RedHAWK: Reducing HAWK digital signature stored signing keys

Unmanned aerial vehicle (UAV) technologies have a promising application prospect. It is necessary to use digital signature schemes to protect the integrity and authentication of messages in the UAV networks. According to the characteristics of UAV networks, digital signature schemes should solve the problems of digital certificate management and key escrow, guarantee the real-time performance of UAV executing commands, and ensure that only the designated verifier can verify the signature. Therefore, we proposed a certificateless designated verifier proxy signature (CLDVPS) scheme which meets the requirements. We proved our signature scheme is existentially unforgeable under an adaptive chosen message attack in the random oracle model and compared the efficiency of our signature scheme with other signature schemes. We implemented these signature schemes in jPBC to obtain the computing time and theoretically analyzed signature length of these signature schemes. The analysis results indicate that our CLDVPS scheme is more efficient than most of other related signature schemes on computation costs and also efficient on communication costs.

The impending threat of large scale quantum computers to traditional RSA and ECC-based public-key cryptographic schemes prompted NIST to initiate a global level standardization process for quantum-attack resistant cryptography, which is popularly known as Post-Quantum Cryptography (PQC). The NIST PQC process mainly focussed on standardization of Public Key Encryption (PKE) schemes, Key Encapsulation Mechanisms (KEM) and Digital Signature (DS) schemes. The process which started in 2017, is currently at the end of the third round when the first set of algorithms to be standardized were announced. NIST selected one (1) Public Key Encryption (PKE) and Key Encapsulation Mechanism (KEM) and three (3) Digital Signature (DS) schemes as the first standards for PQC. There are different categories of PQC, which base their security guarantees on different types of hard problems in mathematics. However, schemes which derive their security from problems based on geometric structures called as lattices have formed the majority category, with with maximum representation throughout the entire duration of the NIST PQC standardization process. This category of PQC is known as lattice-based cryptography. Three (3) out of the four (4) selected candidates for standardization belong to this category, owing to their good balance of security and efficiency. Thus, lattice-based cryptography becomes the main focus of our research. Among the various parameters that were used as criteria for standardization, such as theoretical post-quantum (PQ) security guarantees, implementation cost and performance, resistance against physical attacks such as Side-Channel Analysis (SCA) and Fault Injection Analysis (FIA) emerged as an important criteria for standardization in the final round of the NIST PQC process. This is especially critical given its potential wide-scale adoption in a wide-range of devices, and particularly in embedded devices to which an attacker can obtain unimpeded physical access to the device. In this respect, the main goal of our research is \emph{to advance the understanding of Side-Channel Analysis (SCA) and Fault-Injection Analysis (FIA) of lattice-based cryptography}. We lay particular focus on candidates for PKE, KEM and DS schemes that have been competing in the NIST PQC standardization process. This thesis is broadly divided into two parts - (1) Side-Channel Analysis (SCA) and (2) Fault-Injection Analysis (FIA). Side-Channel Analysis (SCA): In the first part of the thesis (Chapters 3-8), we focus exclusively on SCA of lattice-based cryptography. In this respect, we demonstrate that lattice-based PKE/KEMs contain inherent algorithmic features that make them susceptible to very simple side-channel attacks in a chosen-ciphertext setting. We demonstrate that an attacker can craft chosen-ciphertexts to magnify leakage about the secret key, to realize a side-channel based oracle which can be exploited to perform key recovery with very minimal knowledge about the implementation/target device. Moreover, we demonstrate that leakage from several operations can be easily exploited for key recovery and our attacks apply in a generic manner to six (6) LWE/LWR-based PKE/KEMs. We refer to these attacks as Side-Channel assisted Chosen Ciphertext attacks, and in short known as SCA assisted CCA. Fault-Injection Analysis (FIA): In the second part of the thesis (Chapters 9-12), we shift our focus to FIA of lattice-based schemes. We demonstrate that implementations of several lattice-based PKE/KEMs contain critical vulnerabilities that make them easily susceptible to fault-injection attacks. We show that algorithmic design choices as well as implementation techniques to achieve performance, can lead to single point of failures, that can be exploited for efficient FIA in both lattice-based PKE/KEMs as well as DS schemes. In a nutshell, our works have shown that side-channel attacks and fault-injection attacks form a potent and realistic threat against lattice-based schemes. We have identified that lattice-based schemes possess inherent algorithmic properties, that can be exploited by a side-channel or fault-injection attacker for practical attacks. Thus, our work stresses the need towards more research on development of efficient and secure countermeasures for practical and real-world security of lattice-based schemes.

