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Operating systemWindows, macOS, Android, iOS, Windows Phone, Linux
Available inEnglish, French, German, Hungarian
TypeCloud storage
LicenseProprietary software

Tresorit is a cloud storage service with end-to-end encryption.[1][2]

Founded in 2011, Tresorit closed an €11.5M Series B financing round in 2018 and was featured on FT1000 by Financial Times 2020[3] as the fifth fastest-growing cybersecurity company in Europe.

The software is available for Windows, macOS, Android, iOS, and Linux, and the company has released plugins for Gmail and Outlook. As of 2022, Swiss Post owns a majority stake in the cloud storage service. Tresorit works as an independent entity under Swiss Post.[4] The company has offices in Zurich, Switzerland; Munich, Germany; and Budapest, Hungary, employing around 100 people.


Tresorit was founded in 2011 by Istvan Lam (CEO), Szilveszter Szebeni (CIO) and Gyorgy Szilagyi (CPO). In the coming years, Andrea Skaliczki joined as CFO, Istvan Hartung as CTO and Arno van Züren as CSO. The company officially launched its client-side encrypted cloud storage service after emerging from its stealth beta version in April 2014.

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.[5] After some months, the reward was increased to $25,000 and later to $50,000, challenging experts from institutions like Harvard, Stanford or MIT.[6][7][8] The contest ran for 468 days and according to the company, nobody was able to break the encryption.[9]

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 its users choose Tresorit as their secure cloud alternative.[10]

In 2016, Tresorit launched a beta of the software development kit (SDK) ZeroKit.[11] 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.[12]

In 2017, Tresorit patented its shareable encryption technology in the US under no. US 9563783 B2, and LogMeIn co-founder Marton Anka joined Tresorit as an investor and advisor.[citation needed]

In 2019, Tresorit reached the number of 100 employees, and Tresorit improved its governance feature set with e-mail verification and detailed user reports.

In July 2021, Tresorit was acquired by the Swiss Post[13] to further expand its presence in its core German-speaking markets, including Germany, Austria, and Switzerland.


Tresorit uses AES 256 encryption.[14] With Tresorit's end-to-end encryption, every file and relevant metadata on user devices are encrypted with unique, randomly generated encryption keys. These keys are never sent to Tresorit's servers in an unencrypted format. Accessing files is only possible with a user's unique private decryption key.[citation needed]

Tresorit uses random keys for each file and random IVs for each version of a file. The company claims that two identical files look completely different after encryption, thus they cannot be compared or matched.[citation needed]

Due to its zero-knowledge system,[15] Tresorit does not store passwords, only the user can access his/her own password. Administrators of a business Tresorit account can reset passwords in exceptional cases but can never access those.[citation needed]


In 2017, Tresorit was named one of the Rising Stars at Deloitte's Technology Fast 50 Central Europe Award.[16] In 2019, Tresorit was named as a Global Leader in Cloud Computing at the Stratus Awards.[17] In 2020, Tresorit was named a 2020 Gartner Peer Insights Customers' Choice for Content Collaboration Tools[18] and was featured on FT1000 by Financial Times 2020 as the fifth fastest-growing cybersecurity company in Europe.[19]

See also[edit]


  1. ^ Pickavance, Mark; updated, David Nield last (21 May 2020). "Tresorit cloud storage review". TechRadar. Retrieved 17 December 2021.
  2. ^ Wisdom Sablah (3 August 2021). "Tresorit cloud storage review 2021". ITProPortal. Retrieved 17 December 2021.
  3. ^ Kelly, Maxine (2 March 2021). "FT 1000: the fifth annual list of Europe's fastest-growing companies". Financial Times. Retrieved 15 December 2021.
  4. ^ "Swiss Post acquires e2e encrypted cloud services provider, Tresorit". TechCrunch. 8 July 2021. Retrieved 31 March 2022.
  5. ^ "Secure cloud storage outfit Tresorit posts $10K hacker bounty – Tech News and Analysis". 11 April 2013. Retrieved 18 June 2013.
  6. ^ Hungarian ‘security freaks’: Hack our startup and we’ll give you $25K
  7. ^ Hackers, Here's a Way To Make An Easy $25k
  8. ^ Secure cloud firm Tresorit boosts hacker bounty to $25,000
  9. ^ "Farewell, Wuala! Pioneering secure storage shuts down, recommends Tresorit". 17 August 2015.
  10. ^ "Wuala cloud storage was shut down, offers Tresorit as a secure alternative". Retrieved 31 March 2022.
  11. ^ Hinchliffe, Emma (11 January 2017). "Apple's CareKit apps get enhanced security option". Mashable. Retrieved 15 December 2021.
  12. ^ Hintchliffe, Emma (11 January 2017). "Apple's CareKit apps get enhanced security option". Mashable. Retrieved 31 March 2022.
  13. ^ "Swiss Post acquires e2e encrypted cloud services provider, Tresorit". TechCrunch. 8 July 2021. Retrieved 15 December 2021.
  14. ^ "Files shared via Tresorit". Tresorit. Retrieved 17 December 2021.
  15. ^ "What is Zero-Knowledge Encryption?". Tresorit Blog. 20 May 2016. Retrieved 15 December 2021.
  16. ^ "Növekedési rangsor: magyar adatbányászok és adattitkosítók is a régiós élmezőnyben |". Forbes (in Hungarian). 13 October 2017. Retrieved 31 March 2022.
  17. ^ "Tresorit named a Global Leader in Cloud Computing". Tresorit Blog. 24 October 2019. Retrieved 15 December 2021.
  18. ^ "Tresorit Named a 2020 Gartner Peer Insights Customers' Choice". Tresorit Blog. 28 October 2020. Retrieved 15 December 2021.
  19. ^ Kelly, Maxine (2 March 2020). "FT 1000: the fourth annual list of Europe's fastest-growing companies". Financial Times. Retrieved 31 March 2022.