Ruby - unsupported cipher algorithm (AES-256-GCM)
What works for me is
OpenSSL::Cipher.new('aes-128-gcm')
I am not sure why you get an error with your approach.
Edit:
It might be a upper/lower case issue. This might be an actual bug.
The following works:
OpenSSL::Cipher::AES.new(128, :CBC)
because we find "AES-128-CBC"
(all upper case) in OpenSSL::Cipher::AES.ciphers
. AES.new
seems to search its ciphers with upper case characters.
Thus, the following does not work:
OpenSSL::Cipher::AES.new(128, :GCM)
because it is "aes-128-gcm"
in the ciphers list.