B4X

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. B4X

Dim success As Boolean = False

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

Dim cert As ChilkatCert
cert.Initialize("cert")

'  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

success = cert.LoadFromSmartcard("keyusage=nonrepudiation")
If success = False Then
    Log(cert.LastErrorText)
    Log("Certificate not loaded.")
    Return
End If


Log("Found: " & cert.SubjectDN & " serial=" & cert.SerialNumber)