Abstract of the diploma thesis:
Digitial communication has become an essential part of modern life and therefore, in some cases, its use is desired to stay secret. There are two available techniques: cryptogtaphy and steganography. Cryptography is a techique that provides secret communication with encryption . Sometimes hiding just the message content is not enough, so we try to conceal entire existence of the message. The need for this resulted in the development of steganography. The explanation how steganography has been developed throughout the history and today's application of it is explained at the beginning of thesis. Then the steganography communication scheme and it's components are presented. The main goal of this thesis is to thoroughly explain the most common image-hiding techniques and comparative analysis is made to demonstrate the strong and weak points of the proposed methods. The comparison of the presented methods is performed by using methods for image quality evaluation: MSE (Mean Square Error) and PSNR (Peak Signal To Noise Ratio).