Hi folks, I want to encrypt a short (10-100 chars) string into a new string of the same length, using a key of, say, 8 chars, then decrypt it using the same key. The original string and key contain only hexadecimal characters ("0".."9", "A".."F"). So should the encrypted string too. I don't need high security, just a plain hacker- and robot- proof barrier. I don't want to use a package or module, I prefer writing it myself (with your help if possible) ) The encryption and decryption should probably fit inside 40 lines of code. Target language : Perl and/or PHP. Pseudo-code welcome if readable ! Any ideas ? Thanks in advance.