## Cryptography

#### The History and Mathematics of Codes and Code Breaking

While almost everything on Elonka Dunin’s website seemed very interesting, the one thing that stood out the most to me was her presentation on steganography. She goes into great detail on what exactly steganography is, and whether or not terrorists were truly utilizing steganography to spread hidden messages. Elonka found that to this date, Al Qaeda’s members have never utilized digital steganography to spread messages. Although there was great speculation and some instances that pointed to this being true, Elonka found no convincing evidence that this was the case.

Elonka also goes on to show interesting examples of steganography, such as the “sekrit” page. The page had numbers that translated into an ISBN number for the book “Disappearing Cryptography, which contained information on steganography. The page also featured anagrams and steganographically hidden small files, which contained information on opening a message hidden elsewhere in the code. She also showed numerous examples of modern steganography, especially hiding messages inside pictures.

After showing examples of steganography and how it is employed, Elonka detailed ways in which to defeat steganography. She highlighted the “Three D’s of Defeating Steganography” – Detection, Decryption, and Deletion. Detection involves examining an image for irregularities or changes in patterns. Decryption involves obtaining a password or information about how the message was encrypted. Finally, deletion involves cropping an image or changing an intercepted message in some way to remove the stegonographic image. Although you won’t be able to decipher it, the intended receiver will no longer be able to find the message either.

I enjoyed going through Elonka’s presentation as it presented a lot of cool information about steganography, which we haven’t been able to cover in depth in class. She covered various forms of steganography, how to beat it, and intriguing examples of steganography in use. Especially interesting were the various sites and programs that could create steganographically hidden messages for you, with the user only needing to provide the message. While the ciphers covered in class, such as the monoalphabetic and vigenère ciphers, were difficult but not impossible to beat, steganography could be a powerful way to protect information. If you have no idea where to look or how to begin, the message may easily skip past you without you even realizing a message was present.

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1. #### Parker

Since steganography does not fall under the category of cryptography, we have steered clear from this realm of hiding secrets, and besides the few paragraphs in “The Code Book”, we have not learned much about it.

Although I was not able to attend Elonka Dunin’s guest lecture, I have found her research very interesting. What I find most interesting though is her first “D” of her 3 “D”s to defeat steganography that Felix touches upon, detection.

In the history of cryptology, cryptographers and cryptanalysts have become increasingly reliant on technology to handle more secure ciphers. For example, the Enigma machine was created to create an “unbreakable cipher,” and, its later editions, can be considered practically unbreakable until certain technology was invented. It took Alan Turing to create his machine in order to finally crack the Enigma.

In much the same way, steganography was revolutionized with modern technology. With the advent of digital images, web pages, and digital audio files, steganography was able to progress very quickly. Like Felix mentions, now there are so many different computer programs that exist that can create stenographically hidden messages for you that can effectively create messages that are completely hidden to the naked eye/ear. However, there are also programs that have been created that can detect these messages as well so it is interesting to see the back and forth battle in steganography that parallels that of cryptography.

The information I am referencing comes from her online presentation at: http://elonka.com/stego/StegoLR.htm

• #### Derek

Good point, Parker. Just as technology has opened up new options for clever steganography, it’s also made detecting hidden messages easier. Nice comparison to the “arms race” between code makers and code breakers.