Encryption without encryption - from Ron Rivest

In a paper entitled "Chaffing and Winnowing: Confidentiality without
Encryption," Ron Rivest describes a method of transmitting a document
that gives an evesdropper no information about the content of the
document. <http://theory.lcs.mit.edu/~rivest/chaffing.txt>

"Winnowing does not employ encryption, and so does not have a``decryption key.''  Thus, the usual arguments in favor of ``keyrecovery'' don't apply very well for winnowing.  As usual, the policydebate about regulating technology ends up being obsoleted bytechnological innovations.  Trying to regulate confidentiality byregulating encryption closes one door and leaves two open(steganography and winnowing)."

Martin Minow
minow@apple.com