What does client-side encryption refer to?

Client-side encryption refers to the process of encrypting data on the client side before it is sent to a storage service like Amazon S3. This means that the data is transformed into an unreadable format using cryptographic algorithms on the user's device, ensuring that only authorized parties with the appropriate decryption keys can access the original data.

By encrypting data prior to transmission, client-side encryption provides an additional layer of security. Only the client holds the key necessary to decrypt the data, and even the storage provider (like Amazon S3) cannot access the plaintext data without that key. This approach is particularly beneficial for meeting compliance and regulatory requirements, as it allows users to maintain control over their sensitive information, ensuring that it remains confidential even when stored in the cloud.

The other choices reflect different aspects of data security: data encryption in transit refers to securing data as it moves between the client and server, server-side data encryption involves encrypting data after it arrives at the server, and end-to-end encryption encompasses a broader strategy where data is kept encrypted from the originating client all the way to the final recipient, potentially involving multiple servers. While relevant, they do not accurately define client-side encryption specifically.