What is Enhanced Privacy?
Sync gives you the option to enable zero-knowledge encryption on links!
With enhanced privacy enabled, linked files are only ever decrypted locally, by the web browser – making them zero-knowledge. This feature is fully supported by Chrome (files up to 25GB), Firefox and Safari (files up to 500MB in size), Internet Explorer 10+ (files up to 500MB in size) and Microsoft Edge (files up to 500MB in size). This feature may not be fully supported by Safari, and Safari mobile browsers.
While enabling zero-knowledge encryption on links is a great way to increase the privacy of a link, it also means that not everybody will be able to open the link. Recipients using Safari or mobile browsers may not be able to open the files contained within a link.
With enhanced privacy disabled, there are no file size limits, and virtually all web browsers (eg. Safari) are fully supported, however, when the link is viewed by the recipient the data may be streamed through a Sync mem-cache to help with local decryption. Of course, the link is still fully encrypted in transit, and the decrypted link data and encryption keys are never stored by Sync.
Sync provides both options to ensure that you can enable enhanced privacy on links when you need it, and enhanced compatibility when you need it. The choice is yours.