Updated: 1/14/24
Note: Also known as and referred to as "Client-Side Encryption".
End-to-end encryption is the term used for a type of encryption where your data is encrypted at every stage of its journey from one device to another. The ends in “end-to-end” refer to the beginning and final destination of your data’s journey.
For example, if you’re sending an email, the beginning point is your device and the destination is your recipient’s device. The company, corporation or service provider DOES NOT hold your "Private Encryption Keys".
This makes end-to-end encryption a secure communication method that prevents all third parties from accessing the content of your messages, including while they are transferred from one device to another or “at rest” on a server.
When you use E2EE to send an email to someone, no one else can see the content of your message — not your network administrator, not your internet service provider (ISP), not hackers, not the government, and not even the company that handles the delivery of your email (for example, Proton Mail).