Optik 168 (2018) 370–375 Contents lists available at ScienceDirect Optik journal homepage: www.elsevier.de/ijleo Original research article Cryptanalysis of multimedia encryption using elliptic curve cryptography Khoirom Motilal Singh ∗ , Laiphrakpam Dolendro Singh, Themrichon Tuithung Department of Computer Science and Engineering, National Institute of Technology, Nagaland 797103, India a r t i c l e i n f o Article history: Received 9 March 2018 Accepted 11 April 2018 Keywords: Multimedia encryption Elliptic curve cryptography Elliptic curve discrete logarithmic problem Cryptanalysis a b s t r a c t The encryption scheme proposed by Tawalbeh et al. [1] is based on elliptic curve cryptog- raphy (ECC). ECC depends on the difficulty to solve the elliptic curve discrete logarithmic problem. However we found that the order of Tawalbeh et al. elliptic curve is not large enough to protect from attacks like Baby Step, Giant Step attack or Pollard’s Rho attack. Sim- ulation of the encryption scheme using the elliptic curve parameters proposed by Tawalbeh et al. is carried out. Cryptanalysis has been successfully carried out to extract the private key from the public key and the encrypted image is deciphered revealing the plain image. © 2018 Elsevier GmbH. All rights reserved. 1. Introduction With the rapid growth in Internet and modern information communication technology, multimedia data are easily stored and shared between communication parties. Many researchers have come up with several cryptographic schemes in order to avoid unauthorized access to sensitive multimedia data. Classical encryption scheme such as Rivest–Shamir–Adleman (RSA), Data Encryption Standard (DES) are not effective for large and highly correlated data. Chaotic system, being the most commonly used techniques for encrypting data, many researchers have utilized its properties. The properties include sensitivity to initial conditions and ergodicity to define various encryption schemes. Despite of its benefits in applying to an encryption scheme, there are certain issues that need to address such as small key size and weak security. Many chaos-based encryption schemes [2–6] have already been cryptanalysed by various authors [7–11] respectively. ECC is a strong public key encryption scheme which can provide high security for a given key size compared to other encryption schemes whose difficulty depends on integer factorization or discrete logarithmic problem [12,13]. Detail explanation about ECC, mathematical proofs and applications are given in [14,15]. Various authors have used ECC base encryption scheme for securing multimedia data [16–19]. Hong et al. [20] cryptanalyse the encryption scheme proposed by Ahmed et al. [21] based on hybrid chaotic system and cyclic elliptic curve using known-plaintext attack. In this paper, cryptanalysis of the encryption scheme proposed by Tawalbeh et al. [1] is carried out, revealing the private key from the public key. Using the retrieved private key, the cipher image generated using Tawalbeh et al. encryption scheme is deciphered recovering the plain image transmitted by the sender. The rest of the paper is organized as: Tawalbeh et al. encryption scheme is explained in Section 2. Section 3 explains the concept of attacks applied on ECC (Naive attack, Baby Step, Giant Step attack and Pollard’s Rho attack). The simulation of the cryptanalysis performed on Tawalbeh et al. chosen elliptic curve is shown in Section 4. Conclusion is given in Section 5. ∗ Corresponding author. E-mail address: khmotilal@gmail.com (M.S. Khoirom). https://doi.org/10.1016/j.ijleo.2018.04.068 0030-4026/© 2018 Elsevier GmbH. All rights reserved.