concerns since it deals with many sensitive data of the valuable customers. In addition to this, the access of various data needs to be restricted to prevent any unauthorized transaction. Nagaraju et al. presented a framework to achieve reliability and security in public cloud based online banking using multi-factor authentication concept. Unfortunately, the login and authentication protocol of this framework is prone to impersonation attack. In this paper, we have revised the framework to avoid this attack.

The current paper proposes a method to combine the theoretical concepts of the parallel processing created by the DNA computing and GA environments, with the effectiveness novel mechanism of the distinction and discover of the cryptosystem keys. Three-level contributions to the current work, the first is the adoption of a final key sequence mechanism by the principle of interconnected sequence parts, the second to exploit the principle of the parallel that provides GA in the search for the counter value of the sequences of the challenge to the mechanism of the discrimination, the third, the most important and broadening the breaking of the cipher, is the harmony of the principle of the parallelism that has found via the DNA computing to discover the basic encryption key. The proposed method constructs a combined set of files includes binary sequences produced from substitution of the guess attributes of the binary equations system of the cryptosystem, as well as generating files that include all the prospects of the DNA strands for all successive cipher characters, the way to process these files to be obtained from the first character file, where extract a key sequence of each sequence from mentioned file and processed with the binary sequences that mentioned the counter produced from GA. The aim of the paper is exploitation and implementation the theoretical principles of the parallelism that providing via biological environment with the new sequences recognition mechanism in the cryptanalysis.

In this paper, We propose DNA sticker model based algorithm, a computability model, which is a simulation of the parallel computations using the Molecular computing as in Adelman's DNA computing experiment, it demonstrates how to use a sticker-based model to design a simple DNA-based algorithm for attacking a linear and a non-linear feedback shift register (FSR) based stream cipher. The algorithm first construct the TEST TUBE contains all overall solution space of memory complexes for the cipher and initials of registers via the sticker-based model. Then, with biological operations, separate and combine, we remove those which encode illegal plain and key stream from the TEST TUBE of memory complexes, the decision based on verifying a key stream bit this bit represented by output of LFSRs equation. The model anticipates two basic groups of single stranded DNA molecules in its representation one of a genetic bases and second of a bit string, It invests parallel search into the space of solutions through the possibilities of DNA computing and makes use of the method of cryptanalysis of algebraic code as a decision technique to accept the solution or not, and their operations are repeated until one solution or limited group of solutions is reached. The main advantages of the suggested algorithm are limited number of cipher characters, and finding one exact solution The present work concentrates on showing the applicability of DNA computing concepts as a powerful tool in breaking cryptographic systems.

With the development of wireless communication, the reliability and the security of data is very significant for the wireless communication. In this paper, a delayed feedback chaotic encryption algorithm based on polar codes is proposed. In order to protect encoding information, we make uses of wireless channels to extract binary keys. The extracted binary keys will be used as the initial value of chaotic system to produce chaotic sequences. Besides, we use the chain effects of delayed feedback, which increase the difficulty of cryptanalysis. The results of the theoretical analyses and simulations show that the algorithm could guarantee the security of data transmission without affecting reliability.

The paper presents a cryptanalysis of an enhanced sub-image encryption method recently proposed by Wang et al. in Optics and Lasers in Engineering 86(2016). Their paper shows that a parallel sub-image encryption method proposed by Mirzaei et al. in Nonlinear Dyn. 67(2012) could be attacked by chosen plaintext attack and proposed an enhanced sub-image encryption method claimed to completely resist the chosen plaintext attack. However, the enhanced sub-image encryption method also has some weakness, such as the key streams are independent with the plain-image. In this paper, one chosen plaintext attack type of cryptanalysis is presented for the enhanced sub-image encryption method and completely broken the enhanced sub-image encryption method. The experimental results indicate that the enhanced sub-image encryption method is weak against chosen plaintext attack and should be improved for practical application.

A key exchange protocol is an important primitive in the field of information and network security and is used to exchange a common secret key among various parties. A number of key exchange protocols exist in the literature and most of them are based on the Diffie-Hellman (DH) problem. But, these DH type protocols cannot resist to the modern computing technologies like quantum computing, grid computing etc. Therefore, a more powerful non-DH type key exchange protocol is required which could resist the quantum and exponential attacks. In the year 2013, Lei and Liao, thus proposed a lattice-based key exchange protocol. Their protocol was related to the NTRU-ENCRYPT and NTRU-SIGN and so, was referred as NTRU-KE. In this paper, we identify that NTRU-KE lacks the authentication mechanism and suffers from the man-in-the-middle (MITM) attack. This attack may lead to the forging the authenticated users and exchanging the wrong key.

