Privacy Blog

"Friends don’t let friends get spied on.' – Richard Stallman, President of the Free Software Foundation and longtime advocate of privacy in technology.

Tresorit’s Super Secure Online File Storage

NOTE: This is an update to an article I published in 2015. Tresorit recently made some major updates to the service and this article reflects those changes.

The big news in technology these days is “the cloud.” In fact, the cloud offers many different services but the most common one for consumers is file storage. Companies like Dropbox, Google Drive, SugarSync, OneDrive, and others provide off-site backup services and also allow users to access their own files on desktop, laptop, and tablet computers or even on cell phones. The file storage business has skyrocketed in the past few years as consumers have learned how useful such services can be.

Many consumers are reluctant to trust these services, however. Real and imagined security concerns have made many people slow to adopt file storage technology. Most of the concerns revolve around access to personal information by hackers as well as by government hackers and by anyone outside the government who wishes to steal personal information and identities. Experience has proven that any file storage service in the U.S. will quickly provide any and all personal information to any law enforcement officer who shows up at the company’s door with a court order. That willingness to share is a valid concern for anyone who values privacy.

One company solves the problem. That company’s product encrypts all data on the consumers computer BEFORE it is sent to the company’s servers. Nobody, not even the company’s own employees, can read your data. In addition, the company is based in Switzerland and has all of its servers in that country or in the European Union. Both Switzerland and the European Union have very strong laws about protecting the privacy of individuals. Swiss laws forbid the release of personal information to any government agency, not even to the Swiss government. A court order from a US court is useless in Switzerland and in the European Union when the data is stored on servers there.

That company has the strange name of Tresorit.

Tresorit is incorporated in Switzerland and operates under Swiss laws, not under US laws and government edicts. Tresorit provides client-side security on all devices. The company is so confident of its security that it has offered a $50,000 prize to anyone who can hack in and obtain any private data from Tresorit’s servers. More than 1000 hackers have registered for the challenge and attempted to break Tresorit’s security to win $50,000. So far, no one has succeeded.

With Tresorit’s client software installed in your computer, tablet, or cell phone, you can edit and save any files, not just access files on your mobile devices. Information stored in the company’s servers is “zero-knowledge.” According to the Tresorit web site at

“Using end-to-end encryption, Tresorit encrypts every file and relevant file metadata on your devices with unique, randomly generated encryption keys. These keys are never sent to our servers in unencrypted format. Accessing files is only possible with a user’s unique decryption key.”

Yes, even the “relevant file metadata” is encrypted. Tresorit’s employees cannot even see the names or sizes of your files. If you save a file named MySecretStuff.doc or any other file name, Tresorit’s employees and any hackers who intercept your data while it is being sent across the Internet will only be able to see something that looks similar to this: umTnD4#,id;)jej.

The files are encrypted not only when on Tresorit’s servers, but even when being sent across the Internet to and from those servers. Quoting the web site again:

“Tresorit’s client-side encryption technology secures your files on your device with some of the highest grade encryption methods available and your files can’t be decrypted in the cloud. This makes them safer than “safe”. No one else has the decryption key, not even Tresorit administrators. Only you and those who you share with have access.”

You can learn a lot more about Tesorit’s cryptographic protection at

Tresorit not only keeps the current versions of your files, it also keeps the previous ten versions. This is a life saver when a file has been changed accidentally or if it became corrupted while on your own computer. It is easy to revert back to an earlier version of the file(s) in seconds.

Should you wish to do so, the Tresorit user may (optionally) share files with friends, co-workers, or business associates. Sharing includes several options, including the ability to grant full read-write power to others or to restrict their access to read-only permission. Your file(s) remains encrypted and unavailable to anyone to whom you have not given access permission.

With Tresorit, you can define when, where, and by whom your business data can be accessed so that you can keep control of confidential documents. Anyone with permission to access your file(s) may do so in a normal web browser. There is no need for them to install Tresorit software or to have a Tresorit account of their own.

You can read more about Tresorit’s file sharing at:

Tresorit’s recent updates includes protection against ransomware. The new File Restore option that helps users restore their confidential files and folders that are deleted due to a ransomware attack or simply by accident. The new feature works for items that are synced to local devices, too, providing a backup option for files that are deleted by ransomware. Ransomware is a growing security risk for businesses who are gearing up their data protection processes for the upcoming EU privacy regulation, the GDPR.  Unlike the file storage services available from most U.S. services, Tresorit’s service is fully GDPR compliant. (You can read more about the General Data Protection Regulation (GDPR) at: File Restore is also helpful when users accidentally delete an important business file or folder.

File Restore doesn’t have a time limitation, items can be restored with a simple click for as long as users don’t confirm to delete them permanently. The new feature is available both for Individual and Business users of Tresorit.

Tresorit software is available for Windows, Macintosh, Linux, Apple iOS, Android, Windows Phone, Blackberry and even from a web browser. Files uploaded with any version of Tresorit software can later be retrieved and read by any other version of Tresorit software. Unlike some other encrypted file storage services, the Tresorit software is very easy to use. You can see a side-by-side comparison of Tesorit’s services versus its major competitors at

This review only lists the major featires of Tresorit’s secure cloud storage services. There is a lot more information available at

Tresorit offers different pricing models for individuals, businesses, or enterprises. Pricing for individuals starts at $10.42 (US) per month and includes up to 200 gigabytes of encrypted file storage space. (A free trial is also available.) The encrypted storage space can (optionally) be shared and files can even edited by multiple users if the administrator gives the other users the required permissions.

Full pricing information for individuals, businesses, and enterprises may be found at:

Tresorit is based in Switzerland and accepts payments in Euros (EUR), US Dollars (USD), Swiss Francs (CHF), or British Pounds (£).

What level of protection do you want for YOUR personal files?

Tresorit provides industrial-grade security and protection for all your files, even the most sensitive ones. Unlike most of the US-based file storage providers, files stored in Tesorit’s servers can never be exposed to others, even if a court order is issued. You can learn more about Tresorit at

Categories: Cloud Services, Online Privacy & Security

1 reply

  1. Thank you very much for this great post. I’m using Tresorit myself and are really happy with it.

    Just one short remark:
    ‘That company has the strange name of Tresorit.’

    One of the languages official speaken in Switzerland is german and the german word “Tresor” means “vault”.


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