Client-side encryption

Client-side encryption is the cryptographic technique of encrypting data on the sender's side, before it is transmitted to a server such as a cloud storage service.[1] Client-side encryption features an encryption key that is not available to the service provider, making it difficult or impossible for service providers to decrypt hosted data. Client-side encryption allows for the creation of applications whose providers cannot access the data its users have stored, thus offering a high level of privacy.[1]

Applications utilizing client-side encryption are sometimes marketed under the misleading or incorrect term "zero-knowledge",[2] but this is a misnomer, as the term zero-knowledge describes something entirely different in the context of cryptography.

Details

Client-side encryption seeks to eliminate the potential for data to be viewed by service providers (or third parties that compel service providers to deliver access to data), client-side encryption ensures that data and files that are stored in the cloud can only be viewed on the client-side of the exchange. This prevents data loss and the unauthorized disclosure of private or personal files, providing increased peace of mind for its users.[1]

Current recommendations by industry professionals as well as academic scholars offer great vocal support for developers to include client-side encryption to protect the confidentiality and integrity of information. [3][4] [5]

Examples of services that use client-side encryption by default

• Tresorit[6]
• MEGA[7]
• Cryptee[8]
• Cryptomator[9]

Examples of services that optionally support client-side encryption

• Apple iCloud offers optional client-side encryption when "Advanced Data Protection for iCloud" is enabled.[10][11]
• Google Drive,[12] Google Docs,[12] Google Meet,[13] Google Calendar,[13] and Gmail[13] — However, as of Jul 2024, optional client-side encryption features are only available to paid users.[14]

Examples of services that do not support client-side encryption

• Dropbox[15]

Examples of client-side encrypted services that no longer exist

• SpiderOak Backup[16]

See also

• End-to-end encryption – the encryption of data between two different clients that are communicating with each other
• Homomorphic encryption

References

1. Tunio Gaffer (2015). "Why Client-Side Encryption Is the Next Best Idea in Cloud-Based Data Security". Information Security Today. Auerbach Publications. Archived from the original on January 16, 2016. Retrieved February 21, 2016.
2. "Spider Oak - Please stop describing your service as "Zero Knowledge" unless and ... | Hacker News". news.ycombinator.com. Retrieved 2018-07-16.
3. Deka, Ganesh Chandra (31 October 2014). "3 Security Architecture for Cloud Computing". Handbook of Research on Securing Cloud-Based Databases with Biometric Applications. IGI Global. ISBN 978-1-4666-6560-6. Retrieved 21 February 2016.
4. Tobias Ackermann (22 December 2012). IT Security Risk Management: Perceived IT Security Risks in the Context of Cloud Computing. Springer Science & Business Media. pp. 136–. ISBN 978-3-658-01115-4. Retrieved 21 February 2016.
5. "Communications of the Association for Information Systems 13:Article 24". Cloud Computing Sicherheit: Schutzziele, Taxonomie, Marktübersicht. Fraunhofer-Institut für Sichere Informationstechnologie SIT. 2009. ISBN 978-3-9813317-0-7. Retrieved 21 February 2016.
6. "What is Tresorit". support.tresorit.com. Tresorit. 2023. Retrieved Jul 8, 2024.
7. "Mega Security Whitepaper" (PDF). mega.nz. MEGA. 2022. p. 21. Retrieved Jul 8, 2024.
8. "Cryptee Security". crypt.ee. Cryptee. 2024. Retrieved Jul 8, 2024.
9. "Cryptomator Github". github.com. Cryptomator. 2024. Retrieved Jul 8, 2024.
10. "Apple advances user security with powerful new data protections". apple.com. Apple. 2022. Retrieved Jul 8, 2024.
11. "How to Enable Advanced Data Protection on iOS, and Why You Should". eff.org. EFF. 2023. Retrieved Jul 8, 2024.
12. "Client-side encryption and strengthened collaboration in Google Workspace". workspaceupdates.googleblog.com. Retrieved 2023-01-24.
13. "Client-side encryption for Gmail available in beta". workspaceupdates.googleblog.com. Retrieved 2023-01-24.
14. "About client-side encryption". apps.google.com. Retrieved Jul 8, 2024.
15. "Can I specify my own private key for my Dropbox?". dropbox.com. Retrieved Jul 8, 2024.
16. "SpiderOak Cross Clave". crossclave.com. SpiderOak Cross Clave. 2024. Archived from the original on May 15, 2024. Retrieved Jul 8, 2024.