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Program ID: Innovation Anthology #413

Program Date: 08/02/2011

Program Category: Information Technology

Cryptography Breakthrough Produces Secure Key

PROGRAM #413 INTERVIEW WITH DR. WOLFGANG TITTEL

MP3: 6.2 MB
Time: 6:52 Minutes

Dr. Wolfgang Tittel is an associate professor with the Institute for Quantum Information Sciences in the Department of Physics and Astronomy at the University of Calgary. He holds an Industrial Research Chair in Quantum Cryptography and Communication sponsored by iCORE/Alberta Innovates Technology Futures, NSERC, and General Dynamics Canada.

Dr. Wolfgang Tittel

CC:  WOLFGANG, COULD YOU TELL ME FIRST OF ALL ABOUT WHAT THE AREA IS THAT YOU ARE ACTUALLY RESEARCHING AT THE UNIVERSITY OF CALGARY?

WT:  Okay.  What we have done is that we’ve developed a system which allows the distribution of secret keys.  And these keys can then be used to encrypt and decrypt sensitive messages.

What is special about our key distribution system is that they use tiny light particles called photons to send those keys.

And the particular nature, the quantum nature of these photons ensures that any attempts to eavesdrop during the transmission of the key, raises a flag and will be revealed.

This is different from any classic or any standard key distribution procedure where this flag is not being risen and eavesdropping cannot be revealed.

This makes our technology particularly secure.

And one more important thing is that a message that is encoded using such a key will always remain secure.  That is, it cannot be decrypted a few years later from now due to advances in code breaking knowledge or advancing technology.  That is important to safeguard information such as health records or governmental information over a long time.

CC:  WHAT IS THE LATEST BREAKTHROUGH THAT YOU’VE MADE?

WT:  What we have done now is that we have shown that we have a system that can work completely independently over a long time and send keys between the University and SAIT.  We’re collaborating with SAIT as well, there’s one part of our system which is installed at SAIT and the other part is installed at the University of Calgary.

We use the standard optical fibre, the fibres that everybody uses for phone calls for instance, we use the standard optical fibre to send these photons, to send these keys between the University and SAIT.

What is new is that our product right now, our technology now works and works reliably and so we connect these two institutions in a secure way.

CC:  WELL, HOW IS IT THAT YOU CAN DETERMINE AT THIS POINT THAT THIS IS GOING TO LAST INTO THE FUTURE, AS YOU MENTIONED BEFORE?

WT:  Yeah.  Let’s go step back and think about how classical encryption works.  I have a message, I have a key and I apply a mathematical algorithm to combine the message with the key.  Then I send you as the receiver the so-called cipher text.

Now an eavesdropper may not be able to decrypt the cipher text.  But what the eavesdropper could do is just to record the cipher text and then wait until he has a more powerful computer or a massive terra computer, maybe has a quantum computer or maybe the mathematics has done some progress and there is an algorithm to undo this encryption mechanism quickly.

And then he can go back, decrypt the message that he has recorded maybe five or ten years ago, the cipher text he has recorded five or ten years ago, and reconstitute the original message.  Sometimes secrets are sufficiently important that they have to be safeguarded for a long time like health records, like governmental information.

Our encryption mechanism is different.  If we have a secret key, and that is what our key distribution system does, then we can apply an encryption mechanism which is very, very simple but which can never be inverted.

Meaning even in five or ten years or even 50 years from now, even if we had a quantum computer, it is impossible to find out the original message in the cipher text if our quantum key is used and if the appropriate encryption mechanism is used which we did when we communicated with SAIT.

CC:  WELL, HOW DID YOU FIGURE THAT OUT?  HOW TO GET THIS SUPER SECRET KEY SO IT COULD NEVER BE UNLOCKED?

WT:  That’s a quality of quantum mechanics.  Something that we call the Heisenberg Uncertainty Relations--sounds complicated, is not so complicated.  It tells you that you can never measure all properties of a photon at the same time.

It’s like you want to measure the speed and the position of a car, you can pick one or the other but not both, and if you measure the speed of the car, it will move a little bit, it will be somewhere else.  Or if you measure where the car is at a particular moment, it will change its velocity.

This is a property that we do not have in classical physics, but we don’t observe in the classical world, but is a property that we have in the quantum world.

And it simply means, now applied to key distribution, if somebody tries to measure the key, meaning tries to measure a property of the photon that encodes the key, the key will change a little bit, the car moves from one place to the other, and this is something the receiver can realize, and he can also realize how much eavesdropping has been done.

And that is the flag, the additional property which allows us to figure out if the key has been corrupted due to transmission, in which case we would not use it for encryption.  Or if it has not been corrupted in transmission, in which case we would use it.

CC:  HOW CAN THIS BE APPLIED IN THE REAL WORLD?

WT:  It is already commercially available.  There are two or three companies worldwide that sell these kinds of systems.  The systems are not so complicated anymore.  The transmission link is either a sender telecommunications fibre which exists all around the world.  Or keys can also be just sent through free space.

Obviously then it shouldn’t rain or there shouldn’t be tree or mountain in the way it obviously would not work.  The technology is mature.  And as I said before, these systems are already commercially available.

CC:  WHAT DOES IT MEAN FOR YOU AS A RESEARCHER?

WT:  It means that there is a potential or there is the possibility to really generate a product that is relevant for or to address the need of society—that is the need for secure communication.  So that’s very nice for us.  It’s very pleasant thing to see that we do work on some things that are directly useful.

But it also means that given there are still a lot of things to improve, and they go all the way down to very fundamental physics that we can extend the overall range from very fundamental to very applied physics.   That is one of the things that I really enjoy in my job.

CC:  SO WITH THIS NEW TECHNOLOGY, IS THIS SOMETHING THAT IS SIMPLY APPLIED TO COMPUTERS OR CAN IT COVER THE BROAD RANGE.  WE’RE HEARING NOW ABOUT HACKING OF CELL PHONES AND THAT KIND OF THING.  DOES THAT TAKE CARE OF THAT PROBLEM?

WT:  Not fully but it will take care or it can take care of a part of it.  If you think about hacking into computers or hacking into cell phones, there are two things.  One is a firewall that is badly implemented and somebody can simply look from the outside into your computer and copy what is in your hard disk.  This problem is not something we can address.

But what we can address is that if I use my cell phone to send you a message, that nobody can access the message that I sent because it is encrypted and it is encrypted with a quantum key.  And it turns out that then nobody can pick up the message during transmission, decrypt it and read it.

It attacks one of the links in the overall chain that is required to be secure, secure communication.

CC:  THANK YOU VERY MUCH WOLFGANG.

WT:  You’re more than welcome.

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As Vice President, Research at the University of Alberta, Dr. Lorne Babiuk believes it is very important to support the social sciences. Art and music, he says, improve our quality of life. And social scientists anticipate public controversy, such as the introduction of new technologies like nanotechnology.

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