VB.NET

RSA Signature with Certificate's Private Key from PFX

See more RSA Examples

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

Dim success As Boolean = False

' 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:
success = certStore.LoadPfxFile("chilkat.pfx","test")
If (success = False) Then
    Debug.WriteLine(certStore.LastErrorText)
    Exit Sub
End If


' Find the certificate by the subject common name:
Dim jsonCN As New Chilkat.JsonObject
jsonCN.UpdateString("CN","cert common name")

Dim cert As New Chilkat.Cert
success = certStore.FindCert(jsonCN,cert)
If (success = False) Then
    Debug.WriteLine(certStore.LastErrorText)
    Exit Sub
End If


Dim privKey As New Chilkat.PrivateKey
success = cert.GetPrivateKey(privKey)
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Dim rsa As New Chilkat.Rsa

success = rsa.UsePrivateKey(privKey)
If (success = False) 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!")