Steganography

Steganography

Intro to Computer Forensics

CINS 139

April Payton

What is Steganography?

The word steganography comes from the Greek name “steganos” which means hidden or secret, and the word graphy, which means writing or drawing. Put them together, and it literally translates to mean “hidden writing” (Richer, 2010). According to Dictionary.com, steganography is “the art of writing in cipher, or in characters, which are not intelligible except to persons who have the key; cryptography.” In the modern use of the word, steganography means the practice of hiding messages within larger messages so that others cannot detect what the message contains, or even that the message is there. It replaces redundant bits in images or other media with secret information from the hidden message. The redundant bits are used because they can be changed without making a noticeable change in the image or sound file.

Steganography is a lot like cryptography, except there are some differences. Cryptography scrambles the message so that if someone discovers it, they cannot understand the contents of the message easily. A decryption key or password is required in order for the recipient to use the information. The goal of steganography is to have the message go through without anyone other than the intended recipient even knowing it was there. When steganography is used, the message is completely hidden, or invisible, so unless you know what to look for, you wouldn’t even know the hidden message is there. When cryptography is used, and noticed, it may make people suspicious, while when the message is hidden using stenography, it is invisible so as not to arouse suspicion.

Steganography is meant to s...

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... values of two files in a program. Investigators use the program to create a 128-bit fingerprint of the file, which enables fairly reliable identification of files using their hash value (Richer, 2010).

• Stegdetect and Xsteg. These programs are freeware. Stegdetect is reliable when used to detect JPEG images that contain hidden using JSteg, JPHide and OutGuess (Richer, 2010). It can also be used to perform brute-force attacks against JSteg and JPHide.

• StegoWatch from WetStone Technologies Inc. StegoWatch is different than the other software in that it can be used as an outsourced monitoring and scanning service, or as a software package that users can use to detect steganography. It examines images and uses a mathematical model to detect the steganographic images. Organizations can use it to scan their networks routinely for suspicious activities.