Đang chuẩn bị liên kết để tải về tài liệu:
Lecture Steganography: Introduction - Ho Dac Hung

Lecture Steganography: Introduction of Mr. Ho Dac Hung provides problem messages, covers objects, cryptosystems, steganographic keys (stego key), steganography throughout history, and modern steganography. Download this lecture to see more. | Introduction Ho Dac Hung 1 Contents Problem Steganography throughout history Modern steganography 2 1. Problem My friend Bob until yesterday I was using binoculars for stargazing. Today I decided to try my new telescope. The galaxies in Leo and Ursa Major were unbelievable Next I plan to check out some nebulas and then prepare to take a few snapshots of the new comet. Although I am satisfied with the telescope I think I need to purchase light pollution filters to block the xenon lights from a nearby highway to improve the quality of my pictures. Cheers Alice. 3 1. Problem Message Cover object Crypto systems Steganographic key stego key 4 1. Problem Steganography can be informally defined as the practice of undetectably communicating a message in a cover object. 5 2. Steganography throughout history The word steganography is a composite of the Greek words steganos which means covered and graphia which means writing . 6 2. Steganography throughout history In other words steganography is the art of concealed communication where the very existence of a message is secret. 7 2. Steganography throughout history 8 2. Steganography throughout history Hiding messages in text is called linguistic steganography or acrostics. Acrostics was a very popular ancient steganographic method. To embed a unique signature in their work some poets encoded secret messages as initial letters of sentences or successive tercets in a poem. 9 2. Steganography throughout history 10 2. Steganography throughout history Francis Bacon described a precursor of modern steganographic schemes. Bacon realized that by using italic or normal fonts one could encode binary representation of letters in his works. 11 2. Steganography throughout history A modern version of this steganographic principle was described by Brassil. He described a method for data hiding in text documents by slightly shifting the lines of text up or down by 1 300 of an inch. 12 2. Steganography throughout history In 1857 Brewster .