تشخیص هویت و رمزگذاری تصویر دیجیتال با استفاده از امضای دیجیتالی Digital Image Authentication and Encryption using Digital Signature

I. INTRODUCTION In modern era, technology has its own benefits and pitfalls. The major drawbacks include the unethical intrusion over the channels to steal the important information from the sender. To reduce the information leakage over the channels, various encryption methods [13, 14] have been proposed. With the advancement in technology, the security of digital images has become more and more crucial since the communications of digital products over internet are taking place more and more frequently. The organizations are migrating towards the electronic documents to reduce the paper work. To safeguard the electronic documents from potential hackers, public-key cryptography [1, 3, 6] known as digital signatures are used to authenticate the data sent over the channels. The image encryption and decryption algorithm is designed and implemented to provide confidentiality and protection in transmission of information in digital form [9]. Encryption can protect the privacy of data, but other methods are still needed to protect the integrity and authenticity of data. For example verification of a message authentication codes (MAC) or a digital signature. A digital signature [7] has many advantages like relative alleviate of laying down that the signature is authentic, the difficulty of forging a signature, the nontransferability of signature, the difficulty of altering signature, and the nonrepudiation of digital signature to insure that the signer cannot later deny signing. The signature must employ some information which is unique to sender to preclude both counterfeit and denial [8]. It must be comparatively easy to produce. To tackle this problem, a simple and effective method employing the concept of digital signature and error coding technique for image encryption is proposed by Aloka [1]. In Aloka et al. the digital signature is appended to the encoded image which is obtained by applying BCH encoding technique. At the receiver side, the digital signature can be employed to verify the legitimacy of the image. A digital correlation technique is used to verify the legitimacy of the deciphered image. In this paper, we tapped the features of SHA-1 hash scheme, Reed Solomon algorithm and digital signature to verify the authenticity of the image received. We used chaotic logistic map to spread the digital signature within the encrypted image, consequently making the proposed technique secure.