I want to pass a variable containing a string to a hidden field in the output html page (assuming I don't want to store the variable elsewhere like writing it to a file or saving it in a cookie). I'm wondering whether there is a perl built in function to encrypt the string so that it's not so easily readable. The reason I need to do this is because the string contains the answer to a puzzle so I want to prevent people from looking at the source code of the html page and discover the answer easily. Presumably I will need a way to decrypt the encrypted string. I don't intend the encryption to be fool-proof - as long as the encrypted string is harder to read. How do I do that?