IMPLEMENTATION OF LEMPEL-ZIV-WELCH ALGORITHM FOR SECRET INFORMATION COMPRESSION ON EMAIL HEADER STEGANOGRAPHY

• Main Author: Caesar - NIM : 13514041 , Varian
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/31447
• Institution: Institut Teknologi Bandung

<p align="justify">Noiseless Steganography (Nostega) is a steganographic technique that does not change the authenticity of the message concealing medium. Unlike the ordinary steganography that hides secret messages on a media, Nostega camouflage the secret message into an authentic cover itself. Email Header Steganography or better known as HeadStega is one of the methods in NoStega that makes the email header part as a means of concealing the message. In HeadStega, the secret message is converted into an email header cover, the most commonly used is the destination email address. There is a weakness in HeadStega by using a header in the form of a destination email address, namely the storage capacity of messages that are still low, especially for large size of secret messages. <br /> <br /> <br /> This final project tries to increase HeadStega's concealment capacity by modifying messagehiding process and utilizing data compression techniques to compress the file size. The compression algorithm used is the Lempel-Ziv-Welch (LZW) algorithm. LZW is chosen because it is flexible, compression and decompression process between communicating parties can run using the same string table. In contrast to Huffman which uses different Huffman trees for different messages. Test results show that the use of LZW and modification of hiding techniques can improve email generation efficiency on average by 48.85% for text file types and averaging 49.67% for binary file types. <p align="justify"> <br /> <br />