Proton Lumo AI Assistant

Lumo is an advanced, privacy-centric AI assistant developed by Proton, the Swiss company renowned for its end-to-end encrypted services like Proton Mail. Launched in the summer of 2025, Lumo distinguishes itself through a unique 'user-to-LLM' encryption model. This architecture ensures that user prompts are encrypted on their local device using a hybrid AES-GCM and PGP scheme before being transmitted, meaning even Proton cannot read the contents of the conversations.

Technically, the product is maintained and operated from Switzerland, adhering to strict Swiss privacy laws. The brand is built on a foundation of open-source transparency, with much of its cryptographic logic available for public audit. It represents a significant step in the evolution of generative AI by prioritizing data sovereignty and cryptographic integrity alongside conversational intelligence. Lumo is owned and operated by Proton AG, a company founded by scientists who met at CERN with the mission of building a more private internet.