I'm going to be converting a string of characters into a barcode format. These characters will be your standard ASCII characters, notably A-Z, 0-9 and perhaps a few symbols if possible.
The problem is, I want to encrypt this string, so that even if someone has a barcode scanner, what they scan will be gibberish. But when encrypting the string, I don't want the length of the string to increase too much because the barcode can only support a maximum number of characters. Add to this problem, I think my barcode format (PDF417) can only support ASCII and not unicode (I think a unicode character takes up a lot of space).
I'm NOT saying that the encrypted version should be the exact same length as the decrypted version.
I'm using Delphi, and need a simple encryption and decryption process please.