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Your LLM API key is stored server-side with envelope encryption so recruiters can chat with your bot at any time, even when your browser is closed. This page explains exactly what “envelope-encrypted” means and what a database leak would (and wouldn’t) reveal.

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Envelope encryption

Rather than a single static secret, ProBot uses two keys stacked:
  1. A KEK (Key Encryption Key) - a 32-byte symmetric key - lives only in the PROBOT_KEY_ENCRYPTION_KEY environment variable. Never in the database, never in git, never in a DB backup.
  2. A fresh DEK (Data Encryption Key) is generated per bot. The DEK encrypts your LLM key with AES-256-GCM.
  3. The DEK is itself encrypted (“wrapped”) with the KEK and stored next to the ciphertext.
  4. At chat time the server loads the ciphertext + wrapped DEK, unwraps the DEK with the KEK, decrypts your key, calls the provider, and discards everything from memory.

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Why this matters

A database dump, a SQL-injection read, or a stolen backup yields only ciphertext and a wrapped DEK - both useless without the KEK, which isn’t in the database. To rotate, change the KEK and re-wrap; the underlying LLM key never has to be re-entered if you script the re-wrap. When you self-host, you own the KEK, so even the managed operator cannot decrypt your stored key. See Managed vs self-hosted.