An Efficient identity based Multi-receiver Signcryption Scheme using ECC

ABSTRACT Signcryption is a technique of performing signature and encryption in a single logical step. It is a secure and efficient technique of providing security between the sender and the receiver so that the data send by the sender should be made secure from various types of attacks such as desynchronization attacks, identity disclosure attack and spoofing attacks. Although there are many technique implemented for the generation of signature and encryption. Here a new and efficient technique of signcryption has been implemented in a multireceiver environment on the basis of identity of the receiver. The proposed work given here is the implementation of signcryption scheme using elliptic curve cryptography where the authentication between sender and the receiver is based on the identity of the receiver

A new encrypted data switching Protocol: Bridging IBE and ABE without loss of data confidentiality

Encryption technologies have become one of the most prevalent solutions to safeguard data confidentiality in may real-world applications, e.g., cloud-based data storage systems. Encryption outputting a relatively “static” format of encrypted data, however, may hinder further data operations, for example, encrypted data may need to be “transformed” into other formats for either computation or other purposes. In order to enable an encryption to be used in another device equipped with a different encryption mechanism, the concept of encryption switching is first proposed in CRYPTO 2016 for conversion particularly between Paillier and ElGamal encryptions. This paper considers the conversion between conventional identity-based and attribute-based encryptions and further proposes a concrete construction via the technique of proxy reencryption. The construction is proved to be CPA secure in the standard model under q-decisional parallel bilinear Diffie-Hellman exponent assumption. The performance comparisons highlight that our bridging mechanism reduces computation and communication cost on client side, especially when the data of client is encrypted and outsourced to remote cloud. The computational costs w.r.t. re-encryption (on server side) and decryption (on client side) are acceptable in practice

Achieving cybersecurity in blockchain-based systems: a survey

With The Increase In Connectivity, The Popularization Of Cloud Services, And The Rise Of The Internet Of Things (Iot), Decentralized Approaches For Trust Management Are Gaining Momentum. Since Blockchain Technologies Provide A Distributed Ledger, They Are Receiving Massive Attention From The Research Community In Different Application Fields. However, This Technology Does Not Provide With Cybersecurity By Itself. Thus, This Survey Aims To Provide With A Comprehensive Review Of Techniques And Elements That Have Been Proposed To Achieve Cybersecurity In Blockchain-Based Systems. The Analysis Is Intended To Target Area Researchers, Cybersecurity Specialists And Blockchain Developers. For This Purpose, We Analyze 272 Papers From 2013 To 2020 And 128 Industrial Applications. We Summarize The Lessons Learned And Identify Several Matters To Foster Further Research In This AreaThis work has been partially funded by MINECO, Spain grantsTIN2016-79095-C2-2-R (SMOG-DEV) and PID2019-111429RB-C21 (ODIO-COW); by CAM, Spain grants S2013/ICE-3095 (CIBERDINE),P2018/TCS-4566 (CYNAMON), co-funded by European Structural Funds (ESF and FEDER); by UC3M-CAM grant CAVTIONS-CM-UC3M; by the Excellence Program for University Researchers, Spain; and by Consejo Superior de Investigaciones Científicas (CSIC), Spain under the project LINKA20216 (“Advancing in cybersecurity technologies”, i-LINK+ program)

Enhanced Outsider-anonymous Broadcast Encryption with Subset Difference Revocation

This paper puts forward an efficient broadcast encryption in public key setting employing ternary tree subset difference method for revocation. It provides outsider anonymity disabling the revoked users from getting any information of message and concealing the set of subscribed users from the revoked users. Our approach utilizes composite order bilinear group setting and exhibits significant improvement in the broadcast efficiency. The proposed scheme compares favourably over the existing similar schemes in standard model. The public key and secret key sizes are poly-logarithmic while the ciphertext size is sub linear in total number of users. Our scheme achieves selective security against chosen plaintext attack in the standard model under reasonable assumptions

Fault-Tolerant Aggregate Signatures

Aggregate signature schemes allow for the creation of a short aggregate of multiple signatures. This feature leads to significant reductions of bandwidth and storage space in sensor networks, secure routing protocols, certificate chains, software authentication, and secure logging mechanisms. Unfortunately, in all prior schemes, adding a single invalid signature to a valid aggregate renders the whole aggregate invalid. Verifying such an invalid aggregate provides no information on the validity of any individual signature. Hence, adding a single faulty signature destroys the proof of integrity and authenticity for a possibly large amount of data. This is largely impractical in a range of scenarios, e.g. secure logging, where a single tampered log entry would render the aggregate signature of all log entries invalid. In this paper, we introduce the notion of fault-tolerant aggregate signature schemes. In such a scheme, the verification algorithm is able to determine the subset of all messages belonging to an aggregate that were signed correctly, provided that the number of aggregated faulty signatures does not exceed a certain bound. We give a generic construction of fault-tolerant aggregate signatures from ordinary aggregate signatures based on cover-free families. A signature in our scheme is a small vector of aggregated signatures of the underlying scheme. Our scheme is bounded, i.e. the number of signatures that can be aggregated into one signature must be fixed in advance. However the length of an aggregate signature is logarithmic in this number. We also present an unbounded construction, where the size of the aggregate signature grows linearly in the number of aggregated messages, but the factor in this linear function can be made arbitrarily small. The additional information encoded in our signatures can also be used to speed up verification (compared to ordinary aggregate signatures) in cases where one is only interested in verifying the validity of a single message in an aggregate, a feature beyond fault-tolerance that might be of independent interest. For concreteness, we give an instantiation using a suitable cover-free family

Information-Theoretic Timed-Release Security: Key-Agreement, Encryption, and Authentication Codes

In this paper, we study timed-release cryptography with information-theoretic security. As fundamental cryptographic primitives with information-theoretic security, we can consider key-agreement, encryption, and authentication codes. Therefore, in this paper we deal with information-theoretic timed-release security for all those primitives. Specifically, we propose models and formalizations of security for information-theoretic timed-release key-agreement, encryption, and authentication codes; we also derive tight lower bounds on entities\u27 memory-sizes required for all those ones; and we show optimal constructions of all those ones. Furthermore, we investigate a relationship of mechanisms between information-theoretic timed-release key-agreement and information-theoretic key-insulated key-agreement. It turns out that there exists a simple algorithm which converts the former into the latter, and vice versa. In the sense, we conclude that these two mechanisms are essentially close