'Steganography' is not specifically a technique, but a general practice of concealing a message within other message. The hidden message appears not gibberish (as it does in cryptography), but appears to be something else.
Some classical techniques to hide a message in the plainsight were:
Use of invisible ink, Creating a puzzle, Clever arrangement of words of the original message into another text message (see the 'demo'), etc.
In modern world, digital steganography techniques is used to hide files, messages, images, documents or videos into another files, messages, images, documents or videos. Most of such techniques work by hiding the 'bits' of original message/file into the 'bits'-representation of the 'cover'-message/file. Some examples can be concealing messages within the lowest bits of 'noisy' images or sound files; Pictures embedded in the video material; Making text as the same color as the background in a document/blog; etc.
Indeed there are numerous ways to use steganography to hide a message or a file, and much depends on exploring new possibilities of creativity.
note: Don't forget to check out the text steganography puzzle in other tab. This is a popular puzzle (for Inspector Morse in the story) from the crime novel The Silent World of Nicholas Quinn, by Colin Dexter.
Till now we discussed either creative hiding of message (as in steganography) or encrypting of text by substituting letters. In the next post, we will discuss the a cipher which literally 'scrambles' (i.e. change the positions of) all the letters of the original message, based on some method.
Bye till then.
Greetings to all at Oxford. Many thanks for your
letter and for the Summer examination package.
All Entry Forms and Fee Forms should be ready
for final despatch to the Syndicate by Friday
20th or at the very latest, I'm told, by the 21st.
Admin has improved here, though there's room
for improvement still; just give us all two or three
more years and we'll really show you! Please
don't let these wretched 16+ proposals destroy
your basic O and A pattern. Certainly this
sort of change, if implemented immediately,
would bring choas.