Canonical XML with SHA1

[VAISH]

Hi
I am using C# (.NET) to do the following

I am trying to canonicalize the xml and signing the xml using sha1. Please read the scenario below

I have form with few fields, when I click save it will point to DLL file, then DLL file load the xml from the form and do the signing and giving me the value somthing like FGThHy509-sfjGHTmn+jgkjgk = and save output as an XML file. So far is fine. The calculated value will be saved between the <Dvalue type="sign">FGT hHy509-sfjGHTmn+jgkjgk =</Dvalue>

The code I am using to save the calculated value is

__strFileConten t = _strFileContent .Replace("<DVal ue Type=\"sign\"></DValue>","<DVal ue Type=\"sign\">" + _strKey +"</DigestValue>");

The above code only work if the same element (<Dvalue type="sign">) is present in the form.

Note: Sha1 -FGThHy509-sfjGHTmn+jgkjgk =----This value will change for a small change in the form.

My question:-

Question 1. How do I remove the element <DValue Type=\"sign\"></DValue> before the xml from form loaded to the DLL file or memory, then I can use the above said code

_strFileContent = _strFileContent .Replace("<DVal ue Type=\"sign\"></DValue>","<DVal ue Type=\"sign\">" + _strKey +"</DigestValue>");

OR OR OR OR

Question 2. If I remove the element <DValue Type=\"sign\"></DValue> permanantly from the form ,then WHAT CODE I USE to add the calculated (SHA1- FGThHy509-sfjGHTmn+jgkjgk =) with the element <DValue Type=\"sign\"></DValue> to the output xml file.


The reason I am trying to do the above is , SHA1 calculating digest value including this element <DValue Type=\"sign\"></DValue> . BUT I AM TRING TO CALCULATE SHA1 EXCLUDE THE ABOVE ELEMENT and at the same time it has to present in the form in order to use this code (__strFileConte nt.Replace("<DV alue Type=\"sign\"></DValue>","<DVal ue Type=\"sign\">" + _strKey +"</DigestValue>");


Please give your ideas. I am new and try to solve this with the code I found in the internet.But THERE MUST BE SIMPLE OPTION TO ACHIVE THE ABOVE.