Are the security encryption classes in .NET Useable on mono run times? (In particular monogame implementations that use mono run time on Mac etc.)
I am mostly interested in if I can use the [AES] (https://msdn.microsoft.com/en-us/library/system.security.cryptography.aes(v=vs.110).aspx) class because I have used it before.
Would I be able to encrypt strings (such as config data) to obfuscate it and then save that as a file and later decrypt it back in the program.
Yes ... you can use these classes on mono-backed platforms such as MacOS :)
https://developer.xamarin.com/api/type/System.Security.Cryptography.Aes/
edit: @zaph makes an excellent point in the comments ... there are libraries, such as PCLCrypto that use the native libraries on each platform for this very reason :)