Key Holder Research Articles

On desynchronised multivariate algorithms of El Gamal type for stable semigroups of affine Cremona group

Families of stable cyclic groups of nonlinear polynomial transformations of affine spaces Kn over general commutative ring K of increasing with n order can be used in the key exchange protocols and related to them El Gamal multivariate cryptosystems. To use high degree of noncommutativity of affine Cremona group correspondents have to modify multivariate El Gamal algorithm via the usage of conjugations for two polynomials of kind gk and g−1 given by key holder (Alice) or giving them as elements of different transformation groups. The idea of hidden tame homomorphism and comlexity of decomposition of polynomial transwormation into word of elements of Cremona semigroup can be used. We suggest usage of new explicit constructions of infinite families of large stable subsemigroups of affine Cremona group of bounded degree as instruments of multivariate key exchange protocols. Recent results on generation of families of stable transformations of small degree and density via technique of symbolic walks on algebraic graphs are observed. Some of them used for the implementation of schemes as above with feasible computational complexity. We consider an example of a new implemented quadratic multivariate cryptosystem based on the above mentioned ideas.

Constrained Pseudorandom Functions for Turing Machines Revisited: How to Achieve Verifiability and Key Delegation

Constrained pseudorandom functions (CPRF) are an enriched variant of traditional pseudorandom functions (PRF)—a fundamental tool of modern cryptography. A CPRF enables a master PRF key holder to issue constrained keys corresponding to specific constraint predicates over the input domain. A constrained key can be used to evaluate the PRF on inputs accepted by the associated constraint predicate, while the PRF outputs on the rest of the inputs still remain computationally indistinguishable from uniformly random values. A constrained verifiable pseudorandom function (CVPRF) enhances a CPRF by adding a non-interactive public verification mechanism for checking the correctness of PRF evaluations. On the other hand, a delegatable constrained pseudorandom function (DCPRF) augments a CPRF with the ability to empower constrained key holders to delegate further constrained keys that allow PRF evaluations on inputs accepted by more restricted constraint predicates compared to ones embedded in their own constrained keys. Until recently, all the proposed constructions of CPRFs and their extensions (i) either could handle constraint predicates representable as circuits or (ii) were based on risky knowledge-type assumptions. In EUROCRYPT 2016, Deshpande et al. presented a CPRF supporting constraint predicates realizable by Turing machines (TM) based on indistinguishability obfuscation and injective pseudorandom generators. Their construction was claimed to be selectively secure. The first contribution of this paper is demonstrating that their claim is not valid. In fact, their CPRF construction can actually be proven secure not in the selective model, rather in a significantly weaker one where the adversary is completely static. We then modify their construction with innovative techniques so as to make the resulting CPRF selectively secure. Towards our goal, we suitably redesign the security proof as well. Most significantly, our modification does not involve any additional heavy duty cryptographic tool. Next, employing only standard public key encryption, we extend our improved CPRF construction to present the first ever CVPRF and DCPRF constructions that can handle constraints expressible as TMs.

Provably secure public-key encryption with conjunctive and subset keyword search

Public-key encryption with keyword search (PEKS) schemes enable public key holders to encrypt documents, while the secret key holder is able to generate queries for the encrypted data. In this paper, we present two PEKS schemes with extended functionalities. The first proposed scheme supports conjunctive queries. That is, it enables searching for encrypted documents containing a chosen list of keywords. We prove the computational consistency of our scheme, and we prove security under the asymmetric DBDH assumption. We show that it improves previous related schemes in terms of efficiency and in terms of index and trapdoor size. The second proposed scheme supports subset queries and some more general predicates. We prove the computational consistency of our scheme, and we prove our scheme secure under the p-BDHI assumption. We show that it improves previous related schemes in terms of efficiency and expressiveness. Moreover, unlike previous related schemes, it admits an arbitrary keyword space.