In this paper, an effective scheme to resist copy attack based on digital images' signatures is proposed. In the DCT domain, the digital images' signature is obtained by use of ICA. Then imbed both the digital signature and a watermark into the image. The embedded digital signature can test whether the digital signature is copied illegally or not. The experiment results show that the digital signatures algorithm have the universality of resisting copy attack.


 
 
 History of Seal and Printing Cultures Implications of the four important Chinese inventions, the compass, gun powder, papermaking, and printing, have far-reaching significance for human civilisation. The Chinese seal is intimately related to printing. Seals have the practical function of duplicating impressions of words or patterns. This process shares a very similar concept to printing on a small scale. Printing originated from the function of seals for making duplicated impressions, and for this reason Wang believes that seals constitute the prototype of printing. Seals in Traditional Commere Seals in certain Asian countries, such as Taiwan and Japan, play a vital role similar to that played by signatures in Western society. Particularly, the Chinese seal has been an integral part of Chinese heritage and culture. Wong states that seals usually symbolise tokens of promise in Chinese society. Ancient seals in their various forms have played a major role in information systems, in terms of authority, authentication, identification, certified proof, and authenticity, and have also been used for tamper-proofing, impression duplication, and branding purposes. To illustrate, clay sealing has been applied to folded documents to detect when sealed documents have been exposed or tampered with. Interestingly, one of the features of digital signature technology is also designed to achieve this purpose. Wong records that when the commodity economy began to develop and business transactions became more frequent, seals were used to prove that particular goods had been certified by customs. Moreover, when the goods were subject to tax by the government, seals were applied to the goods to prove the levy paid. Seals continue to be used in Chinese society as personal identification and in business transactions, official and legal documents, administrative warrants and charters. Paper-based Contract Signing with Seal Certificates In Taiwan and Japan, in certain circumstances, when two parties wish to formalise a contract, the seals of the two parties must be affixed to the contract. As Figure 1 illustrates, seal certificates are required to be attached to the signed and sealed contract for authentication as well as the statement of intent of a voluntary agreement in Taiwan. Figure 1. Example of a contract attached with the seal certificates A person can have more than one seal; however, only one seal at a time is allowed to be registered with a jurisdictional registration authority. The purpose of seal registration is to prevent seal forgery and to prove the identity of the seal owner. Namely, the seal registration process aims to associate the identity of the seal owner with the seal owner’s nominated seal, through attestation by a jurisdictional registration authority. Upon confirmation of the seal registration, the registration authority issues a seal certificate with both the seals of the registration authority and the registration authority executive. Digital Signatures for Electronic Commerce Handwritten signatures and tangible ink seals are highly impractical within the electronic commerce environment. However, the shift towards electronic commerce by both the public and private sector is an inevitable trend. ‘Trust’ in electronic commerce is developed through the use of ‘digital signatures’ in conjunction with a trustworthy environment. In principle, digital signatures are designed to simulate the functions of handwritten signatures and traditional seals for the purposes of authentication, data integrity, and non-repudiation within the electronic commerce environment. Various forms of Public Key Infrastructure (PKI) are employed to ensure the reliability of using digital signatures so as to ensure the integrity of the message. PKI does not, however, contribute in any way to the signatory’s ability to verify and approve the content of an electronic document prior to the affixation of his/her digital signature. Shortcomings of Digital Signature Scheme One of the primary problems with existing digital signatures is that a digital signature does not ’feel’ like, or resemble, a traditional seal or signature to the human observer; it does not have a recognisably individual or aesthetic quality. Historically, the authenticity of documents has always been verified by visual examination of the document. Often in legal proceedings, examination of both the affixed signature or seal as an integral part of the document will occur, as well as the detection of any possible modifications to the document. Yet, the current digital signature regime overlooks the importance of this sense of visualisation. Currently, digital