RSA Signature with Certificate's Private Key from PFX

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

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Dim success As Boolean

'  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:
success = certStore.LoadPfxFile("chilkat.pfx","test")
If (success <> true) Then
    MsgBox(certStore.LastErrorText)
    Exit Sub
End If


Dim cert As Chilkat.Cert
cert = certStore.FindCertBySubject("Chilkat Software, Inc.")
If (cert Is Nothing ) Then
    MsgBox(certStore.LastErrorText)
    Exit Sub
End If



Dim pkey As Chilkat.PrivateKey
pkey = cert.ExportPrivateKey()
If (pkey Is Nothing ) Then
    MsgBox(cert.LastErrorText)
    Exit Sub
End If



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


Dim rsa As New Chilkat.Rsa()

'  Any string argument automatically begins the 30-day trial.

success = rsa.UnlockComponent("30-day trial")
If (success <> true) Then
    MsgBox("RSA component unlock failed")
    Exit Sub
End If


'  Import the private key into the RSA component:
success = rsa.ImportPrivateKey(pkeyXml)
If (success <> true) Then
    MsgBox(rsa.LastErrorText)
    Exit Sub
End If


'  This example will sign a string, and receive the signature
'  in a hex-encoded string.  Therefore, set the encoding mode
'  to "hex":
rsa.EncodingMode = "hex"

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

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

TextBox1.Text = TextBox1.Text & hexSig & vbCrLf
TextBox1.Refresh()

MsgBox("Success!")