Two Efficient outsourced ABS (OABS) Schemes Denoted By OABS-I And OABS-II To Build An Efficient outsourced Verifying Protocol

Attribute-based signature (ABS) facilitates revelry to mark a message with fine-grained access control over make out information. Particularly, in an ABS system, users get hold of their attribute private keys from an attribute authority, with which they can presently sign messages for any predicate fulfilled by their attributes. We first advise and formalize a new concept called Outsourced ABS, i.e., OABS, in which the computational overhead at user side is really concentrated through outsourcing concentrated computations to an untrusted signing-cloud service provider (S-CSP). In addition, we be relevant this novel paradigm to existing ABS schemes to decrease the difficulty

Server-Supported Decryption for Mobile Devices

We propose a threshold encryption scheme with two-party decryption, where one of the keyshares may be stored and used in a device that is able to provide only weak security for it. We state the security properties the scheme needs to have to support such use-cases, and construct a scheme with these properties

A Blockchain-Assisted Hash-Based Signature Scheme

We present a server-supported, hash-based digital signature scheme. To achieve greater efficiency than current state of the art, we relax the security model somewhat. We postulate a set of design requirements, discuss some approaches and their practicality, and finally reach a forward-secure scheme with only modest trust assumptions, achieved by employing the concepts of authenticated data structures and blockchains. The concepts of blockchain authenticated data structures and the presented blockchain design could have independent value and are worth further research

A New Approach to Constructing Digital Signature Schemes (Extended Paper)

A new hash-based, server-supported digital signature scheme was proposed recently. We decompose the concept into forward-resistant tags and a generic cryptographic time-stamping service. Based on the decomposition, we propose more tag constructions which allow efficient digital signature schemes with interesting properties to be built. In particular, the new schemes are more suitable for use in personal signing devices, such as smart cards, which are used infrequently. We define the forward-resistant tags formally and prove that (1) the discussed constructs are indeed tags and (2) combining such tags with time-stamping services gives us signature schemes

CHARIOT: Cloud-Assisted Access Control for the Internet of Things

The Internet of Things (IoT) technology has expanded widely across the world, promising new data management opportunities for industries, companies and individuals in different sectors, such as health services or transport logistics. This trend relies on connecting devices/things to collect, exchange and store data. The exponentially increasing number of IoT devices, their origin diversity, their limited capabilities in terms of resources, as well as the ever-increasing amount of data, raise new challenges for security and privacy protection, precluding traditional access control solutions to be integrated to this new environment. In this paper, we propose a reliable server-aided policy-based access control mechanism, named CHARIOT, that enables an IoT platform to verify credentials of different devices requesting access (read/write) to the data stored within it. CHARIOT permits IoT devices to authenticate themselves to the platform without compromising their privacy by using attribute-based signatures. Our solution also allows secure delegation of costly computational operations to a cloud server, hence relieving the workload at IoT devices\u27 side

Server assisted signatures revisited

One of the main objectives of server-assisted computation is to reduce the cost of generating public key signatures for ordinary users with their constrained devices. On the other hand, based on nothing more than a one-way function, one-time signatures provide an attractive alternative to public key signatures. This paper revisits server assisted computation for digital signatures to show server assisted one-time signature (SAOTS) that combines the benefits of these two efficiency solutions. The proposed protocol turns out to be a more computational and round-efficient protocol than previous verifiable-server approaches. In addition, SAOTS offers other advantages like verification transparency, getting rid of public key operations for the ordinary user and proving the server's cheating without storing the signatures