We present attacks that use only the volume of responses to range queries to reconstruct databases. Our focus is on practical attacks that work for large-scale databases with many values and records, without requiring assumptions on the data or query distributions. Our work improves on the previous state-of-the-art due to Kellaris et al. (CCS 2016) in all of these dimensions. Our main attack targets reconstruction of database counts and involves a novel graph-theoretic approach. It generally succeeds when R , the number of records, exceeds \$N2/2\$, where N is the number of possible values in the database. For a uniform query distribution, we show that it requires volume leakage from only O(N2 łog N) queries (cf. O(N4łog N) in prior work). We present two ancillary attacks. The first identifies the value of a new item added to a database using the volume leakage from fresh queries, in the setting where the adversary knows or has previously recovered the database counts. The second shows how to efficiently recover the ranges involved in queries in an online fashion, given an auxiliary distribution describing the database. Our attacks are all backed with mathematical analyses and extensive simulations using real data.

Quantum information exchange computer emulator is presented, which takes into consideration imperfections of real quantum channel such as noise and attenuation resulting in the necessity to increase number of photons in the impulse. The Qt Creator C++ program package provides evaluation of the ability to detect unauthorized access as well as an amount of information intercepted by intruder.

Recently, Jung et al. [1] proposed a data access privilege scheme and claimed that their scheme addresses data and identity privacy as well as multi-authority, and provides data access privilege for attribute-based encryption. In this paper, we show that this scheme, and also its former and latest versions (i.e. [2] and [3] respectively) suffer from a number of weaknesses in terms of finegrained access control, users and authorities collusion attack, user authorization, and user anonymity protection. We then propose our new scheme that overcomes these shortcomings. We also prove the security of our scheme against user collusion attacks, authority collusion attacks and chosen plaintext attacks. Lastly, we show that the efficiency of our scheme is comparable with existing related schemes.

A strong designated verifier signature (SDVS) is a variation of traditional digital signatures, since it allows a signer to designate an intended receiver as the verifier rather than anyone. To do this, a signer must incorporate the verifier's public key with the signing procedure such that only the intended receiver could verify this signature with his/her private key. Such a signature further enables a designated verifier to simulate a computationally indistinguishable transcript intended for himself. Consequently, no one can identify the real signer's identity from a candidate signer and a designated verifier, which is referred to as the property of signer ambiguity. A strong notion of signer ambiguity states that no polynomial-time adversary can distinguish the real signer of a given SDVS that is not received by the designated verifier, even if the adversary has obtained the signer's private key. In 2013, Islam and Biswas proposed a provably secure certificateless strong designated verifier signature (CL-SDVS) scheme based on bilinear pairings. In this paper, we will demonstrate that their scheme fails to satisfy strong signer ambiguity and must assume a trusted private key generator (PKG). In other words, their CL-SDVS scheme is vulnerable to both key-compromise and malicious PKG attacks. Additionally, we present an improved variant to eliminate these weaknesses.

Cloud storage can provide outsourcing data services for both organizations and individuals. However, cloud storage still faces many challenges, e.g., public integrity auditing, the support of dynamic data, and low computational audit cost. To solve the problems, a number of techniques have been proposed. Recently, Tian et al. proposed a novel public auditing scheme for secure cloud storage based on a new data structure DHT. The authors claimed that their scheme was proven to be secure. Unfortunately, through our security analysis, we find that the scheme suffers from one attack and one security shortage. The attack is that an adversary can forge the data to destroy the correctness of files without being detected. The shortage of the scheme is that the updating operations for data blocks is vulnerable and easy to be modified. Finally, we give our countermeasures to remedy the security problems.

The chaotic system and cryptography have some common features. Due to the close relationship between chaotic system and cryptosystem, researchers try to combine the chaotic system with cryptosystem. In this study, security analysis of an encryption algorithm which aims to encrypt the data with ECG signals and chaotic functions was performed using the Logistic map in text encryption and Henon map in image encryption. In the proposed algorithm, text and image data can be encrypted at the same time. In addition, ECG signals are used to determine the initial conditions and control parameters of the chaotic functions used in the algorithm to personalize of the encryption algorithm. In this cryptanalysis study, the inadequacy of the mentioned process and the weaknesses of the proposed method have been determined. Encryption algorithm has not sufficient capacity to provide necessary security level of key space and secret key can be obtained with only one plaintext/ciphertext pair with chosen-plaintext attack.

