Proton has unveiled an end-to-end encrypted document editor that it said will provide an alternative to Microsoft Word and Google Docs for privacy-conscious users.

Docs in Proton Drive, announced on Wednesday by the Swiss software vendor that's best known for its encrypted email app, contains many of the document creation features that office workers might expect.

Users can create and edit documents, share with colleagues for real-time collaborative work, leave comments and replies, and import and export common file types such as .docx and .txt. The app is available in Proton Drive, an encrypted cloud storage service launched by the vendor in 2022.

But it's the end-to-end encryption rather than the document editing features that makes Proton's editor stand out from well-established alternatives on the market.

Only customers are given access to the end-to-end encryption keys, which means that any data entered into a document in Proton Docs is inaccessible by Proton, the company said. That includes keystrokes and cursor movements.

Privacy measures in Proton's Docs app contrast with the likes of Google Docs, which can "see everything you write and keep a record of all changes that you have ever made," said Anant Vijay, senior product manager for Proton Mail and Proton Drive, in a blog post.

"Once you provide your data to these companies, you no longer have control over how it is used," he said, citing growing concerns around the ability of software vendors to train their AI algorithms on customer data.

There's also the risk that data contained in documents could be accessed should a vendor's server be compromised.

Another advantage of Proton Docs, the company claims, is that user data is stored on Proton's cloud servers in Switzerland. Strict Swiss data privacy laws ensure that information stored on Proton's servers is not subject to access by government authorities in the EU or US, for instance.

The rollout of Docs to Proton Drive customers starts today, with the feature available to all users in the "next couple of days," Proton said. Proton Drive is available to consumers under a freemium model, with individual subscriptions costing up to E10 a month (currently about US$10.80) billed annually. Proton for Business subscriptions start at E7 per user per month.

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