(VB.NET) RSA Signature with Certificate's Private Key from PFX

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Demonstrates how to use a certificate's private key from a PFX file to create an RSA signature.

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' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' Create an instance of a certificate store object, load a PFX file,
' locate the certificate we need, and use it for signing.
' (a PFX file may contain more than one certificate.)
Dim certStore As New Chilkat.CertStore

' The 1st argument is the filename, the 2nd arg is the 
' PFX file's password:
Dim success As Boolean = certStore.LoadPfxFile("chilkat.pfx","test")
If (success <> True) Then
    Debug.WriteLine(certStore.LastErrorText)
    Exit Sub
End If


Dim cert As Chilkat.Cert = certStore.FindCertBySubject("Chilkat Software, Inc.")
If (certStore.LastMethodSuccess = False) Then
    Debug.WriteLine(certStore.LastErrorText)
    Exit Sub
End If



Dim pkey As Chilkat.PrivateKey = cert.ExportPrivateKey()
If (cert.LastMethodSuccess = False) Then
    Debug.WriteLine(cert.LastErrorText)

    Exit Sub
End If



' Get the private key in XML format:
Dim pkeyXml As String = pkey.GetXml()

Dim rsa As New Chilkat.Rsa

' Import the private key into the RSA component:
success = rsa.ImportPrivateKey(pkeyXml)
If (success <> True) Then
    Debug.WriteLine(rsa.LastErrorText)

    Exit Sub
End If


' Encode the signature as a hex string
rsa.EncodingMode = "hex"

Dim strData As String = "This is the string to be signed."

' Sign the string using the sha-1 hash algorithm.
' Other valid choices are "sha-256", "md2" and "md5".
Dim hexSig As String = rsa.SignStringENC(strData,"sha-1")

Debug.WriteLine(hexSig)



Debug.WriteLine("Success!")