The concealment, the steganography success rate, and the steganographic capacity are key performance indicators to text steganography. The existing text steganography methods still have a low steganographic capacity, some syntactic or semantic ambiguity problems to some extent. We propose an electronic lattice construction method based on a padding game to hide a secret message. 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. To extract the message, the receiver fills the crossword according to the same game rules as the sender does, and calculates that unique hidden path based on the shared key. The experimental results and analyses show that its concealment is prominent, its steganography success rate is 100%, and it has a high steganographic capacity. It also has no readability issue as the steganography by generation usually does.

Introduction

With the rapid development of Internet technology, the dissemination of digital audio-visual products and other electronic publications become more and more convenient. Just as a coin has two sides, besides such facilitation, the new technologies also bring a lot of problems, such as information theft and disclosure, and other serious infringements. It has become a problem of great concern on how to make people not only enjoy the convenience but also effectively protect information security and digital rights. Information hiding technology [1] is one of potential approaches to these issues, one branch of which, i.e. steganography, is the practice of communicating a secret message by hiding it in a popular cover object. This approach can avoid the secret transmission to be noticed by an attacker and is attracting more and more attention. It plays an important role in protecting the information from uncovering, such as the secret communication. Based on the cover types, steganography can be divided into five categories: image steganography [2], [3], video steganography [4], [5], audio steganography [6]–[۸], text steganography [9] and network steganography [10]. As the most important and predominant media, a text is widely used in our daily life and work. This makes it difficult to arouse suspicion when a text is used as a cover, which conforms to the principal characteristics of a cover [11]. The text steganography was invented in ancient times. The most typical ones were the Tibetan head poems and the Tibetan tail poems [12].