To hide this reasoning while maintaining conversational context across multiple API turns, major providers such as Anthropic and OpenAI use Authenticated Encryption with Associated Data (AEAD) envelopes. AEAD is a cryptographic standard that encrypts data while attaching metadata to verify that the payload has not been modified in transit.

Providers designed these encrypted envelopes around three goals:

1. Confidentiality: Prevent clients from reading the intermediate reasoning tokens to protect proprietary information.