Hi,

I'm new to cryptology and digital signature. I have an Electronic Content Management application and I'd like to give the possibility to the user to sign his documents (digital signature). I have found some algorithms which generate keys or validate but I don't know how to work really. My documents maybe pdf, docs, xls, txt,jpeg... How can I make in order to sign these formats? Is the API XMLdsig useful for me?
I'm a little lost and i really appreciate some help in order to know what can I do (have i to use external equipment such as card driver?) and how.
Thanks in advance for all answers
Best Regards
Alfred