New XChaCha20-Poly130 may be missing from OTP if built with openssl 1.0.x

まず、Plug.Crypto バージョン 2 の要件ドキュメントと、OTP または OpenSSL の前提条件について説明している項目を見つけます。プロジェクトがこの依存関係をどのように文書化しているかを確認し、そのうえで、XChaCha20-Poly130 をサポートするには OTP を OpenSSL 1.1.x 以降でコンパイルする必要があることを説明する注記を追加します。レガシーシステムに関する制限が明確になれば完了です。

Probably this should be just a documentation update, but even with latest OTP 26, XChaCha20-Poly130 depends on the underlying openssl lib, which should be at least 1.1.x.

On systems with OTP26+ built with openssl 1.0.x the XChaCha20-Poly130 is not there and plug fails, even if the the otp/elixir stack is fully updated.

We have seen it on legacy CentOS7 and similar systems, which are still around.

I know that those are obsolete distros or setups, but OTP 26 can still be run on them and there's nothing that will alert that Plug.Crypto will fail, so probably just adding a note on the fact that version 2 of Plug.Crypto needs at least OTP compiled with openssl 1.1.x is more that enough.

Not related, just for the records, on some legacy distros there's a openssl11 compat package which may be used to build OTP with newer ssl (and will make Plug.Crypto 2 work) or even a patch for openssl 1.0.x by cloudflare which adds XChaCha20-Poly130 support (not tested).