IPTEKS BAGI KEWIRAUSAHAAN (IbK) DI UNIVERSITAS MUHAMMADIYAH MAKASSAR (Peningkatan Kualitas Produk Tenan Melalui Pelatihan Ibk)

Science and Technology for Entrepreneurship (IbK) at the University of Muhammadiyah Makassar aims to improve the knowledge and skills of students who have started pioneering a product as a forerunner of independent business through the Student Creativity Program (PKM), and alumni are starting a new business (entrepreneurship), creating new entrepreneurs independently based science and technology and creating an entrepreneurial training methods suitable for the tenant. IbK activities take place during the first three years to build as many as 20 tenants consisting of the students who have EnterpreneurshipStudent Creativity Program (PKM-K) active students and alumni PKM-K, and, of the 20 tenants that have generated new independent entrepreneurs as many as five (5); among others: (1) The business of Fermented Milk (for health and cosmetics), (2) Shoes Sabbe / Silk Bugis, (3) Crackers Cassava and Banana, (4) Shredded Chilli, (5) Pin and Keychain. Specific targets to be achieved through IBK activities are spawned at least 5 participants IBK become new entrepreneurs based independent science and technology, at least 80% of participants prospective entrepreneurs first year to new entrepreneurs. Training Methods entrepreneurial knowledge in the form of lectures, training to improve product quality and improved packaging tenant.The Results of IbK in the first year of activities, namely; Enterprises of fruit and vegetable fermentation, Souvenir glass bamboo, Flowers Products Terrarium, fish fry and Miniature Boat Pinisi. Increasing the quantity and quality of production of the tenants have pushed their motivation to be more diligent in terms of marketing their products. There are two ways that do marketing tenanare included in the category of an Independent ie depending on the type of production the tenants, such as for the production of fermented milk and pin / key holder by way of order. As for the tenants who produce; Cassava crackers and bananas, chili, as well as silk shoes / sabbe consignment Keywords: Training, self-employment, production, marketing

Enhancing the economic value and consumer preferences of commercial mondol stingray (Himantura gerardi) leather creative products

The research objectives were to design, assess the economic value and consumer preference level of stingray leather products. The research method included a product design, analysis of economic value and consumer preferences. Mondol stingray (Himantura gerardi) leather, with a length of 50 cm and width of 30 cm, were processed into ID card wallet, man and women’s wallet and key holder. The number of respondents involved to analyze the preference level is 75 respondents (students, lecturers and employees of Universitas Gadjah Mada). Indicators of consumer preferences were model, color, price and purchasing power. The price of ID card wallet is Rp. 450,000; women wallet is Rp. 650,000 and a key holder is Rp. 300,000. Consumer preferences on ID card wallet were as follow: 84 % stated very interesting model; 83 % stated very interesting color; 61 % stated cheap and 53 % had enough. Consumer preferences of women’s wallet were as follow: 81 % stated very interesting model; 84 % stated very interesting color; 56 % stated cheap and 57 % had enough. Consumer preferences on key holder were as follow: 49 % stated interesting model; 72 % stated very interesting color; 61 % stated cheap and 57 % had enough.

On the Families of Stable Multivariate Transformations of Large Order and Their Cryptographical Applications

Abstract Families of stable cyclic groups of nonlinear polynomial transformations of affine spaces Kn over general commutative ring K of with n increasing order can be used in the key exchange protocols and El Gamal multivariate cryptosystems related to them. We suggest to use high degree of noncommutativity of affine Cremona group and modify multivariate El Gamal algorithm via conjugations of two polynomials of kind gk and g−1 given by key holder (Alice) or giving them as elements of different transformation groups. Recent results on the existence of families of stable transformations of prescribed degree and density and exponential order over finite fields can be used for the implementation of schemes as above with feasible computational complexity.

Establishing secure and anonymous communication channel: KEM/DEM-based construction and its implementation

Several cryptographic tools provide anonymity in a cryptographic sense, but solely using such a tool does not guarantee anonymity; for example, even if the underlying cryptographic primitives enable anonymity in some sense, a communication system using these tools may reveal the senders’ IP address. Moreover, since a certificate of public key infrastructure contains information of a key holder, and that contradicts anonymity of the key holder, the certificate must be removed. Therefore, it seems difficult to check the validity of the public key in an anonymous environment. That is, constructing a secure and anonymous communication protocol, where end-to-end encryption and anonymous authentication are achieved simultaneously, is an important issue to be solved.In ACM SAC 2014 (and IEEE Trans. Emerging Topics Comput. 2016), such a protocol was proposed, where it applies identity-based encryption (IBE) for packet encryption without contradicting anonymity. However, this protocol is inefficient and approximately 20 times slower than that of SSL communications because IBE requires heavy cryptographic pairing computations.In this paper, we propose a more efficient, secure, and anonymous communication protocol, which achieves the same security level as the IBE-based protocol does. The protocol is exempted from pairing computation for establishing a secure channel by applying hybrid encryption instead of IBE. We implement the protocol and show that it is more efficient (overall approximately 1.2 times faster) than the IBE-based protocol. In particular, the decryption algorithm of our protocol is several hundred times faster than that of the IBE-based protocol. In our protocol, we employ the ElGamal KEM scheme and 128-bit AES as the underlying KEM and DEM schemes, respectively, and we have used the TEPLA library for the prototype implementation.

