# Mathematical Digest

### Short Summaries of Articles about Mathematics

in the Popular Press

"Delicate information," by Rainer Blatt, *Nature,* 23 August 2001.

Blatt reaffirms that "Moore's law"---which simply states that processor speed,and hence computational power, doubles roughly every 18 months---has provedvalid over the past three decades. But he recounts how Peter Shor of AT&T cameup with a "stunning" algorithm in 1994. Shor showed that the factorization oflarge numbers---an extremely difficult and time-consuming problem for classicalcomputers---can be achieved in a highly efficient, rapid way using a quantumcomputer. Large numbers and their prime factors are commonly used to encryptdata and messages, as it takes too long to factorize a large number---and thusdecode the information---on a classical computer. If the factorization problemcould be solved, then all current cryptographic systems would be seriouslyendangered. Peter Shor's result therefore spawned a worldwide attempt to createa real quantum computer, which could be applied to basic research andtechnology. Blatt states that at this point quantum computers are able tohandle factorization and run a few other algorithms faster than the classicalworkhorses of information processing but that current research in quantumcomputation will serve as fundamental building blocks for tomorrow's generalquantum technology---that "quantum engineering may be the key technology of thetwenty-first century."

*--- Annette Emerson*