(Excel) 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.

Download Excel Class Modules Chilkat Excel Class Modules

' 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 Chilkat.CertStore
Set certStore = Chilkat.NewCertStore

' 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
    Debug.Print certStore.LastErrorText
    Exit Sub
End If


Set cert = certStore.FindCertBySubject("Chilkat Software, Inc.")
If (certStore.LastMethodSuccess = False) Then
    Debug.Print certStore.LastErrorText
    Exit Sub
End If


Set pkey = cert.ExportPrivateKey()
If (cert.LastMethodSuccess = False) Then
    Debug.Print cert.LastErrorText

    Exit Sub
End If

' Get the private key in XML format:

pkeyXml = pkey.GetXml()

Dim rsa As Chilkat.Rsa
Set rsa = Chilkat.NewRsa

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

    Exit Sub
End If

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


strData = "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".

hexSig = rsa.SignStringENC(strData,"sha-1")

Debug.Print hexSig

Debug.Print "Success!"