Lumo features a "Ghost" mode that makes the current conversation invisible after it is closed. A search function through search engines is also available, which maintains confidentiality. Users can link files from Proton Drive to Lumo, and they remain encrypted.

Access to Lumo is free through the website Lumo.proton.me — users do not need a Proton account to start using it. However, if an account exists, chat history can be stored using "zero-access" encryption across all devices.

For active users, a Lumo Plus subscription is available for $12.99 per month, which removes limits on the number of chats and file uploads. Proton's CEO, Andy Yen, emphasized that Lumo is designed to ensure AI does not become a tool for mass surveillance. "We believe it is important to offer an alternative that protects privacy and serves the interests of users rather than exploiting their data," he said.

The new chatbot is already available for download in the App Store and will be a valuable tool for those who value privacy in the digital world.