Why Login Isn't Enough: Cryptographic Intent Verification for AI Agents

Most authentication systems solve the wrong problem. They verify identity at login — "are you who you say you are?" — then trust every action that follows. That worked fine when humans were the only ones taking actions. It breaks down fast when AI agents are involved. The gap nobody talks about An agent logs in with valid credentials. It has a valid session. It makes a request to transfer $50,000 to an external account. Every auth check passes. The action executes. Was that supposed to happen? N