Overview

  • Android 17 introduces Encrypted Client Hello, which enhances privacy by concealing domain names during connection setup.
  • This is the first major implementation of this feature on a mobile OS, developed by Google’s Jigsaw team and partners.
  • The feature is effective only for websites and apps that have adopted Encrypted Client Hello; other sites will still expose their domain names.

The latest update in Android 17 brings a significant privacy upgrade for users browsing online. This rollout, announced on Wednesday, activates the Encrypted Client Hello (ECH) feature, which protects the destination of web requests from being visible to networks.

While HTTPS encrypts the content of web pages, the initial connection handshake still reveals the website name in clear text through the Server Name Indication (SNI) field. This visibility allows intermediaries to log the requested site.

With ECH, the site name is encrypted using a key from the destination server, meaning networks will only see a random identifier instead of the actual domain name. This works in conjunction with private DNS, which already secures the translation of domain names to IP addresses.

It’s crucial to note that ECH will only protect traffic to supported websites and applications. Google encourages developers to upgrade to OkHttp 5.5.0 to enable this feature, as sites not using ECH will still reveal their domain names.

Although the actual site name remains hidden, networks can still identify the destination server's IP address and the volume of data being transferred, allowing for some level of activity inference.

This privacy enhancement arrives amid legal scrutiny concerning Android’s privacy features. Activist Samuel Tunick has become the first American charged under federal law for allegedly using a duress password in GrapheneOS, a secure Android variant that wipes the device upon entering the password. Tunick argues that the government should not control personal data.

In addition to ECH, Android 17 has also enabled Certificate Transparency by default and requires applications to seek permission before scanning local networks.