(Visual FoxPro) Examine KeyInfo Certificate in XML Signature

This example loads signed XML and gets the signing certificate, assuming the certificate is contained in X509Certificate within the KeyInfo.

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

LOCAL loDsig
LOCAL loSbXml
LOCAL lnSuccess
LOCAL loXmlKeyInfo
LOCAL lcCertBase64
LOCAL loCert

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.XmlDSig')
loDsig = CreateObject('Chilkat.XmlDSig')
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbXml = CreateObject('Chilkat.StringBuilder')

lnSuccess = loSbXml.LoadFile("c:/aaworkarea/elias/3/face_f09006808443a699d1b.xml","utf-8")
IF (lnSuccess <> 1) THEN
    ? "Failed to load XML file."
    RELEASE loDsig
    RELEASE loSbXml
    CANCEL
ENDIF

lnSuccess = loDsig.LoadSignatureSb(loSbXml)
IF (lnSuccess <> 1) THEN
    ? loDsig.LastErrorText
    RELEASE loDsig
    RELEASE loSbXml
    CANCEL
ENDIF

* Get the KeyInfo XML.
loXmlKeyInfo = loDsig.GetKeyInfo()
IF (loDsig.LastMethodSuccess <> 1) THEN
    ? loDsig.LastErrorText
    RELEASE loDsig
    RELEASE loSbXml
    CANCEL
ENDIF

? loXmlKeyInfo.GetXml()
? "----"

* Assuming the X509Certificate is in the KeyInfo, it will look like this:

*   <ds:KeyInfo Id="...">
*     <ds:KeyValue>
*     ...  
*     <ds:X509Data>
*       <ds:X509Certificate>MIIHAz...</ds:X509Certificate>
*     </ds:X509Data>
*   </ds:KeyInfo>
lcCertBase64 = loXmlKeyInfo.GetChildContent("*:X509Data|*:X509Certificate")
IF (loXmlKeyInfo.LastMethodSuccess <> 1) THEN
    ? "No X509Certificate found in the KeyInfo."
    RELEASE loDsig
    RELEASE loSbXml
    CANCEL
ENDIF

* Load a certificate object w/ the base64.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadFromBase64(lcCertBase64)
IF (lnSuccess <> 1) THEN
    ? loCert.LastErrorText
    RELEASE loDsig
    RELEASE loSbXml
    RELEASE loCert
    CANCEL
ENDIF

* Examine the cert..
? "SubjectDN: " + loCert.SubjectDN
? "IssuerDN: " + loCert.IssuerDN
? "SerialNumber as Decimal: " + loCert.SerialDecimal

RELEASE loXmlKeyInfo

RELEASE loDsig
RELEASE loSbXml
RELEASE loCert