Multimedia cryptography — A review

Abstract

In Digital Communication and Multimedia application, security becomes an important role of transmission of data and images. The encryption is one of the ways to ensure security for multimedia data. The multimedia data comprises of text, image, audio and video. In recent years, the latest encryption technology has improved the security to multimedia data from unauthorized operations. Multimedia encryption techniques convert original data to another data that is hard to understand and is called cipher text. The process of encoding plain text messages into cipher text messages is called encryption and the reverse process of trans-forming cipher text back to plain text is called decryption. It has several applications like multimedia communication systems, medical imaging, Telemedicine and military communication. At present, there is several conventional data encryption algorithms are available. The major three conventional methods are widely used. They are AES, RSA, and IDEA are being used for encryption of text and binary data. The basic methods have fixed length of key. However, the conventional algorithms are inefficient to use them directly in multimedia data and color image encryption because of high correlation among pixels. Moreover, the multimedia data are often high redundancy of large volumes and require real-time analysis for better results. The bio-cryptography is one of the latest emerging research. The bio cryptography will address all the limitations of conventional cryptography. It will provide the enhanced security to data and images while transmitting or in storage. This will be efficiently used for improving the multimedia data encryption and decryption. The basic cryptography techniques are secret key, public key and hash functions. However, the cost and complexity is high in bio cryptography. There-fore, the bio cryptography will be used to specialized applications. The interface between biometric and cryptography depends on type of application and level of security. The selection of physical and behavioral characteristics will also depend on the required design and applications. Hence, this paper will focus on to review the latest developments to report the challenges and achievements including fundamental appraisal.