Required USB token based digital signature implementation for document signing on client side

Required USB token based digital signature implementation for document signing on client side, Steps to fololow 1. initially user will attach/register his USB token in web based asp.net C# application. 2. At the time of document signing the application will ask user to place the registered USB token in the system. 3. The user will place the USB token in the system an d select the correct signature from the displayed screen and insert his password. 4. After this process the documents will be digitally signed.