What it is
XChaCha20-Poly1305 is the authenticated-encryption algorithm Stax Pass uses to protect saved records. It keeps the contents private and helps detect unwanted changes.
How it works
It combines two jobs. XChaCha20 turns readable information into unreadable ciphertext using a secret key and a one-time value. Poly1305 then adds a small authentication tag so the app can tell if protected data was changed.
What it means for Stax Pass
In Stax Pass, XChaCha20-Poly1305 runs on your device before records are synchronized. The service is designed to receive protected data rather than a readable password list.
In Stax Pass, this protection applies before a saved password, private note, or supported file is synchronized. The service can keep the encrypted record available across your devices, but the readable version is intended to exist only after your authorized device unlocks it. This does not stop someone from seeing a password if they have already unlocked your device or if you enter it into a phishing site.
What it means for you
The practical takeaway is simple: a password manager should encrypt your saved logins before they sync, not merely hide them behind a website sign-in. You do not need to operate the cryptography yourself; your role is to protect your Stax Pass password and recovery phrase, and stay alert to scams.