Identity Based Online/Offline Signcryption Scheme

Online/Offline signcryption is a cryptographic primitive where the signcryption process is divided into two phases - online and offline phase. Most of the computations are carried out offline (where the message and the receiver identity are unavailable). The online phase does not require any heavy computations like pairing, multiplication on elliptic curves and is very efficient. To the best of our knowledge there exists three online/offline signcryption schemes in the literature : we propose various attacks on all the existing schemes. Then, we give the first efficient and provably secure identity based online/offline signcryption scheme. We formally prove the security of the new scheme in the random oracle model \cite{BellareR93}. The main advantage of the new scheme is, it does not require the knowledge of message or receiver during the offline phase. This property is very useful since it is not required to pre-compute offline signcryption for different receivers based on the anticipated receivers during the offline phase. Hence, any value generated during the offline phase can be used during the online phase to signcrypt the message to a receiver during the online phase. This helps in reducing the number of values stored during the offline phase. To the best of our knowledge, the scheme in this paper is the first provably secure scheme with this property

Online/Offline Identity-Based Signcryption Revisited

In this paper, we redefine a cryptographic notion called Online/Offline Identity-Based Signcryption. It is an ``online/offline\u27\u27 version of identity-based signcryption, where most of the computations are carried out offline while the online part does not require any heavy computations such as pairings or multiplications on elliptic curve. It is particularly suitable for power-constrained devices such as smart cards. We give a concrete implementation of online/offline identity-based signcryption, which is very efficient and flexible. Unlike all the previous schemes in the literature, our scheme does not require the knowledge of receiver\u27s information (either public key or identity) in the offline stage. The receiver\u27s identity and the message to be signcrypted are only needed in the online stage. This feature provides a great flexibility to our scheme and makes it practical to use in real-world applications. To our knowledge, our scheme is the first one in the literature to provide this kind of feature. We prove that the proposed scheme meets strong security requirements in the random oracle model, assuming the Strong Diffie-Hellman (SDH) and Bilinear Diffie-Hellman Inversion (BDHI) are computationally hard

An Efficient Online/Offline Signcryption Scheme for Internet of Things in Smart Home

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An Elliptic Curve-based Signcryption Scheme with Forward Secrecy

An elliptic curve-based signcryption scheme is introduced in this paper that effectively combines the functionalities of digital signature and encryption, and decreases the computational costs and communication overheads in comparison with the traditional signature-then-encryption schemes. It simultaneously provides the attributes of message confidentiality, authentication, integrity, unforgeability, non-repudiation, public verifiability, and forward secrecy of message confidentiality. Since it is based on elliptic curves and can use any fast and secure symmetric algorithm for encrypting messages, it has great advantages to be used for security establishments in store-and-forward applications and when dealing with resource-constrained devices.Comment: 13 Pages, 5 Figures, 2 Table

Improved identity-based online/offline encryption

The notion of online/offline encryption was put forth by Guo, Mu and Chen (FC 2008), where they proposed an identity-based scheme called identity-based online/offline encryption (IBOOE). An online/ offline encryption separates an encryption into two stages: offline and online. The offline phase carries much more computational load than the online phase, where the offline phase does not require the information of the message to be encrypted and the identity of the receiver. Subsequently, many applications of IBOOE have been proposed in the literature. As an example, Hobenberger and Waters (PKC 2014) have recently applied it to attribute-based encryption. In this paper, we move one step further and explore a much more efficient variant.We propose an efficient semi-generic transformation to obtain an online/offline encryption from a tradition identity-based encryption (IBE). Our transformation provides a new method to separate the computation of receiver’s identity into offline and online phases. The IBOOE schemes using our transformation saves one group element in both offline and online phases compared to other IBOOE schemes in identity computing. The transformed scheme still maintains the same level of security as in the original IBE scheme

A Survey on Two New Secure and Efficient Data Transmission Protocols SET-IBS and SET-IBOOS for WSN

Data transmission in a secure way is a critical issue for wireless sensor networks (WSNs). Clustering is an effective and practical way to enhance the system performance of WSNs. The system proposes two new Secure and Efficient Data Transmission Protocols. This technique is useful for Cluster Based Wireless Sensor Networks. SET-IBS and SET-IBOOS are proposed protocols which uses Identity Based Digital Signature (IBS) and Identity Based Online/Offline Digital Signatures respectively. In general, for any secure data transmission protocols key exchange is a big overhead. This is removed in the proposed system by introducing Base Station. SET-IBOOS Scheme reduces the computational overhead. DOI: 10.17762/ijritcc2321-8169.15036