and in the release note of application crypto 4.0, this feature is enabled
"Crypto chacha20-poly1305 as in RFC 7539 enabled for OpenSSL >= 1.1."
so I think it’s a libressl compatibility issue, hope the someone can fix it
Chacha was disabled for LIBRESSL to get LIBRESSL to work at all, so I guess it might be a compatibility issue between LIBRESSL and OPENSSL.
Contributions in this area are welcome.
As as side note. We discovered interop problems with the chacha20-poly1305 cipher and hence we have removed it from the default cipher list in our ssl application until we are able to fix it. It is a problem with how crypto calls OpenSSLs crypto lib with subtitles in how padding is handled.
It is still possible to use the cipher by adding it to the the ciphers list see ssl:cipher_suites/2, ssl:filter_cipher_suites/2, ssl:prepend_cipher_suites/2 ssl:append_cipher_suites/2. But probably this will only work for erlang client
vs erlang server as they will then do the same thing.