Using InstallAware to Verify a Signed XML License

[greenstone]

What is the best way for an InstallAware installer to verify a license key-- which is in the form of a signed xml document?

The scenario is as follows:
1.) User runs the installer which goes to a "license entry" page
2.) User pastes a license key (in the form of a signed xml document) into a field
3.) Installer verifys the license by
a.) xsd validating the xml
b.) signature validating the xml


********************
Following is the VB.NET code we use in the code to signature validate the XML:


' Verify the signature of an XML file against an asymetric algorithm and return the result.
Private Shared Function VerifyXmlDocument(ByVal xmlDocument1 As System.Xml.XmlDocument, _
ByVal key As System.Security.Cryptography.AsymmetricAlgorithm) As Boolean

' Create a new SignedXml object and pass it the XML document class.
Dim signedXml As New System.Security.Cryptography.Xml.SignedXml(xmlDocument1)

' Find the "Signature" node and create a new XmlNodeList object.
Dim nodeList As System.Xml.XmlNodeList = xmlDocument1.GetElementsByTagName(SignatureElement)

' Load the signature node.
signedXml.LoadXml(CType(nodeList(0), System.Xml.XmlElement))

' Check the signature and return the result.
Return signedXml.CheckSignature(key)

End Function

[Alex_Ronquillo]

You can create a DLL from your VB.NET code. After that you can call the functions in your DLL from inside IA with the Call DLL Function plug-in. That shoud do it

[greenstone]

Hi Alex,

Thanks for the reply.

My current understanding is that I can only call a Win32 DLL from Installaware. Could you explain how I can call a .NET dll?

(per a prior email from Candace at InstallAware)
You cannot call COM objects from InstallAware. You can call Win32 DLLs (or other DLLs using the stdcall calling convention).

Thanks for the clarification!

[greenstone]

Hi Alex,

Thanks for the reply.

My current understanding is that I can only call a Win32 DLL from Installaware. Could you explain how I can call a .NET dll?

(per a prior email from Candace at InstallAware)
You cannot call COM objects from InstallAware. You can call Win32 DLLs (or other DLLs using the stdcall calling convention).

Thanks for the clarification!

[Gizm0]

Alex made a mistake. You cannot call non-native (Win32) dlls from InstallAware. The best to thing to do is create a small .exe file and run it with "Run Program" to validate the xml file and catch it's exit code (for example 2 for success, -1 for failure).

[greenstone]

Thanks for the clarification and approach.

[Alex_Ronquillo]

Sorry, that is right. I misunderstood it for a moment. Gizmo is right. Sorry for the wrong advice

[greenstone]

No problem!