Showing posts with label Cryptography. Show all posts
Showing posts with label Cryptography. Show all posts

Monday, September 1, 2008

In literature, a red herring is a narrative element intended to distract the reader from a more important event in the plot, usually a twist ending.



The term "red herring" originates from the tradition whereby young hunting dogs in Britain were trained to follow a scent with the use of a "red" (salted and smoked) herring (see kipper). This pungent fish would be dragged across a trail until the puppy learned to follow the scent. Later, when the dog was being trained to follow the faint odor of a fox or a badger, the trainer would drag a red herring (which has a much stronger odor) across the animal's trail at right angles. The dog would eventually learn to follow the original scent rather than the stronger scent.

In literature, the most commonplace use of a "red herring" is in mystery fiction. One particular character is described or emphasized in a way that seems to throw suspicion upon that character as the person who committed the crime: later, it develops that someone else is the guilty party.

This is used in cryptography as well!

In cryptography, a red herring is a second hidden message that is intended to be discovered more easily so that the real message remains hidden to anyone who might intercept the transmission and break the red herring code. Only the intended receiver would know the key to unlocking the real message.

Sunday, January 27, 2008

Last week I had my department function(virtuoso).It was really cool and I worked for 2 events in the function.One was best manager and the other was Project presentation.Project presentation was my favourite and it was rocking.One of the project presented there was steganography.This term was relatively new to me.But my senior informed me that it was a very common project and it was used by Osama Bin Laden!!!This kindled interest in me to find more on this subject.This post contains some nice information on steganography such that,even a novice could understand!!!

Steganography is the art and science of writing hidden messages in such a way that no one apart from the sender and intended recipient even realizes there is a hidden message. By contrast, cryptography obscures the meaning of a message, but it does not conceal the fact that there is a message. Today, the term steganography includes the concealment of digital information within computer files. For example, the sender might start with an ordinary-looking image file, then adjust the color of every 100th pixel to correspond to a letter in the alphabet -- a change so subtle that no one who isn't actively looking for it is likely to notice it.


Image of a tree.
By removing all but the last 2 bits of
each color component, an almost
completely black image results. Making
the resulting image 85 times brighter
results in the image below.


Image extracted from above image.

Generally, a steganographic message will appear to be something else: a picture, an article, a shopping list, or some other message. This apparent message is the covertext. For instance, a message may be hidden by using invisible ink between the visible lines of innocuous documents.
The advantage of steganography over cryptography alone is that messages do not attract attention to themselves, to messengers, or to recipients. An unhidden coded message, no matter how unbreakable it is, will arouse suspicion and may in itself be incriminating, as in countries where encryption is illegal.Often, steganography and cryptography are used together to ensure security of the covert message.

Steganography used in electronic communication include steganographic coding inside of a transport layer, such as an MP3 file, or a protocol, such as UDP.