Research And Design Of Text-based Steganography Without Carrier

When the network technology and multimedia technology make the communication convenient and fast,the security problem is one's main concern.The information hiding technology can protect the content security of information.Its main principal idea is to hide the communication existence by embedding a secret message into a carrier.The text is the most popular media,but its redundancy is less,so the hiding capacity is usually low when steganography by modification is used.Further,the steganography by modification will cause the loss of secret messages by reformatting/retyping and the text fluency might also become bad.That is,their robustness and concealment are poor.To solve the above problems,two different algorithms are proposed as follows.(1)An electronic lattice construction method is proposed based on a padding game.This method first computes the length of a secret message and a key is worked out based on the length;the walking rule,the constraints to a hidden path,the initial size of a grid and the starting cell are determined based on the key and a unique hidden path can be figured out for the given secret;then the secret message is stored in the cells along the unique path and all the remaining cells in the grid are filled according to the padding game rules,which helps to obscure that secret message;finally,elements in some cells are removed to get the crossword that will be shared with the receiver.(2)A coverless text information hiding algorithm is proposed based on parts of speech.Steganography can be implemented in two ways,i.e.,the steganography by search and synthesis.Firstly,a data set is analyzed statistically according to part of speech.The words can be converted into binary strings based on the word frequency so the parts of speech corpus and text corpus are established.The compositions of sentences are also analyzed to construct sentence templates.The corresponding steganography by search will match the secret message with a text in the text corpus by comparing their corresponding binary string.The steganography by synthesis will choose unambiguous words in that context from the part-of-speech corpus according to the binary of secret messages,and fill them into sentence templates to generate a stego-text.The above-mentioned methods will not modify the existing carrier,so it can resist the attacks,such as reformatting or retyping.That is,their robustness and concealment are better.Their steganography success rate is 100%.Besides,it can be employed in other languages and has good extensibility.