User lower case cipher names for maximum compatibility

[bdewater]

We ran into some Linux-based systems not accepting the upper case variant, see rubocop/rubocop#8262

[tas50]

@bdewater Any idea which versions of openssl are impacted by the uppercase ciphers?

[bdewater]

Seems Ubuntu 16.04 supports some uppercase ciphers (e.g. AES-128-CBC) and 20.04 none. We didn't find anything in the changelog between OpenSSL 1.0.2 and 1.1.1 about this but also we just fixed it and moved on.

[rhenium]

For more context, the AES-GCM ciphers have an associated "short name" id-aesNNN-GCM and a "long name" aes-NNN-gcm while many other AES ciphers have a short name AES-NNN-<mode> (in upper case) and a long name aes-NNN-<mode> (in lower case).

EVP_get_cipherbyname(), which OpenSSL::Cipher.new calls, takes both short names and long names. It was doing case-sensitive string comparison in OpenSSL versions prior to 1.1.0j or 1.1.1, hence OpenSSL::Cipher.new("AES-128-GCM") did not work.