The Laws of Cryptography:
Cryptograms and Terminology

by Neal R. Wagner

Copyright © 2002 by Neal R. Wagner. All rights reserved.

NOTE: This site is obsolete. See book draft (in PDF):

Law CRYPTO1a: Cryptography reduces the problem of keeping an arbitrarily long message secret to the problem of keeping a short key secret. What an impressive improvement!

Law CRYPTO1b: Cryptography reduces the problem of keeping an arbitrarily long message secret to the problem of keeping a short key secret. This is little if any improvement, since the problem of keeping something secret still remains.

Law CRYPTO2: Cryptography is the only means of securing the transmission of information where the cost is independent of the distance.

Law CRYPTO3: The method or algorithm of a cryptosystem must not be kept secret, but only the key. All security must reside in keeping the key secret.

Law CRYPTO4: Ordinarily an algorithm that only occasionally works is useless, but a cryptanalysis algorithm that occasionally works makes the cryptosystem useless.


Revision date: 2001-05-22. (Please use ISO 8601, the International Standard.)