Identity-Based Secure Distributed Data Storage Schemes

cegon technologies, 2019

This paper presents a novel Multi-message Ciphertext Policy Attribute-Based Encryption (MCP-ABE) technique, and employs the MCP-ABE to design an access control scheme for sharing scalable media based on data consumers' attributes (e.g., age, nationality, or gender)rather than an explicit list of the consumers' names. The scheme is efficient and flexible because MCP-ABE allows a content provider to specify an access policy and encrypt multiple messages within one Ciphertext such that only the users whose attributes satisfy the access policy can decrypt the Ciphertext. Moreover, the paper shows how to support resource-limited mobile devices by offloading computational intensive operations to cloud servers while without compromising data privacy EXISTING SYSTEM: A promising approach to access control in content sharing services is to empower users to enforce access controls on their data directly, rather than through a central administrator. However, this requires flexible and scalable cryptographic key management to support complex access control policies. A native access control solution is to assign one key for each user attribute, distribute the appropriate keys to users who have the corresponding attributes, and encrypt the media with the attribute keys repeatedly Another method is to classify users into different roles based on their attributes, assign role keys to users, and then encrypt the content using the role keys. However, this approach results in high complexity, i.e., the number of keys for each user and the number of cipher texts for one message are on the order of where is the

Attribute-based signature (ABS) enables users to sign messages over attributes without revealing any information other than the fact that they have attested to the messages. However, heavy computational cost is required during signing in existing work of ABS, which grows linearly with the size of the predicate formula. As a result, this presents a significant challenge for resource-constrained devices (such as mobile devices or RFID tags) to perform such heavy computations independently. Aiming at tackling the challenge above, we first propose and formalize a new paradigm called Outsourced ABS, i.e., OABS, in which the computational overhead at user side is greatly reduced through outsourcing intensive computations to an untrusted signing-cloud service provider (S-CSP). Furthermore, we apply this novel paradigm to existing ABS schemes to reduce the complexity. As a result, we present two concrete OABS schemes: i) in the first OABS scheme, the number of exponentiations involving in signing is reduced from O(d) to O(1) (nearly three), where d is the upper bound of threshold value defined in the predicate; ii) our second scheme is built on Herranz et al.'s construction with constant-size signatures. The number of exponentiations in signing is reduced from O(d2 ) to O(d) and the communication overhead is O(1). Security analysis demonstrates that both OABS schemes are secure in terms of the unforgeability and attribute-signer privacy definitions specified in the proposed security model. Finally, to allow for high efficiency and flexibility, we discuss extensions of OABS and show how to achieve accountability as well.

cegon technologies, 2019

Content-based image retrieval (CBIR) applications have been rapidly developed along with the

cegon technologies, 2019

Intentional or unintentional leakage of confidential data is undoubtedly one of the most severe security threats that organizations face in the digital era. The threat now extends to our personal lives: a plethora of personal information is available to social networks and smartphone providers and is indirectly transferred to untrustworthy third party and fourth party applications.

cegon technologies, 2019

The capability of selectively sharing encrypted data with different users via public cloud storage may greatly ease security concerns over inadvertent data leaks in the cloud. A key challenge to designing such encryption schemes lies in the efficient management of encryption keys. The desired flexibility of sharing any group of selected documents with any group of users demands different encryption keys to be used for different documents. However, this also implies the necessity of securely distributing to users a large number of keys for both encryption and search, and those users will have to securely store the received keys, and submit an equally large number of keyword trapdoors to the cloud in order to perform search over the shared data. The implied need for secure communication, storage, and complexity clearly renders the approach impractical. In this paper, we address this practical problem, which is largely neglected in the literature, by proposing the novel concept of key aggregate searchable encryption (KASE) and

cegon technologies, 2019

Cloud storage system provides facilitative file storage and sharing services for distributed clients.

International Journal of Computer Science and Mobile Computing (IJCSMC), 2023

Digital signals are used in many vital applications, and since the volume of this data is very large, it is necessary to represent this data with a set of values and in a small size in order to increase the speed of processing the digital signal, because the applications that use this data need a high execution speed. In this paper research a detailed study of kmeans clustering and wavelet packet tree decomposition will be introduced, Using these methods to process any type of digital signals will lead to represent the digital data by a set of small number of values, this set will be used as a fingerprint to identify the digital data. Kmeans clustering method and wavelet tree decomposition will be used to create a fingerprints for speech signals, color images and gray images, the obtained results will be analyzed to give the user a bets way to create a fingerprint for any type of digital data, which is required to build any computer system, which use the digital data as an input.

UNSL, 2017

Älgebra y GeometriÄ analitica para estudiÄntes de universidÄd

Ελληνική Επιθεώρηση Πολιτικής Επιστήμης

To άρθρο αυτό επικεντρώνεται στις επιπτώσεις της επικοινωνιακής δυναμικής στο κομματικό πεδίο υπό το φως δύο διαδικασιών που προσδιορίζουν τη σχέση ΜΜΕ και πολιτικών κομμάτων. Η πρώτη διαδικασία είναι εξωστρεφής: πρόκειται για την αξιοποίηση από τα ελληνικά κοινοβουλευτικά πολιτικά κόμματα των επικοινωνιακών δεξιοτήτων επαγγελματιών που βρίσκονται εκτός κομματικών δομών, όπως άλλωστε αφήνει να διαφανεί η συζήτηση περί «μεσοποίησης» και «επαγγελματοποίησης» της πολιτικής. Η αποδυνάμωση, μεταξύ άλλων, της κομματικής βάσης και η αυτονόμηση των διευθυντικών ομάδων στην Ελλάδα, οδήγησε στην ανάδειξη των πολιτικών εμπειρογνωμόνων οι οποίοι υποκαθιστώντας, κυρίως σε προεκλογικές συνθήκες, ορισμένες βασικές οργανωτικές και εκτελεστικές λειτουργίες των πολιτικών κομμάτων επέφεραν ανακατατάξεις στο εσωτερικό τους. Η δεύτερη διαδικασία είναι εσωστρεφής: πρόκειται για την αξιοποίηση από τα πολιτικά κόμματα επικοινωνιακών πόρων εντός κομματικών δομών. Πιο ειδικά, εστιάζουμε στην ανάδυση άτυπων ηγετικών επικοινωνιακών ομάδων με αυξημένες δραστηριότητες ως προς τη χάραξη της καθημερινής πολιτικής στρατηγικής των κομμάτων, στη μερική ανανέωση του πολιτικού προσωπικού των κομμάτων και την επιλογή σε ορισμένες καίριες πολιτικές θέσεις προσώπων που αντλούν το κεφάλαιό τους από την επικοινωνιακή τεχνογνωσία και, τέλος, στις μεταμορφώσεις της προγραμματικής πολιτικής. Διερωτόμαστε, τελικά, τι συνεπάγονται οι παραπάνω διαδικασίες για την ίδια την αυτονομία του κομματικού πεδίου.