Sounil Yu is the co-founder and Chief AI Safety Officer at Knostic, best known for creating the Cyber Defense Matrix and the DIE Triad, two frameworks reshaping how the industry tackles cyber risk. His past roles span CISO at JupiterOne, CISO-in-Residence at YL Ventures, and Chief Security Scientist at Bank of America, building on earlier work with multiple Fortune 100 companies and federal agencies. He remains one of the field's most cited thought leaders with 20-plus patents and honors from the SANS Lifetime Achievement Award to a Cybersecurity Hall of Fame induction.