B4X

PKCS11 Find Certificate with Key Usage on Smart Card or USB Token

See more PKCS11 Examples

Demonstrates how to find and return the 1st certificate on a smart card or USB token with a desired intended key usage.

Note: This example requires Chilkat v9.5.0.91 or later.

B4X

Dim success As Boolean = False

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

'  Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

Dim pkcs11 As ChilkatPkcs11
pkcs11.Initialize

pkcs11.SharedLibPath = "aetpkss1.dll"

success = pkcs11.InitializeLibrary
If success = False Then
    Log(pkcs11.LastErrorText)
    Return
End If


'  Pass -1 for the slotID to open a session on the first non-empty slot.
Dim slotID As Int = -1

'  Open a session.
Dim readWrite As Boolean = True
success = pkcs11.OpenSession(slotID, readWrite)
If success = False Then
    Log(pkcs11.LastErrorText)
    Return
End If


'  Make it an authenticated session by calling Login.
'  
'  If we don't authenticate, then we won't be able to see the private keys, and thus
'  we won't know which certificates have an associated private key stored on the smart card.

'  The smart card PIN is passed to the Login method.
'  userType 1 indicates a "Normal User".
Dim userType As Int = 1
Dim pin As String = "0000"
success = pkcs11.Login(userType, pin)
If success = False Then
    Log(pkcs11.LastErrorText)
    success = pkcs11.CloseSession
    Return
End If


'  --------------------------------------------------------------------------

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

'  Find a certificate with an intended key usage.
'  Possible key usages to find are:
'  
'  DigitalSignature
'  NonRepudiation
'  KeyEncipherment
'  DataEncipherment
'  CertificateSigning
'  CrlSigning
'  
'  To find a cert having any one of several usages, pass a comma-separated list of usages:
success = pkcs11.FindCert("keyUsage", "NonRepudiation,DigitalSignature", cert)
If success = True Then
    Log("Cert with private key: " & cert.SubjectCN)
Else
    Log("No certificates having the intended key usage were found.")
End If


'  --------------------------------------------------------------------------

'  Revert to an unauthenticated session by calling Logout.
success = pkcs11.Logout
If success = False Then
    Log(pkcs11.LastErrorText)
    success = pkcs11.CloseSession
    Return
End If


'  When finished, close the session.
'  It is important to close the session (memory leaks will occur if the session is not properly closed).
success = pkcs11.CloseSession
If success = False Then
    Log(pkcs11.LastErrorText)
    Return
End If


Log("Success.")