AES_256_GCM for TLS.

Historically, TLS used AES ciphers based on a flawed CBC-mode-based construction. These ciphers are fragile and very difficult to implement securely. TLS 1.2 added better ciphers based on AES-GCM. We current support AES_128_GCM, but many servers order by key size above all else, placing the legacy AES_256_CBC above our preferred AES_128_GCM. To simplify server configuration and negotiate modern ciphers with more existing servers, we'll be adding AES_256_GCM as well.


Established standard

Status in Chromium


Enabled by default (launch bug) in:

  • Chrome for desktop release 51
  • Chrome for Android release 51
  • Opera release 38
  • Opera for Android release 38

Consensus & Standardization

  • No public signals
  • Shipped
  • Shipped
  • No signals


Last updated on 2017-06-14