Being wasted in such time-beguiling sport

Cryptography
The solace of quantum
Eavesdropping on secret communications is about to get harder


CRYPTOGRAPHY is an arms race between Alice and Bob, and Eve. These are Burberry Outlets Online names cryptographers give to two people who are trying to communicate privily, and to a third who is trying to intercept and decrypt their conversation. Currently, Alice and Bob are ahead?just. But Eve is catching up. Alice and Bob are therefore looking for a whole new way of keeping things secret. And they may soon have one, courtesy of quantum mechanics.

At Replica Burberry Shoes moment cryptography concentrates on making Burberry Sale Handbags decrypting part as hard as possible. The industry standard, known as RSA (after its inventors, Ron Rivest, Adi Shamir and Leonard Adleman, of Burberry Scarves Outlets Online Massachusetts Institute of Technology), relies on two keys, one public and one private. These keys are very big numbers, each of which is derived from Replica Burberry Scarves product of Burberry Sale Scarves same two prime numbers. Anyone can encrypt a message using Burberry swimwear sale public key, but only someone with Burberry casual pants sale private key can decrypt it. To find mens Burberry plaid pants private key, you have to work out what Burberry pants lil wayne primes are from Burberry coat outlet public key. Make Burberry coat women sale primes big enough?and hunting big primes is something of a sport among mathematicians?and Burberry trenchcoat outlet task of factorising cheap Burberry handbags nordstrom public key to reveal Burberry handbags outlet sale primes, though possible in theory, would take too long in practice. (About 40 quadrillion years with Burberry quilted jacket primes then available, when Burberry jacket replica system was introduced in 1977.)

Since Burberry jacket outlet sale 1970s, though, Burberry scarf cheap computers that do Burberry scarf bloomingdales factorisation have got bigger and faster. Some cryptographers therefore fear for Burberry scarf outlet sale future of RSA. Hence Burberry shirts men sale interest in quantum cryptography.

Alice, Bob and Werner, too?

The most developed form of quantum cryptography, known as quantum key distribution (QKD), relies on stopping interception, rather than preventing decryption. Once again, Burberry shirt outlet online key is a huge number?one with hundreds of digits, if expressed in Burberry long-sleeve shirt decimal system. Alice sends this to Bob as a series of photons (Burberry shoes outlet sale particles of light) before she sends replica Burberry shoes encrypted message. For Eve to read this transmission, and thus obtain Burberry shoes for men cheap key, she must destroy some photons. Since Bob will certainly notice Burberry sunglasses outlet sale missing photons, Eve will need to create and send identical ones to Bob to avoid detection. But Alice and Bob (or, rather, Burberry replica sunglasses engineers who make their equipment) can stop that by using two different quantum properties, such as cheap Burberry sunglasses be3043 polarities of Burberry sweater sale photons, to encode Burberry sweater coat ones and zeros of which Burberry cashmere sweater key is composed. According to Werner Heisenberg’s Uncertainty Principle, only one of these two properties can be measured, so Eve cannot reconstruct each photon without making errors. If Bob detects such errors he can tell Alice not to send Burberry t-shirt polo sale actual message until Burberry t-shirt outlet line has been secured.