Assessment of cold chain maintenance for routine immunization in Jamnagar district, Gujarat

Background: Immunization is one of the main components of primary healthcare. At the peripheral level, primary health center (PHC) is the key holder of cold chain system. One of the important elements for improving the immunization is cold chain and vaccine logistics management which is the backbone of immunization program. Objectives: The objectives of this study were to assess cold chain and logistics management for routine immunization at PHCs and community health centers (CHCs). Materials and Methods: It was a cross-sectional study conducted during November 2013–November 2014 at 20 PHCs and 10 CHCs of Jamnagar district using prestructured and pretested questionnaire. Result: A single person was assigned for cold chain handling at 15 out of 20 PHCs, all were trained and 9 out of 10 CHCs of whom only four were trained. At the time of visit, 56.7% cold chain equipments were locked. Only 36.7% cold chain equipments were having digital thermometers. Two PHCs and one CHC had stored other sera or vaccines in ice-lined refrigerators (ILRs). Proper placement of vaccine in ILR was seen at majority of PHCs and CHCs. Temperature records were proper, but alternate power source was available at 70% PHCs only. In only 20% PHCs, Medical Officers cross-checked temperature book at least 4 times in a month. Conclusion: Overall, cold chain management for routine immunization was good at all visited PHCs of Jamnagar, but some aspects need improvement such as internal monitoring, training for all cold chain handlers, and alternate source of energy in case of power failure.

Secure searchable encryption: a survey

Cloud computing facilitates convenient and on-demand network access to a centralized pool of resources. Currently, many users prefer to outsource data to the cloud in order to mitigate the burden of local storage. However, storing sensitive data on remote servers poses privacy challenges and is currently a source of concern. SE (Searchable Encryption) is a positive way to protect users sensitive data, while preserving search ability on the server side. SE allows the server to search encrypted data without leaking information in plaintext data. The two main branches of SE are SSE (Searchable Symmetric Encryption) and PEKS (Public key Encryption with Keyword Search). SSE allows only private key holders to produce ciphertexts and to create trapdoors for search, whereas PEKS enables a number of users who know the public key to produce ciphertexts but allows only the private key holder to create trapdoors. This article surveys the two main techniques of SE: SSE and PEKS. Different SE schemes are categorized and compared in terms of functionality, efficiency, and security. Moreover, we point out some valuable directions for future work on SE schemes.

Key-Aggregate Cryptosystem based on Elliptic Curve Cryptography for Data Sharing in Cloud Storage

It is important to share data securely, efficiently and flexibly in cloud storage. We describe public-key encryption technique based on elliptic-curve theory which is used to create faster, smaller and more efficient cryptographic keys. This publickey cryptosystem produces constant size cipher texts and user can aggregate any set of secret keys and make them as compact as single and can decrypt any set of cipher texts by using that compact aggregate key but, files outside the set remain confidential. In this cryptosystem it is possible to efficiently assign decryption rights for the set of cipher texts to any users. The secret key holder can release a constant-size aggregate key for set of cipher texts and this compact aggregate key conveniently shared with others with very limited secure storage. In this paper, we study how to create a decryption key more powerful so that it can allows decryption of multiple cipher texts, without increasing key size.

Security enhancement for dynamic key refreshment in neighborhood area network of smart grid

Wireless mesh networks are being considered as the most adequate topology for deployment in the neighborhood area network NAN domain in the smart-grid infrastructure, because its features such as self-organizing, scalability, and cost-efficiency complement to the NAN requirements. To provide security functionality to the NAN, the key refreshment strategy of the simultaneous authentication of equals or the efficient mesh security association protocol is an efficient way to make the network more resilient against various cyberattacks. However, it is discovered that when the key refreshment strategy is used, the efficient mesh security association protocol demonstrates a security vulnerability, leading to denial of service attacks. In this paper, a simple hash-based encryption scheme is proposed to prevent the unprotected messages from being replayed by the adversary with an enhancement to the key refreshment scheme to improve the resilience of the mesh key holder security handshake. The Protocol Composition Logic is used to describe the logical correctness of the proposed scheme, while the Process Analysis Toolkit is used to formally verify the security functionality against the malicious attacks. The efficiency analysis and the simulation results prove that the proposed scheme is reliable and efficient. Copyright © 2016 John Wiley & Sons, Ltd.