signatures, such as the OpenPGP (Pretty Good Privacy) digital signature, are appended to an electronic document as a long, incomprehensible string of arbitrary characters. As shown in Figure 2, this offers no sense of identity or ownership by simple visual inspection. Figure 2. Example of a PGP signature To add to this confusion for the user, a digital signature will be different each time the user applies it. The usual digital signature is formed as an amalgam of the contents of the digital document and the user’s private key, meaning that a digital signature attached to an electronic document will vary with each document. This again represents a departure from the traditional use of the term ‘signature’. A digital signature application generates its output by firstly applying a hash algorithm over the contents of the digital document and then encrypting that hash output value using the user’s private cryptographic key of the normal dual-key pair provided by the Public Key cryptography systems. Therefore, digital signatures are not like traditional signatures which an individual can identify as being uniquely theirs, or as a recognisable identity attributable to an individual entity. New Visualised Digital Signature Scheme Liu et al. have developed the visualised digital signature scheme to enhance existing digital signature schemes through visualisation; namely, this scheme makes the intangible digital signature virtually tangible. Liu et al.’s work employs the visualised digital signature scheme with the aim of developing visualised signing and verification in electronic situations. The visualised digital signature scheme is sustained by the digital certificate containing both the certificate issuer’s and potential signer’s seal images. This thereby facilitates verification of a signer’s seal by reference to the appropriate certificate. The mechanism of ensuring the integrity and authenticity of seal images is to incorporate the signer’s seal image into an X.509 v3 certificate, as outlined in RFC 3280. Thus, visualised digital signature applications will be able to accept the visualised digital certificate for use. The data structure format of the visualised digital certificate is detailed in Liu. The visualised signing and verification processes are intended to simulate traditional signing techniques incorporating visualisation. When the signer is signing the document, the user interface of the electronic contracting application should allow the signer to insert the seal from the seal image file location into the document. After the seal image object is embedded in the document, the document is referred to as a ’visually sealed’ document. The sealed document is ready to be submitted to the digital signing process, to be transmitted with the signer’s digital certificate to the other party for verification. The visualised signature verification process is analogous to the traditional, sealed paper-based document with the seal certificate attached for verification. In history, documents have always required visual stimulus for verification, which highlights the need for visual stimulus evidence to rapidly facilitate verification. The user interface of the electronic contracting application should display the visually sealed document together with the associated digital certificate for human verification. The verifier immediately perceives the claimed signer’s seal on the document, particularly when the signer’s seal is recognisable to the verifier. This would be the case particularity where regular business transactions between parties occur. Significantly, having both the issuing CA’s and the signer’s seal images on the digital certificate instils confidence that the signer’s public key is attested to by the CA, as shown in Figure 3. This is unlike the current digital signature verification process which presents long, meaningless strings to the verifier. Figure 3. Example of a new digital certificate presentation Conclusions Seals have a long history accompanying the civilisation of mankind. In particular, certain business documents and government communities within seal-culture societies still require the imprints of the participating entities. Inevitably, the use of modern technologies will replace traditional seals and handwritten signatures. Many involved in implementing electronic government services and electronic commerce care little about the absence of imprints and/or signatures; however, there is concern that the population may experience difficulty in adapting to a new electronic commerce system where traditional practices have become obsolete. The purpose of the visualised digital signature scheme is to explore enhancements to existing digital signature schemes through the integration of culturally relevant features. This article highlights the experience of the use and development of Chinese seals, particularly in visualised seals used in a recognition process. Importantly, seals in their various forms have played a major role in information systems for thousands of years. In the advent of the electronic commerce, seal cultures still remain in the d

