Difference Between Cryptography and Steganography

Cryptography is a method of hiding information in a particular form so that only the sender and intended recipient can read and understand it. Steganography is the method of hiding information within another non-secret document, image, video, etc. Though theses two terms seem to have the same meaning, they are actually two different concepts. Therefore, we are going to discuss the difference between Cryptography and Steganography.

What is Cryptography?

Cryptography is a method of storing and transmitting data in a particular form so that only the intended recipients can read and process it. In cryptography, the message or communication is obscured so that it cannot be understood by another party.

The term cryptography is derived from the two Greek terms ‘kryptós’ and ‘graphein’ meaning hidden and writing respectively. The origin of cryptography dates back to 2000BC, with the Egyptian practice of hieroglyphics. The first know modern use of cryptography was by Julius Ceaser, who communicated with his governors through secret messages.

In modern day, it is mostly used in the fields of computer science, mathematics and engineering. In modern cryptography, there are three types of cryptographic algorithms: Symmetric key cryptography, Public-key cryptography and hash functions.

The origins of cryptography dates back to 2000 BC , with the Egyptian practice of hieroglyphics.

What is Steganography?

Steganography is a method of concealing messages or information within a non-secret document or another medium. In Steganography, since the message is hidden inside another message or communication, there is no way of knowing that a secret communication is taking place. It is accurate to say that it is a method of sending a secret message in such a way that no one except the sender and the intended recipient knows that communication is taking place.

The term Steganography is said to be derived from the two Greek terms, steganós (cover, roof) and graphien (writing).The first ever recorded use of the term was by Johannes Trithemius in his book Stegnographia(1499)  a discourse on cryptography and Steganography, which was disguised as a book of magic.

Traditional uses of Steganography include using invisible ink in letters, messages hidden in body tattoos, newspaper adds, microdots, microdots, spread spectrum radio communications. Modern Steganography (Digital Steganography) includes the concealment of secret messages in computer files. Its modern methods include concealing messages within the lowest bits of noisy images or sound files, modifying the echo of a sound file, chaffing and winnowing, concealing data within encrypted data, making the text the same color as the background in word processor documents, e-mails, and forum posts, etc.

Example of Steganogrphy : image of the tree is the original image. Image of the cat is extracted from this image.

What is the difference between Cryptography and Steganography?

Concealment

Cryptography: In cryptography, only the secret message is hidden.

Steganography: In Steganography, the message, as well as the fact that a secret communication is taking place, is hidden.

Attention

Cryptography: Secret message might arouse interest of unwanted parties though data cannot be processed.

Steganography: Intended secret message does not attract the attention of unwanted parties.

Image Courtesy:

“Steganography original” by The original uploader was Cyp at English Wikipedia – Transferred from en.wikipedia to Commons by Sfan00_IMG using CommonsHelper. (CC BY-SA 3.0) via Wikimedia Commons

“Steganography recovered” by The original uploader was Cyp at English Wikipedia – Transferred from en.wikipedia to Commons by Sfan00_IMG using CommonsHelper. (CC BY-SA 3.0)via Wikimedia Commons