The term Steganography is the technique of sending data in a concealed format so the very fact of sending the data is disguised. In the context of computer science, it refers to hiding data within a message or file. The word steganography is a combination of the Greek words steganos (meaning hidden or covered or concealed) and root graph (meaning to write, thus translating to ‘covered writing’, or ‘hidden writing’). The first recorded use of the term was in 1499 by Johannes Trithemius. However, traces of steganography already existed in ancient Greece. One example was having a secret message tattooed on a soldier’s shaved scalp. When hair grew back, he was dispatched on his mission. The receiver shaved the messenger’s scalp again and read the message. One other simplest example of this 21st century is the "Invisible ink". A person can write a message with clear or invisible ink that can only be seen when another ink or liquid is applied to the paper.
In digital steganography, there are many ways to conceal information, including embedding sensitive information into file types, one of the most common techniques is to embed a text file into an image file. When this is done, anyone viewing the image file should not be able to see a difference between the original image file and the encrypted file; this is accomplished by storing the message with less significant bytes in the data file. This process can be completed manually or with the use of a steganography tool.