This article has attempted to understand the nature, meaning and scope of 'digital signature'. In turn, this article has also focused on the mechanism of affixing the 'digital signature' to electronic record. Signature signify authentication, verification and non-repudiation, but in electronic environment this mechanism happens in altogether different sense as compare to paper-based world because paper-based and paper-less world are different in its context and contents. The attempt is to understand the effect and impact of 'digital signature' in the cyberspace, its techno-legal effect and system if issuing, granting and maintaining the 'Digital Signature' in India. The limitation of this article is the legal system it focused upon, i.e. Indian Legal system. This article has understand the effect and impact of 'digital signature' in general sense, but keeping the Information Technology Act, 2000 [Indian piece of legislation dealing with Information Technology], thus context different to that effect.

To mitigate the damage of secret key exposure, key updating signature schemes can be used such as a key-insulated signature scheme and an intrusion-resilient signature scheme. We propose efficient key updating signature schemes based on a secure identity-based signature (IBS) scheme. KUS-SKI is a strong (N-1, N) key-insulated signature scheme with random-access key updates, and KUS-IR is a Type (I) intrusion-resilient signature scheme. We also provide an equivalence theorem between a secure identity-based signature scheme and a strong (N-1, N) key-insulated signature scheme with random-access key up-dates.

This article examines digital signature as a critical security measure for authentication and verification in electronic transactions, distinguishing them from simpler e-signatures by their use of advanced cryptographic techniques. Digital signature leverage asymmetric cryptography to provide higher security, with various standardised algorithms, such as the Digital Signature Algorithm (DSA) and Rivest- Shamir-Adleman (RSA), forming the foundation of secure systems today. The paper outlines the evolution of digital and electronic signature, from early telegraph-based approvals to the modern applications that facilitate secure digital contracts and communications. Key digital signature algorithms are analysed in detail, highlighting their strengths and weaknesses, including RSA, DSA, Elliptic Curve Digital Signature Algorithm (ECDSA), and Edwards-Curve Digital Signature Algorithm (EdDSA). Additionally, the article addresses the technical and implementation challenges of digital signature algorithms, such as high computational demands, complexities in key management, and difficulties in secure implementation. It concludes with an exploration of future trends, such as the development of efficient and quantum-resistant algorithms, improvements in cryptographic hardware, and new strategies to simplify secure key management. This comprehensive overview provides insights into both current digital signature practices and emerging solutions poised to enhance security and efficiency in an evolving digital landscape.

Digital signatures are the basis for identifying who sends file identities in modern society today. Digital signatures are a way to provide integrity and reliability for digital data signatures. Signatures use a set of principles and parameters that allow a computer to verify the identity and authentication of data. There are three algorithms for digital signature generation in the DSS. The first one is the RSA, the second is the ElGamal algorithm, and the third is the elliptic curve digital signature algorithm (ECDSA). This paper discusses the cryptography including different types of digital signatures based on the key type and some algorithms of digital signature, RSA, ElGamal, and ECDSA.

Inefficiencies in the clinical trial infrastructure result in protracted trial completion timelines, physician-investigator turnover, and a shrinking skilled labor force and present obstacles to research participation. Taken together, these barriers hinder scientific progress. Technological solutions to improve clinical trial efficiency have emerged, yet adoption remains slow because of concerns with cost, regulatory compliance, and implementation. A prospective pilot study that compared regulatory-compliant digital and traditional wet ink paper signatures was conducted over a 6.5-month period in a hospital-based health system. Staff time and effort, error rate, costs, and time to completion were measured. Wilcoxon rank sum tests were used to compare staff time and time to completion. A value analysis was conducted. A survey was administered to measure user satisfaction. There where 96 participants (47 digital, 49 paper), 132 studies included (31 digital, 101 paper), and 265 documents processed (156 digital, 109 paper). A moderate reduction in staff time required to prepare documents for signature was observed (P < .0001). Error rates were reported in 5.1% of digital and 2.8% of paper documents, but this difference was not significant. Discrepancies requiring revisions included incomplete mandatory fields, inaccurate information submitted, and technical issues. A value analysis demonstrated a 19% labor savings with the use of digital signatures. Survey response rate was 57.4% (n = 27). Most participants (85.2%) preferred digital signatures. The time to complete documents was faster with digital signatures compared with paper (P = .0241). The use of digital signatures resulted in a decrease in document completion time and regulatory burden as represented by staff hours. Additional cost and time savings and information liquidity could be realized by integrating digital signatures and electronic document management systems.

Based an identity-based signature scheme, we givea certificateless signature scheme. And then we propose a certificateless blind signature (CLBS) scheme in this paper. This schemeis more efficient than those of previous schemes by pre-computing the pairing e (P, P)=g. Based on CL-PKC, it eliminates theusing of certificates in the signature scheme with respect to thetraditional public key cryptography (PKC) and solves key escrowproblems in ID-based signature schemes. Meanwhile it retains themerits of BS schemes. The proposed CLBS scheme is existentialunforgeable in the random oracle model under the intractabilityof the q-Strong Diffie-Hellman problem.

