Simple, quick way to encrypt / decrypt a short string?

I'd like to encrypt and decrypt a query string.  Please, before you point me to <one of the many tutorials on how to make a secure, encrypted query string> ... All I want to do is encrypt it and decrypt it.  Security and making sure that it doesn't get tampered with isn't an issue in this case.  I did Google first and couldn't wrap my head around it because I don't know anything about DES or salt or Base64 or any other cryptic language :-)   I just would like to quickly understand how to take a string, encrypt it with any of the System.Security.Cryptography and then be able to decrypt it.

 

Thanks so much!

--Jack
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