PHP3 Cryption is a relatively insecure encryption function that shouldn't be used for anything of great importance. Though the encryption is good, it's not going to hold up to the rigors of sophisticated cracking procedures.
That said, try it out... it's a great way to encrypt and decrypt strings. I use it to encrypt items in hidden form fields, url strings and cookies. This way, a person can't easily change values you are passing along. It's not bulletproof, but it helps. If you need high security, please look elsewhere. I honestly don't know how secure this class is, but chances are it could be hacked by an experienced computer programmer.
Unlike many crypt functions, this goes both ways. Based on a password, you can encrypt or decrypt. You can also decrypt or encrypt numerous time, through looping or other methods. The alphabet of characters is also changeable. All these things allow you to modify and solidify the encryption. Not only does a hacker need your password, but s/he must also know how many times you looped, re-encrypting each time, and what alphabet you used. This adds up to be a pain in the butt for your average web surfer and they aren't likely to take the time to hack it unless you are trying to protect government secrets (please don't do this with this class!).The best part about this? You can decrypt or encrypt with a piece of paper and a pencil. It takes quite a bit longer, but you don't need to be near a computer to use it, and if you ever lose the code, if you remember the technique you can decrypt it. It's NOT a simple substitution function, it's much better than that.
To test out the encryption, fill out the form below with any string and any password.