Chaffing and winnowing is a cryptographic technique to achieve confidentiality without using encryption when sending data over an insecure channel; it was conceived by Ron Rivest. It can be viewed as a form of steganography. The German Lorenz cipher machine Cryptography or cryptology is a field of mathematics and computer science concerned with information security and related issues, particularly encryption and authentication. ... Confidentiality has been defined by the International Organization for Standardization (ISO) as ensuring that information is accessible only to those authorized to have access and is one of the cornerstones of Information security. ... In cryptography, encryption is the process of obscuring information to make it unreadable without special knowledge. ... Professor Ron Rivest Professor Ronald Linn Rivest (born 1947, Schenectady, New York) is a cryptographer, and is the Andrew and Erna Viterbi Professor of Computer Science at MITs Department of Electrical Engineering and Computer Science. ... Steganography is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message itself is not disguised, but the content is obscured. ...
The sender (Alice) sends several messages to the receiver (Bob); each message is unencrypted but authenticated with a message authentication code (MAC) whose secret key Alice shares with Bob. Only one of the messages is authentic, the other ones are bogus (called "chaff"). An eavesdropper will be unable to tell which messages are bogus and which are real (i.e. to "separate the grain from the chaff") since he cannot determine which messages are authentic. Bob uses the MAC to find the authentic messages and drops the "chaff" messages. This process is called "winnowing". The names Alice and Bob are commonly used placeholders for archetypal characters in fields such as cryptography and physics. ... The names Alice and Bob are commonly used placeholders for archetypal characters in fields such as cryptography and physics. ... A cryptographic message authentication code (MAC) is a short piece of information used to authenticate a message. ... A key is a piece of information that controls the operation of a cryptography algorithm. ... Eavesdropping is the intercepting and reading of messages and conversations by unintended recipients. ...
This technique lends itself especially to use in packet-switched network environments such as the Internet, where each message (whose payload is typically small) is sent in a separate network packet. One variant of the technique is to continuously send out packets to multiple recipients: the participants who get chaff simply ignore it; this helps protect against information leakage and traffic analysis. In computer networking and telecommunications, packet switching is a communications paradigm in which packets (messages or fragments of messages) are individually routed between nodes, with no previously established communication path. ... Information leakage happens whenever a system that is designed to be closed to an eavesdropper reveals some information to unauthorized parties nonetheless. ... Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. ...
The name of the technique is derived from agriculture: after a cereal crop is harvested and threshed it remains mixed together with fibrous chaff, and must be separated out by a step of winnowing. Chaff is the seed casings and other inedible plant matter harvested with cereal grains such as wheat. ... Wind winnowing is a method developed by ancient cultures for agricultural purposes. ...
Chaffing and winnowing is separation of chaff from grain, done by a threshing machine; the phrase is also used metaphorically.
Chaffing and winnowing is a cryptography technique, though as it works by hiding which part of a transmission is the message, it is classified as steganography.
A message is broken into blocks, and each one is transmitted with a message authentication code[?], interspersed at random with other similar blocks, called chaff.
Feeds |
Contact