Sefi Attias is what some might call a geek. At the age of 14, he built a robot to walk behind him and schlep his books to school. In the army, he spent five years as an engineer in an electrical warfare development unit. And just last month, when the lanky, bespectacled 24-year-old Israeli wanted to propose to his girlfriend Tania, a petite 25-year-old cyber intelligence...