Steganography using the Fourier Transform and Zero-Padding Aliasing Properties

Privacy is an important freedom, and in the modern world of technology, the probability of our private data being comprised is more likely than in the days before computers since all of our data can be stored electronically and possibly accessed from an outside location. This paper presents a methodology for steganography based on hiding images in the Fourier domain of an image by using the properties of zero-padding an image with itself causing aliasing to occur. Seventy-five percent of the resulting spectrum before any data is embedded in the image, has the value of zero. These zeros can be changed slightly where the change in the image is not noticeable. The data changes due to formatting an image in a 24-bit color format. This change can be accounted for using a transfer function which would also be needed to decrypt the information. The reason for this approach comes from the flexibility in the amount of data which can be hidden in an image and the location of the hidden data. The proposed method would also be advantageous in the manner that a person would need four images and a transfer function or a key so to speak, to recover the data. They would also have to know what order to put the four images before decryption can occur. This adds a level of complexity to steganography which can help to insure the data being sent is kept private