Protecting Privacy in the Age of Government Surveillance: Exploring Cloudflare's ECH Technology
Introduction
Cloudflare, a renowned internet services provider, has introduced a new encryption technology called Encrypted Client Hello (ECH). While ECH enhances privacy by encrypting metadata in the TLS handshake, there are concerns surrounding its implementation. This article delves into the technical aspects of ECH and raises the question of whether its adoption could hinder government efforts to enforce laws and regulations.
Understanding the Difference: ECH vs. SNI
To comprehend ECH, it is important to compare it with Server Name Indication (SNI), an existing component of the TLS handshake. SNI involves sending the hostname in plaintext within the initial TLS record. In contrast, ECH hides the hostname within an encrypted section called ClientHelloInner, making it inaccessible to intermediaries.