Somebody talked me into writing an autobiography about six or seven years ago. And I said I'd try. We talked into a tape recorder, and after a couple of months, I said, To hell with it. I was so depressed. It was like saying, 'This is the end.' I was more interested in what the hell was coming the next day or the next week.

I'm a strange mixture of my mother's curiosity; my father, who grew up the son of the manse in a Presbyterian family, who had a tremendous sense of duty and responsibility; and my mother's father, who was always in trouble with gambling debts.

If the sea level rises 6 inches, that's a big deal... we can't mitigate that; we can't stop it. We've just got to stop building vast houses on seashores and go back a little bit.

It's been a long career, and I've made some mistakes along the way.

Cryptography is the essential building block of independence for organisations on the Internet, just like armies are the essential building blocks of states, because otherwise one state just takes over another.

Now, with social media, it's a whole different world, which is good and bad. Back when I was in college, when there was no Twitter, no one knew what Vera Wang looked like - there was no face to the brand.

I think that everyone on the Internet has to deal with people saying negative things. It can be tough!

The world has become more complex as technology and easy travel mixes cultures without homogenizing them.