Optimization Substitution Cipher and Hidden Plaintext in Image Data Using LSB Method

Abstract

Cryptography is a way to protect certain messages that have confidential properties or have properties that must be protected from unrelated parties. Substitution techniques have several algorithms such as hill cipher, vigenere cipher, one-time pad and others. This research is a development of previous research that has been carried out many combine substitution techniques. This research combines 4 substitution techniques that have been modified and stored messages that have been hidden into an image with the Least Significant Bit (LSB) algorithm. This research provides additional before the process of standard substitution techniques so that it will provide a more level of security even though the encryption process uses simple techniques and inserts messages into an image with PNG extension using LSB to improve security in messages. This is evidenced by the absence of color differences in the image so that it will not arouse suspicion. However, hex and the size of the image will change. besides this research found that images can only be implemented on social media such as Google+, Telegram, and Google Drive. Because social media like Facebook, WhatsApp, Instagram, and Pinterest will automatically convert, resizing to be smaller than the actual size.