If you’ve picked up a newspaper in the last two weeks, you’ve probably read something about digital encryption. It’s at the heart of the debate between the FBI and Apple: Can the government compel the company to break the encryption in one of its phones? That argument makes this year’s A.M. Turing award, often referred to as the Nobel Prize of computing, particularly apt.
The two winners announced yesterday, Whitfield Diffie and Martin Hellman, are two of the most important figures in the history of encryption. Together, they wrote a seminal paper called “New Directions in Cryptography” in 1976 that laid the groundwork for public key cryptography, a concept central to how the Internet works. It's the secure "s" at the end of “http” that allows users to conduct financial transactions with confidence and trust that a person or place online is who or what you think it is.
Thanks to Diffie and Hellman’s work, the Internet has become a place of commerce and communication. Innovation online abounds, largely because it’s a safe place to exchange goods and services. “You use the math that’s written in their paper every day when you browse the web,” says security technologist Bruce Schenier. “Sure, there’s been enormous development in the past forty years, but their math is still keeping you safe. And that’s extraordinary.”
The idea behind public key cryptography, which is also sometimes called asymmetric encryption, is actually kind of simple, even if the math is hard. Think of a door key as symmetric encryption. Everyone who has the same key will be able to open the locked door. With asymmetrical, public key encryption, however, everyone has two sets of keys, a public key and a private key.
When a door is locked by someone using public key encryption, they can install a lock that will only open with a certain person’s private key (which no one else will have a copy of). The public key is used to encrypt, or lock, the data, while the private key is used to unlock it. You can make and give away endless copies of your public key. It’s what will allow secure data to be sent to you that only you can open. And it solves the problem of having to send keys over insecure channels in order to share or unlock information, allowing parties who have never before met to have an extremely secure exchange.
“Marty Hellman and Whit Diffie richly deserve this prize. Their main contribution was in recognizing the usefulness of a category of mathematical quirks,” says John Gilmore, co-founder of the Electronic Frontier Foundation. (Disclosure: This author has written for the EFF.) “These quirks were ‘trapdoor functions’ which are easy to compute in one direction, easy to compute in the other direction if you have some partial information, but hard to compute in the other direction if you don't.”
“If you had asked someone before Diffie and Hellman in 1976 if you could do this, they would have said don’t be ridiculous, that’s impossible,” says Schneier. “It was an invention that was formed outside the government and really formed academic cryptography, which is everything that keeps us secure online.”
The A.M. Turing Award, which has been given by the Association for Computing Machinery since 1966, is named after Alan Turing, the British mathematician and cryptographer who played a key role in breaking the German ciphers---instrumental in the victory of the allied forces in World War II.
It's is not only the most prestigious award in computing, it also comes with a huge cash prize---$1,000,000 huge, in large thanks to a donation from Google. Hellman and Diffie were announced as the winners yesterday at the RSA security conference in San Francisco.
Both recipients said they plan to leverage their winnings for political projects. Hellman, who is a long-time anti nuclear weapons activist, wrote in a blog post Tuesday that he plans to use his prize money to continue his advocacy and work on a book with his wife about processes towards world peace and sustainability. Diffie has championed for privacy online for decades, and he said at the RSA conference yesterday that he plans on using his winnings to work on a history of cryptography before many of the seminal figures in the field pass away.
Public key encryption is how the commercial Internet works. So if you plan to do any online shopping anytime soon, give a little thanks to Diffie and Hellman. Or take the opportunity right now: After all, they’re one of the reasons why you’re able to read this article.
