A New Text Steganography Method by Using Non-Printing Unicode Characters and Unicode System Characteristics in English/Arabic documents

The massive explosion in computer technology and communication has encouraged the development of steganography and water marking, where breathed the spirit of steganography and made it the top security technique to protect and preserve the rights and privacy. So steganography is the one of important types of hide information techniques that has evolved a lot in the past years. In this paper, we introduce a new approach for text steganography in text documents (word Excel). In this method, two techniques are marged. First method, use the special Unicode standard characters, zero width non joiner (ZWNJ) and zero width joiner (ZWJ) characters (which have the non-printing properties) to embedding the bits of secret message into English letters, Arabic related letter, Arabic letters separated if they connect, and English/Arabic numbers. Second method; use Unicode system characteristics to embedding the bits of secret message into separate Arabic letters. This method has high capacity, it can hide one bit in each letter or number in the cover_file, and it satisfies perceptual transparency,by dose not make any apparent changes in the original text. In our methoud we increase the level of security by encode the secret message before embedding it into the cover_text by using Advanced Encryption Standard Algorithm (AES-128).