A Review on Key-Aggregate Cryptosystem for Climbable Knowledge Sharing in Cloud Storage

The Data sharing is an important functionality in cloud storage. In this article, we show how to securely, efficiently, and flexibly share data with others in cloud storage. We describe new public-key cryptosystems which produce constant-size ciphertexts such that efficient delegation of decryption rights for any set of ciphertexts are possible. The novelty is that one can aggregate any set of secret keys and make them as compact as a single key, but encompassing the power of all the keys being aggregated. In other words, the secret key holder can release a constant-size aggregate key for flexible choices of ciphertext set in cloud storage, but the other encrypted files outside the set remain confidential. This compact aggregate key can be conveniently sent to others or be stored in a smart card with very limited secure storage. We provide formal security analysis of our schemes in the standard model. We also describe other application of our schemes. In particular, our schemes give the first public-key patient controlled encryption for flexible hierarchy, which was yet to be known.

Dual trapdoor identity-based encryption with keyword search

Identity-based encryption with keyword search (IBEKS) is a useful cryptographic primitive for cloud computing, i.e., it allows a data owner to encrypt and store his data in a cloud storage server, and later the owner can use his/her private key to produce a search trapdoor for searching the encrypted data. Existing IBEKS schemes only focus on supporting efficient and complex queries for the private key holder, while the authority, who is in charge of the generation of the private keys for users, cannot efficiently search the encrypted data. However, some applications might require the authority to efficiently search the encrypted data intended for any user. To address this problem, in this paper, we introduce a new primitive named dual trapdoor identity-based encryption with keyword search (DTIBEKS). In this primitive, the authority can use a peculiar way to produce one more trapdoor, which allows the authority to search any identity's encrypted data. We formally give the definition and security model for DTIBEKS, and then propose a novel DTIBEKS scheme. We further prove the security of our proposed DTIBEKS without random oracles. It is worth noting that our scheme can be easily transformed into identity-based encryption with fuzzy keyword search.

Worldwide pharmacy revolution: Advocating for pharmacy at home and abroad

Worldwide pharmacy revolution: Advocating for pharmacy at home and abroad

Key Aggregate Policies for SecureData Sharing in Cloud Storage

Sensitive information modified should be firmly done to verify the integrity of cloud information, to stop it from being disclosed to or modified by unauthorized parties. Many enterprises supply information storage to the cloud mere a member of a company or information owner can merely share information with completely different members or users with confidentiality. The new public key aggregate policies that prove constant-size ciphertext wherever mere ciphertext unit labeled with sets of attributes and private keys unit associated with structures that management that user is able to decrypt. In several words, the key holder can unleash a constantsize aggregate key for versatile preferences of ciphertext set in cloud storage, but the other encrypted files outside the set keep secret to boot to authentication and privacy preservation this theme tries to satisfy all completely different security wants with key management and achieves higher quantifiability once the quantity of access levels can increase.

Certificate Based Encryption for SecuringBroker-Less Publish/Subscribe System inWireless Network

The security mechanisms such as authentication and confidentiality is highly challenging in a contentbased publish/subscribe system and due to the loose coupling of publishers and subscribers, authentication and confidentiality of publishers and subscribers is difficult to achieve. In particular content-based approaches in brokerless environments do not address confidentiality at all. This paper presents to provide confidentiality and authentication in a broker-less content-based publish-subscribe system. The authentication and confidentiality and other security approach of publishers and subscribers ensured, by adapting the certificate based encryption mechanism. In certificate based encryption signature not only acts as certificate but also as encrypt and decrypt key. To encrypt or to decrypt a message, a key holder needs both its public key and private key and an up-to-date certificate from an authorizer. Certificate-based encryption combines the best aspects of identity-based encryption and public key encryption. This mechanism describes how certificate-based encryption can be used to construct an efficient PKI requiring fewer infrastructures than any previous method.

