Blockchain as a CA: A Provably Secure Signcryption Scheme Leveraging Blockchains

Tzung-Her Chen,Fuh-Gwo Jeng,Ting-Le Zhu,Chien-Lung Wang,Kaitai Liang

doi:10.1155/2021/6637402

Tzung-Her Chen, Fuh-Gwo Jeng + Show 3 more

Open Access

https://doi.org/10.1155/2021/6637402

Copy DOI

Abstract

Although encryption and signatures have been two fundamental technologies for cryptosystems, they still receive considerable attention in academia due to the focus on reducing computational costs and communication overhead. In the past decade, applying certificateless signcryption schemes to solve the higher cost of maintaining the certificate chain issued by a certificate authority (CA) has been studied. With the recent increase in the interest in blockchains, signcryption is being revisited as a new possibility. The concepts of a blockchain as a CA and a transaction as a certificate proposed in this paper aim to use a blockchain without CAs or a trusted third party (TTP). The proposed provably secure signcryption scheme implements a designated recipient beforehand such that a sender can cryptographically facilitate the interoperation on the blockchain information with the designated recipient. Thus, the proposed scheme benefits from the following advantages: (1) it removes the high maintenance cost from involving CAs or a TTP, (2) it seamlessly integrates with blockchains, and (3) it provides confidential transactions. This paper also presents the theoretical security analysis and assesses the performance via the simulation results. Upon evaluating the operational cost in real currency based on Ethereum, the experimental results demonstrate that the proposed scheme only requires a small cost as a fee.

Highlights

IntroductionIn 1997, Zheng presented the first signcryption concept that simultaneously fulfilled the functions of both the digital signature and public key encryption in a logical single step and achieved significantly lower costs than those required by “signature followed by encryption” [1]
With the rapid development of information and network applications, confidentiality, integrity, and nonrepudiation are the main security concerns. us, encryption and digital signatures have become two main fundamental technologies for any well-defined cryptosystem.In 1997, Zheng presented the first signcryption concept that simultaneously fulfilled the functions of both the digital signature and public key encryption in a logical single step and achieved significantly lower costs than those required by “signature followed by encryption” [1]
In 1984, Shamir presented a novel identity-based cryptosystem (IBC) [18] in which a random string was set as the participant’s public key, and the corresponding private key was generated by a trusted third party (TTP) called the key generation center (KGC). is design eliminated the high cost of maintaining a traditional certificatebased PKI

Summary

Introduction

In 1997, Zheng presented the first signcryption concept that simultaneously fulfilled the functions of both the digital signature and public key encryption in a logical single step and achieved significantly lower costs than those required by “signature followed by encryption” [1]. There have been increasingly more signcryption schemes formed using either traditional public key infrastructure- (PKI-) based [1, 2], identity-based [3,4,5,6,7], or certificateless-based [8,9,10,11,12,13,14,15,16,17] digital signatures. The identity-based signcryption schemes in Ref. [4, 5], to name a few, suffer the key escrow problem

Objectives

Results

Discussion

Conclusion