I need a simple encryption/decryption routine that will encrypt strings to fixed-length alpha-numeric strings using a password. Of course, I don't want to use a simple Select Case character replacement.

The encrypted string can be longer than the input string as long as it's always the same number of characters. For example, if you encrypt any 10 character string, it may come out to say, 20 characters. But no matter what the input string is, as long as it's 10 characters, the output would always be 20 (always the same length). In case I'm not being clear, a 10 character input string could encrypt to even 35 characters, as long as it was the same length every time.

Also, it doesn't need to use high encryption, but it does need to look pretty random.

For example, the input string with some repeating characters like this: "This is a testttttttttt" might come out to "aY3K0rkQnv4NVrziR1oNFcx" but not something like "aY3K0rkQnv4NVrzieeeeeeeeee". I need to have the encrypted string to look random, even if there are some repeating characters.

It would need to be 2 functions that may look like this:
Function Encrypt(sPassword as String, sInput as String) as String
and
Function Decrypt(sPassword as String, sInput as String) as String

If you have a sample EXE already done to send, all the better.

Visual Basic 6