April 5, 2008

PHP RC4 Encryption

One of the harder encryption problems comes when you need to encrypt something but need to also be able to decrypt it as well. I ran into such a problem recently in PHP. The regular simple methods such as sha1 or MD5 with a simple salt would not work because they are only one way, and to make matters worse the crypto modules I needed for a solution where not installed on the server.

Luckily I stumbled upon RC4Cript a simple php class that supports a simple RC4 encryption. Although RC4 is not exactly the safest encription Wikipedia, it was fine for simply securing the data I had, and I did not feel up to the task of coming up with a better solution. It took a while to get it to work because I was confused into thinking that I needed bin2hex() after encrypting it, however that is simply to give a more readable form, leave it as is when using the encrypted text in the decrypt function. Other than that, the source has an example that is pretty self explanatory.

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