A Novel Coverless Text Steganographic Algorithm Based on Polynomial Encryption

Aiming at the problems of low text utilization rate and ambiguity of secret information extraction in the "tag + keyword" coverless information hiding methods, we propose a coverless information hiding method of Chinese text based on polynomial encryption in this paper. The secret data communication is realized by the analogously forged URLs transmission, which improves the security of mobile computing to avoid the risk that the carrier texts are attacked maliciously. The text utilization rate and retrieval success rate are improved by using tags to select multiple keywords to expand the number of keywords in the index table. The keyword's location in secret message is obtained through text vocabulary matching, and the tag index and location information are encrypted by polynomial for secret information transmission. The split keywords of secret message can be transmitted in disorder. The experimental result shows that the secret message can be successfully extracted by sorting the extracted keywords according to the frequency and relevance of their combined tags. In our experiments with different test databases, both the hiding success rate and the average hiding capacity are improved with higher test values than other existing methods.