Here is some code from a project I have been working on and then shelved. A C# (mono) project creates a RSA public/private key pair, then gives the public side to a MySQL database. The private side is saved to the hard drive for later. Then PHP dynamically adds the currently active key public portion into javascript, which encrypts the users input, and saves it to MySQL. Then the C# application can get the keys it has saved in a good place, and decrypt the data in the database. Benefits of this include the web data is secured from the client to the server, and even if somehow someone steals your database off your webserver, they dont have the encryption keys to take it away. This system also has a way to deactivate a old key and move to a new one, if more code was put into it someone could revoke a old key and migrate all the data using it to a new key, but that wasn’t implemented. I thought this would be a cool project and I learned a lot about RSA public private keys, a lot of languages handle the keys differently; some take it in hex, some do it differently, some call the parts one thing, some call them other names. The javascript portion is based mostly off this library (link). JQuery is used for ease.
Feel free to give feed back or use this, open source fun.
BuildingTents 