加密和解密密码的最佳做法？ （C＃/。NET）

I need to store and encrypt a password in a (preferably text) file, that I later need to be able to decrypt. The password is for another service that I use, and needs to be sent there in clear text (over SSL). This is not something I can change. What are best practices in this area? How can achieve some degree of protection of the password from malicious users?I need to store and encrypt a password in a (pr