C ONTENTS Defination Steganography History Steganalysis Steganography v/s Cryptography Steganography Under Various Media Steganographic methods Merits of Steganography Threats of Steganography Conclusion References
D EFINITION Steganography is the science of hiding information in such a way that no one suspects the information exists Steganography is a Greek word. Means concealed writing The purpose of steganography is covert communication to hide a message from a third party
Steganography hides the covert message but not the fact that two parties are communicating with each other. The steganography process generally involves placing a hidden message in some transport medium, called the carrier. The secret message is embedded in the carrier to form the steganography medium.
S TENOGRAPHY H ISTORY Steganography has been used since ancient Greece. Herodotus(485-525 BC) is a great historian. His great work, The Histories has a story which has used ancient stenography.
These messages were sent by the German embassy in World War I. This is called a null cipher. PRESIDENT'S EMBARGO RULING SHOULD HAVE IMMEDIATE NOTICE. GRAVE SITUATION AFFECTING INTERNATIONAL LAW. STATEMENT FORESHADOWS RUIN OF MANY NEUTRALS. YELLOW JOURNALS UNIFYING NATIONAL EXCITEMENT IMMENSELY. APPARENTLY NEUTRAL'S PROTEST IS THOROUGHLY DISCOUNTED AND IGNORED. ISMAN HARD HIT. BLOCKADE ISSUE AFFECTS PRETEXT FOR EMBARGO ON BYPRODUCTS, EJECTING SUETS AND VEGETABLE OILS. Taking the first letter in each word of message 1 or second letter in message 2 reveals the hidden text.
PERSHING SAILS FROM NY JUNE 1.
S TENOGANALYSIS Steganalysis is the art and science of detecting messages hidden using steganography. The goal of steganalysis is to identify suspected packages, determine whether or not they have a payload encoded into them, and, if possible, recover that payload.
S TENOGANALYSIS V / S C RYPTOGRAPHY With cryptography the information is known to exist, but it is encoded in such a way that only the intended recipient can read it. Steganography disguises the messages as something else, so the interceptor doesnt even know theres a message buried in there. The goal of cryptography is to make data unreadable by a third party.
The goal of steganography is to hide the data from a third party. EXAMPLE : Memo to the Director Subject: Letter of Recommendation - Jane S., a chief sub editor and editor, can always be found hard at work in her cubicle. Jane works independently, without wasting company time talking to colleagues. She never thinks twice about assisting fellow employees, and she always finishes given assignments on time. Often Jane takes extended measures to complete her work, sometimes skipping coffee breaks. She is a dedicated individual who has absolutely no vanity in spite of her high accomplishments and profound knowledge in her field. I firmly believe that Jane can be classed as a high-caliber employee, the type which cannot be dispensed with. Consequently, I duly recommend that Jane be promoted to executive management, and a proposal will be sent away as soon as possible. Project Leader
(Later that afternoon another memo was sent) Memo to the Director: Sorry about the earlier memo. Jane was looking over my shoulder as I wrote it. Kindly read every other line (i.e. 1, 3, 5, 7) for my true assessment of her. Regards, Project Leader HdlLQRPQdrmnWskKznOSarxq4GjpRTQo4hpCRJJ5aU7tZO9H PTZXFG6iRIT0wa47AR5nvkEKoIAjW5HaDKiJriuWLdtN4OXec WvxFsjR32ebz76U8aLpAK87GZEyTzBxdV+lH0hwyT/y1cZQ/E5 USePP4oKWF4uqquPee1OPeFMBo4CvuGyhZXD/18Ft/53YWIe bvdiCqsOoabK3jEfdGExce63zDI0==MpRf
This is a previous one is the perfect example of steganography. A message disguised as something else with a key (reading every other line) provided to expose the original message. The later one is the perfect encrypted form of cryptography.
S TEGANOGRAPHY UNDER VARIOUS M EDIA Steganography is not limited to the above examples of text. Steganography is also done in the various types of media. Steganography is done by hiding text in the bits of images. Steganography is done by hiding messages in audio files.
S TEGANOGRAPHIC M ETHODS The simplest and most common type of steganography is LSB (least significant bit). The ones bit of a byte is used to encode the hidden information. Suppose we want to encode the letter A (ASCII 65 or binary 01000001) in the following 8 bytes of a carrier file. 01011101 11010000 00011100 10101100 11100111 10000111 01101011 11100011 becomes 01011100 11010001 00011100 10101100 11100110 10000110 01101010 11100011
Is the difference between level 37,243 and 37,242 detectable by the human ear? Probably not. Typical.wav file uses 16 bit sampling.
M ERITS & U SES Digital Watermarking By using steganography user might acquire an embedded image. Secret message can be trans mitted without the fact that transmission was done. The more obvious uses of steganography relate to secret communications.
T HREATS It requires a lot of overhead to hide a relatively few bits of information. The hiding of malware into seemingly safe files such as pictures, audio and email attachments. This method is used to hide any type of malware ranging from viruses to worms from spyware to Trojans. An example was the Anna Kournikova virus which was sent via email as an attachment AnnaKournikova.jpg.vbs.
C ONCLUSION The objective of this paper was to demonstrate our Steganography, which is based on a property of the human visual system We are very convinced that this steganography is a very strong information security technique, especially when combined with encrypted embedded data. Always be aware while using technology it can be much more than what you can see.