An Overview of Steganography: “Hiding in Plain Sight”

Stegosystem Model

StegoSystem components are:

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  Cover File (Carrier): Is the host file into which the secret message is hidden. It is also known as innocent file or original file. (Archana, Antony, & Kaliyamurthie, 2013) (Shatha, Baker & Ahmed, 2013).

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  Secret Message (Payload): Is the massage that will be hidden within the carrier file. It can be plaintext, an image, or anything that can be represented as a bit stream (Shatha, Baker, & Ahmed, 2013) (Tayana, 2012).

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  Stegofile (Stego-Object): Is the resultant file obtained after hiding the payload into the carrier file.

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  Stegokey: Is an optional password that may be used to encode the secret message to increase the level of security (Shatha, Baker, & Ahmed, 2013) (Jack & Russ, 2007).

Actually, steganography is comprised of an embedding algorithm which concerned with embedding a secret message within a carrier file, and it is the most carefully constructed process, and an extraction algorithm which is much simpler process as it is an inverse of the embedding algorithm where the payload is extracted at the end.

The entire process of steganography can be presented in Figure 1. The inputs are passed through the encoder to embed the payload (secret message) within the carrier file. The system may require a key which is also used at the extraction phase. The resulting output from the system encoder is the Stegofile. This file is then sent over some communications channel along with the key (if used). Both the Stegofile and the key are then fed into the decoder where the secret message is extracted (Deepa & Umarani, 2013) (Saeed, Kabirul, &Baharul, 2013).

Figure 1.

Steganography History

This section will give some interesting insights and context into steganography by showcasing some of the prominent people, events, and methods used throughout history.