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Zoho OneAuthProton Authenticator
Free

Free authenticator app.

 Free

Free and open source under the GPL, with no advertising. A Proton account is used for…

Windows, Android, iOS Windows, Linux, Android, iOS
  • Time-based one-time codes for third-party accounts
  • Passwordless and QR code sign-in for Zoho accounts
  • End-to-end encrypted sync between devices, which most free authenticators lack
  • Apps for Android, iOS, Windows, Linux and macOS
  • Many features apply only to Zoho accounts
  • Closed source
  • Sync requires a Proton account
  • Keeping codes on the same desktop you log in from weakens second-factor separation
Downloadable app Downloadable app
Closed source Open source
License not stated License: GPL-3.0
Not stated if an account is needed No account needed
Not stated if it works offline Works offline

Checked October 2, 2026

Checked September 21, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.