ASSYMETRICAL KEY

• The need for alternative to private key encryption
• Early Development of Alternative Key Exchange Mechanism
• Development of Asymmetrical Key Encryption

Early Development on Alternative Key Exchange Mechanism

In the early 1970’s, a variety of solutions to the problems of private key encryption began to roll out of, you guessed it, MIT, UC Berkeley, and Stanford, American higher education institutions. One attendee of UC Berkeley, Ralph Merkle who was taking a course in the fall of 1974 taught by Lance Hoffman (now a professor of computer science specializing in computer security at George Washington University in Washington D.C.). Merkle decided that for his term project he wanted to solve the problem of key exchange, and titled his proposal, "Secure Communication over Insecure Channels." Hoffman didn’t understand Merkle’s proposal and asked him to pick a different project. Merkle dropped Hoffman’s course and wrote the project for submission to Communications of the ACM, the premier computer science journal.

Merkle’s system works like this. David and Antonia need to send each other information about their ThinkQuest project, but some jealous teams want to know what their ideas are. David then makes a list of one million possible encryption keys, and hides each in a puzzle that takes two minutes to solve. Antonia takes one of those puzzles, solves it, and encrypts a block of zeros to send back to David. David then uses the one million keys to try to decrypt the block of zeros. Several minutes later, David and Antonia are safe to communicate. The other teams, however, see a million puzzles go by, an encrypted message go back, and that’s it. It’ll take the other teams an average of 500,000 puzzle solutions at a minute a puzzle to find the used key. By that time, David and Antonia would be on their way to Washington D.C. to accept their award for best web site.