(Visual Basic 6.0) Load Certificate from Smart Card by Key Usage

See more Certificates Examples

You may have a smartcard or USB token that contains only 2 certificates, one for signing, and one for authentication, and you wish to load the certificate for signing. This example demonstrates how to load the 1st certificate found on a smartcard that matches the intended key usage.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

Dim cert As New ChilkatCert

' If you know the smart card PIN, set it prior to loading from the smartcard/USB token.
cert.SmartCardPin = "12345678"

' To load a certificate matching an intended key usage, specify the type of usage as shown below.
' 
' The possible key usage keywords are:
' 
' digitalsignature
' Use when the public key is used with a digital signature mechanism to support security services other than non-repudiation, certificate signing, or CRL signing. 
' A digital signature is often used for entity authentication and data origin authentication with integrity.

' nonrepudiation
' When a digital certificate's key usage includes "nonrepudiation," it implies that the certificate and its associated private key can be used to 
' create digital signatures that provide proof of the origin and integrity of the signed data, and the signer cannot later deny having signed the data.

' Other less common usages:

' certificatesigning
' keyencipherment
' dataencipherment
' crlsigning
' secureemail
' serverauthentication
' clientauthentication
' codesigning
' timestamping

Dim success As Long
success = cert.LoadFromSmartcard("keyusage=nonrepudiation")
If (success = 0) Then
    Debug.Print cert.LastErrorText
    Debug.Print "Certificate not loaded."
    Exit Sub
End If

Debug.Print "Found: " & cert.SubjectDN & " serial=" & cert.SerialNumber