Jeff659
Dude,
Form what you say, you want to store a file which contans a list of passwords for <other> systems.
So, essentially, the fact that it's "Passwords" you are storing is a red herring. In effect, you have a file containing data you want to secure.
you are correct in that tyring to write your own algorithm is a bad idea. writing an encryption algorithm is easy. writing a strong encryption algorithm is hard. The problem is that you have no way of knowing which you have unless you open it up to the cyrptography community for them to test. Stick with one of the "standard" algorithms (which HAVE been tested by the comminuty...)
Do you intend sending the file to others so they can open it In which case, you can use an asymmetric algorithm (with public & private keys - use the recipient's public key to encrypt, so only they can decrypt with their private key). Or will it stay on one machine in which case you can use symmetric algorithm's (the same key is used to encrypt and de-crypt).
Of course, if you are going to send the file to someone, you can still use the more secure symmetric methods, but you will need a secure way of giving them the key (the normal method is to exchange public keys, use private keys to encrypt and send the symmetric key, and then use the symmetric key for the data.)
So which sould you choose Whichever best fits your needs.
if you go asymmetric RSA, or DH (Diffie-Hellman) could be used.
If you go symmetric, 3des (aka TrippleDES),or AES (aka Rijndael) are both good.
There are others, too.....
But if you ask for a definative opinion, then you'll get as many different answers as you care to read..... On the whole, the more bits in the key the better....
Hope this helps
Jeff