Paul Judge, 39
The Atlanta-based entrepreneur and computer science Ph.D. got his start as a spam email blocker. He joined junk-mail eradicator CipherTrust in 2000, rising to become chief technology officer. After the company’s sale to Honeywell spinoff Secure Computing, Judge founded PureWire, an Internet traffic scrubber that Barracuda Networks scooped up in 2009. Two years later he cofounded phone-fraud-fighter Pindrop Security. Now he leads Wi-Fi device maker Luma—and invests in startups like Amazon-backed data shielder Ionic Security.