This paper proposes the first code-based quantum immune sequential aggregate signature (SAS) scheme and proves the security of the proposed scheme in the random oracle model. Aggregate signature (AS) schemes and sequential aggregate signature schemes allow a group of potential signers to sign different messages respectively, and all the signatures of those users on those messages can be aggregated into a single signature such that the size of the aggregate signature is much smaller than the total size of all individual signatures. Because of the aggregation of many signatures into a single short signature, AS and SAS schemes can reduce bandwidth and save storage; moreover, when a SAS is verified, not only the valid but also the order in which each signer signed can be verified. AS and SAS schemes can be applied to traffic control, banking transaction and military applications. Most of the existing AS and SAS schemes are based either on pairing or Rivest–Shamir–Adleman (RSA), and hence, can be broken by Shor’s quantum algorithm for Integer Factoring Problem (IFP) and Discrete Logarithm Problem (DLP). There are no quantum algorithms to solve syndrome decoding problems. Hence, code-based cryptography is seen as one of the promising candidates for post-quantum cryptography. This paper shows how to construct quantum immune sequential aggregate signatures based on coding theory. Specifically, we construct our scheme with the first code based signature scheme proposed by Courtois, Finiasz and Sendrier (CFS). Compared to the CFS signature scheme without aggregation, the proposed sequential aggregate signature scheme can save about 90% storage when the number of signers is asymptotically large.

Like any other language, sign language is, among other things, guided by phonological principles involving several parameters combining in space to form lexical signs. According to Klima and Bellugi (1979), a simple lexical sign is essentially a simultaneous occurrence of a particular value of each of the several parameters. These parameters occur within a constrained signing space in combination with each other. William Stokoe (1960) equated phonology in oral language to what he termed cherology in sign language. However, most sign linguists prefer to use the term phonology. In oral language, phonology is the study of sounds, but in sign language, it is concerned with the parameters that make sign language a systematic and intelligible language system. One basic difference between oral and sign language is that in oral language we use words while in sign language we use signs. The other important difference is that while oral language is produced in the oral cavity using articulatory organs such as the mouth, sign language is produced in space using mostly the hands. Yet the structural difference is that while a phoneme in oral language is the basic unit of a word a chereme in sign language is the basic unit of a sign. In oral language words are organized sequentially while the signs in sign language are organized as a combination of simultaneously occurring components derived from several spatial dimensions. The purpose of this paper is to examine the parameters that characterize sign language and to demonstrate the formation, vocabulary and organization of signs. The paper demonstrates how signs are executed in space. The paper addresses four major phonological (cherological) parameters of sign language, namely hand configuration (hand shape), place of articulation (location / position), movement and orientation. Major parameters save to distinguish very large classes of signs. In addition the paper articulates how these parameters combine to formulate meaningful signs within the constrained signing space. From the analysis, the author concludes that the phonology of sign language is highly complex and is resident in space as a function of the hand acting as a highly articulatory linguistic organ.

Watermarking is largely used for copyright protection and fast search of images in databases. Another method for securely identifying images is to use hash functions. Digital signature standard, used in cryptosystem to dispute authentication documents, is based on hash functions. A digital signature is a bit stream dependent on key and content of document. For each document, the digital signature algorithm provides a unique output bit stream. In order to be efficient in images, the digital signature should be different if and only if the image content, and not the input bit stream, is different. Our new method is a one-way function for images. Using the radon transform and principal component analysis, we extract characteristics robust against geometrical transformation (rotation and scaling) and image processing attacks (compression, filtering, blurring).

ABSTRACTA signature scheme is one of the important primitives in modern cryptography, which may offer functionalities of user identification, non‐repudiation, and message authentication. With the advent of identity (ID)‐based public key systems with bilinear pairings defined on elliptic curves, many ID‐based signature schemes have been proposed. Like certificate‐based public key systems, any ID‐based public key system must provide a revocation method to revoke misbehaving users. There was little work on studying the revocation problem of ID‐based public key systems, and no ID‐based signature scheme deals with how to revoke the signing ability of misbehaving users. Quite recently, Tseng and Tsai presented a practical revocation mechanism using a public channel for ID‐based public key systems. In this paper, we adopt Tseng and Tsai's revocation concept to define the new framework and security notions of revocable ID‐based signature (RIBS) scheme and propose the first RIBS scheme in the standard model. Under the computational Diffie–Hellman assumption, we demonstrate that the proposed RIBS scheme is provably secure while remaining efficient for signing and verification as compared with previously proposed ID‐based signature schemes. Copyright © 2013 John Wiley &amp; Sons, Ltd.

Dynamic construction of signature files based on frame sliced approach