Persian/Arabic Unicode Text Steganography

Sending information secretly and communicating covertly have been of great interest for ages. On the other hand, text documents have been widely used and consequently various methods for hiding information in texts (text steganography) have been developed so far. In this paper a new method is proposed to hide information in digital Persian and Arabic Unicode texts.In Persian and Arabic, each letter can have four different shapes regarding to its position in the word. In this method by using this feature of Persian and Arabic languages and the way which documents are saved in the Unicode Standard, the information is hidden in Unicode text documents. This method has a good hiding capacity because it hides one bit in each word. Also this method does not make any apparent changes in the original text and have a perfect perceptual transparency.