π-Cipher is one of the twenty-nine candidates in the second round of the CAESAR competition for authenticated ciphers. π-Cipher uses a parallel sponge construction, based upon an ARX permutation. This work shows several state recovery attacks, on up to three rounds. These attacks use known values in the function's bitrate, combined with values found through exhaustive search, to retrieve the remaining values in the internal state. These attacks can break one round, for any variant of π-Cipher, in negligible time. They can also break two or three rounds much faster than exhaustive search on the key, for some variants. However, these attacks only work against version 1 of π-Cipher, due to the differences in the padding function for version 2.0. To fill this gap, this work also includes a one round attack against version 2.0, building upon the distinguisher present in the π-Cipher submission document.

Physical layer security for wireless communication is broadly considered as a promising approach to protect data confidentiality against eavesdroppers. However, despite its ample theoretical foundation, the transition to practical implementations of physical-layer security still lacks success. A close inspection of proven vulnerable physical-layer security designs reveals that the flaws are usually overlooked when the scheme is only evaluated against an inferior, single-antenna eavesdropper. Meanwhile, the attacks exposing vulnerabilities often lack theoretical justification. To reduce the gap between theory and practice, we posit that a physical-layer security scheme must be studied under multiple adversarial models to fully grasp its security strength. In this regard, we evaluate a specific physical-layer security scheme, i.e. orthogonal blinding, under multiple eavesdropper settings. We further propose a practical "ciphertext-only attack" that allows eavesdroppers to recover the original message by exploiting the low entropy fields in wireless packets. By means of simulation, we are able to reduce the symbol error rate at an eavesdropper below 1% using only the eavesdropper's receiving data and a general knowledge about the format of the wireless packets.

EPC Gen2 tags are working as international RFID standards for the use in the supply chain worldwide, such tags are computationally weak devices and unable to perform even basic symmetric-key cryptographic operations. For this reason, to implement robust and secure pseudo-random number generators (PRNG) is a challenging issue for low-cost Radio-frequency identification (RFID) tags. In this paper, we study the security of LFSR-based PRNG implemented on EPC Gen2 tags and exploit LFSR-based PRNG to provide a better constructions. We provide a cryptanalysis against the J3Gen which is LFSR-based PRNG and proposed by Sugei et al. [1], [2] for EPC Gen2 tags using distinguish attack and make observations on its input using NIST randomness test. We also test the PRNG in EPC Gen2 RFID Tags by using the NIST SP800-22. As a counter-measure, we propose two modified models based on the security analysis results. We show that our results perform better than J3Gen in terms of computational and statistical property.

The ownership transfer of RFID tag means a tagged product changes control over the supply chain. Recently, Doss et al. proposed two secure RFID tag ownership transfer (RFID-OT) protocols based on quadratic residues. However, we find that they are vulnerable to the desynchronization attack. The attack is probabilistic. As the parameters in the protocols are adopted, the successful probability is 93.75%. We also show that the use of the pseudonym of the tag h(TID) and the new secret key KTID are not feasible. In order to solve these problems, we propose the improved schemes. Security analysis shows that the new protocols can resist in the desynchronization attack and other attacks. By optimizing the performance of the new protocols, it is more practical and feasible in the large-scale deployment of RFID tags.

The Center for Strategic and International Studies estimates the annual cost from cyber crime to be more than \$400 billion. Most notable is the recent digital identity thefts that compromised millions of accounts. These attacks emphasize the security problems of using clonable static information. One possible solution is the use of a physical device known as a Physically Unclonable Function (PUF). PUFs can be used to create encryption keys, generate random numbers, or authenticate devices. While the concept shows promise, current PUF implementations are inherently problematic: inconsistent behavior, expensive, susceptible to modeling attacks, and permanent. Therefore, we propose a new solution by which an unclonable, dynamic digital identity is created between two communication endpoints such as mobile devices. This Physically Unclonable Digital ID (PUDID) is created by injecting a data scrambling PUF device at the data origin point that corresponds to a unique and matching descrambler/hardware authentication at the receiving end. This device is designed using macroscopic, intentional anomalies, making them inexpensive to produce. PUDID is resistant to cryptanalysis due to the separation of the challenge response pair and a series of hash functions. PUDID is also unique in that by combining the PUF device identity with a dynamic human identity, we can create true two-factor authentication. We also propose an alternative solution that eliminates the need for a PUF mechanism altogether by combining tamper resistant capabilities with a series of hash functions. This tamper resistant device, referred to as a Quasi-PUDID (Q-PUDID), modifies input data, using a black-box mechanism, in an unpredictable way. By mimicking PUF attributes, Q-PUDID is able to avoid traditional PUF challenges thereby providing high-performing physical identity assurance with or without a low performing PUF mechanism. Three different application scenarios with mobile devices for PUDID and Q-PUDI- have been analyzed to show their unique advantages over traditional PUFs and outline the potential for placement in a host of applications.