How can I sign a document with a digital signature (PKCS12 Personal certificate) from an asp.net app

I have an asp.net website, from which I'll be uploading a document. I'll proceed to create a hash from the document so I can store it in a column for security reasons.

Bu开发者_运维知识库t I need to encrypt that "hash" using a certificate that lies in the Personal Certificate store of a user.

I'd like to do this from the browser, it doesn't matter if I end up with a solution where it can only be deployed in IE.

Our SecureBlackbox supports distributed signing and has client-side modules for browsers (Java applet, ActiveX control and Flash applet). It does exactly what you are looking for. PDF signing sample is included for C#.