Visual FoxPro

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.

Visual FoxPro

LOCAL lnSuccess
LOCAL loPkcs11
LOCAL lnSlotID
LOCAL lnReadWrite
LOCAL lnUserType
LOCAL lcPin
LOCAL loCert

lnSuccess = 0

*  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.

loPkcs11 = CreateObject('Chilkat.Pkcs11')

loPkcs11.SharedLibPath = "aetpkss1.dll"

lnSuccess = loPkcs11.Initialize()
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    RELEASE loPkcs11
    CANCEL
ENDIF

*  Pass -1 for the slotID to open a session on the first non-empty slot.
lnSlotID = -1

*  Open a session.
lnReadWrite = 1
lnSuccess = loPkcs11.OpenSession(lnSlotID,lnReadWrite)
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    RELEASE loPkcs11
    CANCEL
ENDIF

*  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".
lnUserType = 1
lcPin = "0000"
lnSuccess = loPkcs11.Login(lnUserType,lcPin)
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    lnSuccess = loPkcs11.CloseSession()
    RELEASE loPkcs11
    CANCEL
ENDIF

*  --------------------------------------------------------------------------

loCert = CreateObject('Chilkat.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:
lnSuccess = loPkcs11.FindCert("keyUsage","NonRepudiation,DigitalSignature",loCert)
IF (lnSuccess = 1) THEN
    ? "Cert with private key: " + loCert.SubjectCN
ELSE
    ? "No certificates having the intended key usage were found."
ENDIF

*  --------------------------------------------------------------------------

*  Revert to an unauthenticated session by calling Logout.
lnSuccess = loPkcs11.Logout()
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    lnSuccess = loPkcs11.CloseSession()
    RELEASE loPkcs11
    RELEASE loCert
    CANCEL
ENDIF

*  When finished, close the session.
*  It is important to close the session (memory leaks will occur if the session is not properly closed).
lnSuccess = loPkcs11.CloseSession()
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    RELEASE loPkcs11
    RELEASE loCert
    CANCEL
ENDIF

? "Success."

RELEASE loPkcs11
RELEASE loCert