Technology has improved significantly, and usage of smart systems has increased the risk to secure data and privacy. Since most operating systems come with built-in apps that aren't secure, there is rapid increase in risk of information or data cloning, forgery, tampering, counterfeiting, etc. End users will suffer an unrecoverable loss as a result, particularly with regard to social media personal data and banking applications. An efficient and robust technique which has Hill cipher combination with elliptic curve cryptography is proposed to deal with major threats and improve data security. This technique uses LSB (Least Significant Bit) watermarking to embed DCT coefficients of an image and ciphertext of message into base image. Using Hill Cipher algorithm, the ciphertext is produced. Elliptic Curve cryptography (ECC) and combination with Hill cipher to increase complexity, considering the fact that it has poor data security and is readily cracked. The key is generated by using ECC algorithm, and this key is used with the Hill cipher technique to produce ciphertext. Cryptography and Steganography both combined provide the data with greater legitimacy and ownership for media applications. Without a proper key, it proves difficult to get the hidden message and the image. For multimedia applications, the performance of hiding data and image in image data has been analyzed.

Keywords : Steganography, Cryptography, Elliptic Curve Cryptography, Hill Cipher, Self-Invertible Matrix, Discrete Cosine Transform, Least Significant Bit.