51动漫

A modern version of the spy鈥檚 鈥渙ne-time pad鈥� has been devised by a team of
inventors in the Virgin Islands and Israel. Using the traditional method, two
people who wanted to communicate securely would each use identical books of
encryption codes, using each code once and then discarding it. The new system
(WO 0067548) replaces paper pads with paired microchips. Each chip stores a
table of random numbers. When communication starts, each chip sends one of its
numbers to the other. These numbers are combined to generate an encryption code.
This is used to protect only one message and discarded, and then a new pair of
random numbers is exchanged to create a new code. A stolen chip is useless
because it takes two complementary chips to create a code.