A covert communication method via spreadsheets by secret sharing with a self-authentication capability

摘要

A new covert communication method with a self-authentication capability for secret data hiding in spreadsheets using the information sharing technique is proposed. At the sender site, a secret message is transformed into shares by Shamir's (k, n)-threshold secret sharing scheme with n = k + l, and the generated k +1 shares are embedded into the number items in a spreadsheet as if they are part of the spreadsheet content. And at the receiver site, every k shares among the k +1 ones then are extracted from the stego-spreadsheet to recover k +1 copies of the secret, and the consistency of the k +1 copies in value is checked to determine whether the embedded shares are intact or not, achieving a new type of blind self-authentication of the embedded secret. By dividing the secret message into segments and applying to each segment the secret sharing scheme, the integrity and fidelity of the hidden secret message can be verified, achieving a covert communication process with the double functions of information hiding and self-authentication. Experimental results and discussions on data embedding capacity, authentication precision, and steganalysis issues are also included to show the feasibility of the proposed method.