Thread: A few questions about encryption and decryption

I'm working on an app that I might potentially want to market. I want to encrypt some of the information, and then have the user be able to "recall" that information, which then decrypts the string.

I want this to have a good amount of security, so it brings to mind a couple of questions:

1. What is a good encryption algorithm to use that I can also decrypt with? So, if I store, let's say, a piece of information that a user might need to retrieve, they can recall it unencrypted to use.

2. If I were to go about writing my own encryption/enciphering algorithm (with a private key), where would be a good place to store the key where it is not easily discovered? Additionally, here, I would want multiple keys, so that basically each item to be encrypted would have it's own private key.

I apologize if something like this has already been asked.