Editing Chaffing and winnowing (section)

{{Short description|Cryptographic technique}}
{{refimprove|date=October 2009}}
'''Chaffing and winnowing''' is a [[cryptography|cryptographic]] technique to achieve [[confidentiality]] without using [[encryption]] when sending data over an [[insecure channel]]. The name is derived from agriculture: after grain has been harvested and [[threshing|threshed]], it remains mixed together with inedible fibrous [[chaff]].  The chaff and grain are then separated by [[winnowing]], and the chaff is discarded. The cryptographic technique was conceived by [[Ron Rivest]] and published in an on-line article on 18 March 1998.<ref name="ron">[https://people.csail.mit.edu/rivest/pubs/Riv98a.prepub.txt Rivest's article on chaffing and winnowing]</ref> Although it bears similarities to both traditional encryption and [[steganography]], it cannot be classified under either category.

This technique allows the sender to deny responsibility for encrypting their message. When using chaffing and winnowing, the sender transmits the message unencrypted, in clear text. Although the sender and the receiver share a secret key, they use it only for [[authentication]]. However, a third party can make their communication confidential by simultaneously sending specially crafted messages through the same channel.