The proposed scheme’s security is proven under the elliptic curve discrete logarithm assumption in the random oracle model. Results of comparing our scheme with existing pairing-free certificate-based signature schemes, shows that ours has much lower computational cost. | International Journal of Computer Networks and Communications Security VOL. 3, NO. 2, FEBRUARY 2015, 33–42 Available online at: E-ISSN 2308-9830 (Online) / ISSN 2410-0595 (Print) Utilization of ECDLP for Constructing a New Certificate Based Digital Signature Leili Abedi-Ostad1 and Morteza Nikooghadam2 1, 2 Department of Computer Engineering, University of Imam Reza, Mashhad 91735-553, Iran E-mail: 1leilaabediostad@, ABSTRACT Digital signatures that are used to achieve the integrity along with the authentication could be classified into various types. PKI based, ID based, certificate based and certificateless digital signatures are the most important types. Regarding advantages of certificate-based signatures (CBS), we want to propose a CBS scheme by means of employing elliptic curve discrete logarithm problem (ECDLP).The proposed scheme’s security is proven under the elliptic curve discrete logarithm assumption in the random oracle model. Results of comparing our scheme with existing pairing-free certificate-based signature schemes, shows that ours has much lower computational cost. Keywords: Elliptic Curve Discrete Logarithm Problem, Certificate-Based Digital Signature, Random Oracle Model, Pairing-Free, Elliptic Curve Cryptography. 1 INTRODUCTION In traditional public key cryptography (PKC), the public key of user should be certified by certification authority (CA). This approach has difficulties for managing certificates. For solving this problem, Shamir [1] presented identity based cryptography (IBC), which means user’s public key is made of his/her unique identity. In this scheme, private key of user is created by a private key generator (PKG). Since PKG has private key of all users, he/she can impersonate them. This problem is called key escrow [2]. There are two schemes for solving this problem. One of them is certificateless public key cryptography (CL-PKC). This scheme was presented by .
