Optimize AES and ChaCha20 usage with BoringSSL

BoringSSL is a Google fork of OpenSSL. It includes various interesting patches, including an implementation of the ChaCha20 cipher. In addition, BoringSSL allows you to group cipher suites of equal preference:

Equal preference cipher groups. This change implements equal-preference groups of cipher suites. This allows, for example, a server to prefer one of AES-GCM or ChaCha20 ciphers, but to allow the client to pick which one. When coupled with clients that will boost AES-GCM in their preferences when AES-NI is present, this allows us to use AES-GCM when the hardware exists and ChaCha20 otherwise.


In this article I show you how you can tweak your nginx configuration to take advantage of this feature.

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OpenSSL with ChaCha20-Poly1305 support

Update: Meanwhile you could also switch to the BoringSSL fork.

D. J. Bernstein’s ChaCha20-Poly1305 has not been merged into the OpenSSL master branch yet (ETA, anyone?). If you are curious to test it with nginx or any other application relying on the OpenSSL libraries with support for TLS 1.2, you can check it out via the 1.0.2-aead branch:

$ git clone https://github.com/openssl/openssl.git
$ cd openssl
$ git checkout 1.0.2-aead

Then follow the usual instruction from the INSTALL file on how to compile OpenSSL.