Chaffing and Winnowing

Related Concepts

Pseudonymity; Unlinkability

Definition

Chaffing and winnowing is an encryption technique using no decryption keys. Although the technique is not efficient, it is perfectly practical.

Background

Chaffing and winnowing introduced by Ron Rivest [3] is a technique that keeps the contents of transmitted messages confidential against eavesdroppers without using encryption. Chaffing and winnowing was meant as a liberal statement in the debate about cryptographic policy in the 1990s as to whether law enforcement should be given authorized surreptitious access to the plaintext of encrypted messages. The usual approach proposed for such access was “key recovery,” where law enforcement has a “back door” that enables them to recover the decryption key. Chaffing and winnowing was proposed to obsolete this approach of key recovery because it reveals a technique of keeping messages confidential without using any decryption keys. The chaffing and winnowing technique was not invented...