رمزنگاری چندرسانه ای سری با استفاده از رمزنگاری منحنی بیضی شکل Cryptanalysis of multimedia encryption using elliptic curve cryptography

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 ofthe 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.