Here's the situation. I write an application that allows a user to connect to a third party cloud-based storage to upload/download data files from my application. That third party service requires a user to specify their user name and password for every session that my application attempts to connect to it. Unfortunately such user name and password must be provided in an open text form (although via a secure HTTPS protocol).

I will implement an option in my software (via a check box) to allow a user to chose to store their user name and password.

The question I have is how do you store this sensitive information on a local system?