# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Crucial Cipher Flawed, Cryptographers Claim," by Charles Seife. *Science,* 27 September 2002, page 2193.

Nicolas Courtois and Josef Pieprzyk say that the recently-adopted Advanced Encryption Standard "has a hole in it." They claim that their attack reduces the number of operations required to beat the standard. The attack is based on rewriting their "S-boxes" (elements that add unpredictability to many encryption algorithms). The article offers two reasons why the new attack may not be any reason to be alarmed. One is that another cryptographer, Don Coppersmith, says that Courtois and Pieprzyk may have miscounted the number of equations in their attack. The other reason is that even if the number of equations is correct, the number of operations involved is on the order of 2^{100}, so the attack can neither be carried out nor verified in a reasonable time by today's computers.

*--- Mike Breen*