Text steganographic method based on keyword replacement

The invention relates to a text steganographic method based on keyword replacement, in which important keywords can be replaced by the keywords desired by a sender through the replacement of two different forms of keywords so as to achieve the aim of freewill misleading. During the steganography, the keywords can be selected at will; keys are generated according to the relationship between the keywords before and after the replacement; and the original text can be extracted by a receiver according to a main key. The replaced keywords are determined by the sender, so that the replaced keywords have good pertinence and a better misleading effect and are difficult to show slips. In the opinion of a listener (opponent) that intercepts a disguised text, the sent disguised file is the original text as the text is meaningful, the file is generally meaningless after being encrypted, and the other steganographic methods such as steganography in video and audio files need multimedia files; and the receiver does not know that the original text undergoes steganography treatment and has a misleading function, and furthermore, the meaning of the disguised text is opposite to the meaning of the original text.