Software implementation of steganographic hiding of text information in a graphic file using the LSB method

Abstract

The paper presents the code of a training program for steganographic hiding of text information in graphic files. Hiding is implemented using the “least significant bit” (LSB) method in Python. The program can be used for both educational and practical purposes. The Pillow library was used to implement the program. This graphic library is not specialized for steganographic needs. A positive quality of the library is the ability to visualize the information hiding mechanism. This is interesting for educational purposes. Working within the Pillow library allows us to see the mechanism of information hiding at the bit level of individual graphics pixels at the level of a fairly concise program code. The program was tested with texts of different lengths and with graphic containers (photographs) of different types. The experiment showed the correct introduction of texts into a graphic file and the corresponding extraction of texts from these files. The study of empty and corresponding filled containers (photographs) did not reveal any differences and suspicions of text bookmarks. Analysis of photographs and manipulations with them at the level of individual bits also has educational value in the sense of revealing the method of fixing the corresponding physical signal. The latter gives an idea of the methods of encoding static images, the noise level, the magnitude of the useful physical signal and the sensitivity limits of human vision. The presented program code can be used both in cryptography classes and in practical programming