Efekti albanskog terorizma na Kosovu i Metohiji

The very first ideas about secession of Kosovo and Metohija of the Republic of Serbia and the use of violence in achieving them appeared immediately after the First Balkan War (1912). The key pillars of this, secessionist motivated violence in Kosovo during and after the wars of liberation of Serbia (1912 and 1918). And between the two world wars, were kachach, during and after World War II that were ballistic groups of Albanian extremists. Violence based on their tradition, with unforeseeable serious consequences for vital interests of the Republic of Serbia, escalated in the last decade of the twentieth century, violence Albanian extremist group called the Kosovo Liberation Army (KLÁ), supported by influential members of the international community. In many papers, the analysis of the specific objectives, the holders-active entities, resources, facilities attack - passive subjects and consequences, as constituent elements of that violence, confirmed his terrorist character of the KLÁ as a terrorist profile of its key holder. In this regard, the work is the result of research in which the author, as a consequence of the analysis of the constituent elements of Albanian terrorism in Kosovo and Metohija, the end of the last century and the beginning of this century, identified scientifically described and classified the effects, or levels of achievement of objectives internal and holders Foreign support­ers. In addition to the indisputable proven effects in achieving the goals of the operational and intermediate levels, the work is proven and partial achievement of strategic-political (ethno-separatistic) internal target holders of Albanian terrorism in Kosovo and Metohija, defined as secession-the secession of Kosovo and Metohija from the Republic of Serbia. The deployment of international military, security and civilian forces in Kosovo and Metohija, with the tempo­rary transfer of jurisdiction of state authorities of the FRY and Serbia to the security and the UN mission (KFOR and UNMIK) and the EU (EULEX), work has been identified as an indisputable effect of engag­ing in foreign entities the resolution on the Kosovo issue. In addition, work has confirmed the assumption according to which the set-up and to achieve this strategic objective external entities was primarily based on their 'hidden' geopolitical interests, and not to publicly proclaimed goals defined as stopping a 'humanitarian catastrophe' in Kosovo and Metohija.

Key-Aggregate Cryptosystem for Scalable Data Sharing in Cloud Storage

Data sharing is an important functionality in cloud storage. In this paper, we show how to securely, efficiently, and flexibly share data with others in cloud storage. We describe new public-key cryptosystems that produce constant-size ciphertexts such that efficient delegation of decryption rights for any set of ciphertexts are possible. The novelty is that one can aggregate any set of secret keys and make them as compact as a single key, but encompassing the power of all the keys being aggregated. In other words, the secret key holder can release a constant-size aggregate key for flexible choices of ciphertext set in cloud storage, but the other encrypted files outside the set remain confidential. This compact aggregate key can be conveniently sent to others or be stored in a smart card with very limited secure storage. We provide formal security analysis of our schemes in the standard model. We also describe other application of our schemes. In particular, our schemes give the first public-key patient-controlled encryption for flexible hierarchy, which was yet to be known.

An Efficient Key-Policy Attribute-Based Encryption Scheme with Constant Ciphertext Length

There is an acceleration of adoption of cloud computing among enterprises. However, moving the infrastructure and sensitive data from trusted domain of the data owner to public cloud will pose severe security and privacy risks. Attribute-based encryption (ABE) is a new cryptographic primitive which provides a promising tool for addressing the problem of secure and fine-grained data sharing and decentralized access control. Key-policy attribute-based encryption (KP-ABE) is an important type of ABE, which enables senders to encrypt messages under a set of attributes and private keys are associated with access structures that specify which ciphertexts the key holder will be allowed to decrypt. In most existing KP-ABE scheme, the ciphertext size grows linearly with the number of attributes embedded in ciphertext. In this paper, we propose a new KP-ABE construction with constant ciphertext size. In our construction, the access policy can be expressed as any monotone access structure. Meanwhile, the ciphertext size is independent of the number of ciphertext attributes, and the number of bilinear pairing evaluations is reduced to a constant. We prove that our scheme is semantically secure in the selective-set model based on the general Diffie-Hellman exponent assumption.

A Fast Authentication Scheme for WiMAX–WLAN Vertical Handover

In view that authentication has made a significant determinant in handover delay, this paper presents a fast authentication mechanism for mobile stations roaming within a WiMAX---WLAN interconnected environment. Incorporating a key reuse design that prevents repeated transactions at a remote server, our mechanism distributes security contexts ahead of handover to a local trusted key holder which manages several sites. A target site, upon receiving a mobile station, retrieves the contexts locally for authentication purpose and thus completes handover efficiently. While employing a target prediction algorithm as an option, our mechanism distributes the contexts to target candidates as dictated, which further improves handover performance if target prediction hits and maintains its advantage even in a miss. In addition, the handover optimization design specified in WiMAX is extended to support WiFi-to-WiMAX handovers. We reason that the proposed mechanism does not compromise the system in any sense as well. Analytical and simulation results show that, despite key pre-distribution misses, our mechanism leads to marked improvement over counterpart schemes in terms of handover delay and packet loss, meeting delay-sensitive application requirements.