|Operating system||Windows, macOS, Android, iOS, Windows Phone, Linux|
|Available in||English, French, German, Hungarian, Spanish|
Tresorit is an online cloud storage service based in Switzerland and Hungary that emphasizes enhanced security and data encryption for Businesses and individuals/freelancers. The Business version offers up to 1TB of storage space per user (the Solo version offers 2TB for one user) and extra security features such as DRM, granular access levels and other functions which aim to create a safer collaborative environment. Tresorit has been likened to a high-security alternative to Dropbox.
Tresorit's service is accessible through client desktop software, web-based application and mobile apps. Currently, the software is available for Windows, macOS, Android, Windows Phone 8, iOS, and Linux.
In August 2015, Wuala (owned by LaCie and Seagate), a pioneer of secure cloud storage, announced it was closing its service after 7 years, and recommended their users to choose Tresorit as their secure cloud alternative.
By the end of 2016, Tresorit launched a beta of the software development kit (SDK) ZeroKit. In January 2017, Apple's SDK project CareKit announced the option for mobile app developers using CareKit to integrate ZeroKit, enabling zero knowledge user authentication and encryption for medical and health apps.
"Tresors" (German for safes) are encrypted counterparts of uploaded directories. Tresors automatically sync with the cloud as files are added or removed from them, similar to Box.com and Dropbox's desktop software. The main difference between Tresorit and its competition is that Tresorit applies AES-256 client-side encryption to files while they are still local and then uploads them to the cloud. The company claims that due to its end-to-end encryption, users can share protected files and folders with others and work together on them, keeping the documents synced and secure in every step of the process. There are additional layers of security, but the core privacy feature of the service is that the encryption key never leaves the user: Using Zero-Knowledge encryption protocols, Tresorit is not in possession of the users’ authentication data, so the content of files cannot be accessed from their servers nor delivered to authorities upon request.
In 2013 and 2014, Tresorit hosted a hacking contest offering $10,000 to anyone who hacked their data encryption methods to gain access to their servers. After some months, the reward was increased to $25,000 and later to $50,000, challenging experts from institutions like Harvard, Stanford or MIT. The contest ran for 468 days and according to the company, nobody was able to break the encryption. 
Tresorit has received a number of nominations and awards. Up-Cloud Rewards named it one of the top 5 Cloud security solutions for 2012. Early 2016, Forbes listed Tresorit's cofounder Istvan Lam among the European "30 under 30". In 2017, Tresorit was listed as finalist in the Cybersecurity Excellence Awards, category Encryption.
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- Get 50GB of Free, Encrypted Online Storage from Tresorit
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- Hungarian ‘security freaks’: Hack our startup and we’ll give you $25K
- Hackers, Here's a Way To Make An Easy $25k
- Secure cloud firm Tresorit boosts hacker bounty to $25,000
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- awards | UP 2012 - Cloud Computing Conference 2012
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