Pay $0.02 USDC to store an encrypted secret (up to 100 KB). Encrypted with AES-256-GCM; key derived from passphrase via scrypt. The passphrase is never stored — only the ciphertext. Reveal with POST /secret/{token} and the correct passphrase. Network: Base Mainnet. Each request encrypts one secret for later reveal with the token and passphrase, making it useful for API key handoff, credential sharing, and agent-to-agent secret exchange.