Remaining silent helped Calce gain maturity and perspective on his crimes. "I was extremely young when I committed the crimes and didn't think I was ready to deal with the media at the time. I didn't even fully understand what I had done myself. I knew from the technological perspective what I was doing, but in terms of the collateral damage, I had no idea," he said.

Over the years, however, he watched as hackers and fraudsters evolved. "When I was sitting back and not going public with anything, it was just getting a lot worse," he said. "The hacking industry is huge right now. That's why I decided to step forward and tell my story. The whole idea to write a book was to get a message across."

But Calce hasn't stopped attracting controversy.

Criticisms range from attacks on the media for giving a former criminal further publicity to debates within security and hacker communities on whether Calce's fame exceeds his abilities.

"There's a lot of haters out there," said Calce. "They don't like the fact that I did that when I was 15."