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. 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 zero-knowledge applications whose providers cannot access the data its users have stored, thus offering a high level of privacy.

Client-side encryption is widely recognized as an exceptionally robust data security strategy. By eliminating 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 both personal and business users.

Current academic scholarship as well as recommendations by industry professionals provide much support for developers to include client-side encryption to protect the confidentiality and integrity of information.

Examples of cloud storage services that provide client-side encryption are Tresorit, MEGA and SpiderOak. As of February 2016, neither Apple iCloud,Google Drive, or Dropbox provide client-side encryption.

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