(Visual FoxPro) Get Certificate Authority Information Access

Demonstrates how to get a certificate's Authority Information Access extension data (if it exists).

Note: This example requires Chilkat v9.5.0.76 or greater.

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

LOCAL loCert
LOCAL lnSuccess
LOCAL lcExtensionXmlStr
LOCAL loXml
LOCAL loSbOcsp
LOCAL loSbIssuer

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Cert')
loCert = CreateObject('Chilkat.Cert')

lnSuccess = loCert.LoadFromFile("qa_data/certs/test_haswdt.cer")
IF (lnSuccess <> 1) THEN
    ? loCert.LastErrorText
    RELEASE loCert
    CANCEL
ENDIF

* Get the Authority Information Access extension, which is at OID 1.3.6.1.5.5.7.1.1
lcExtensionXmlStr = loCert.GetExtensionAsXml("1.3.6.1.5.5.7.1.1")
IF (loCert.LastMethodSuccess = 0) THEN
    ? "Certificate does not have the AuthInfoAccess extension."
    RELEASE loCert
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Xml')
loXml = CreateObject('Chilkat.Xml')
loXml.LoadXml(lcExtensionXmlStr)

* See what we have..
? loXml.GetXml()

* We should get XML like this:

* <?xml version="1.0" encoding="utf-8" ?>
* <sequence>
*     <sequence>
*         <oid>1.3.6.1.5.5.7.48.2</oid>
*         <contextSpecific tag="6" constructed="0">aHR0cDovL2NydC5jb21vZG9jYS5jb20vQ09NT0RPUlNBQ2xpZW50QXV0aGVudGljYXRpb25hbmRTZWN1
* cmVFbWFpbENBLmNydA==</contextSpecific>
*     </sequence>
*     <sequence>
*         <oid>1.3.6.1.5.5.7.48.1</oid>
*         <contextSpecific tag="6" constructed="0">aHR0cDovL29jc3AuY29tb2RvY2EuY29t</contextSpecific>
*     </sequence>
* </sequence>

* Typically, a certificate AIA(Authority Information access) contains 2 parts:
* 
*     On-line Certificate Status Protocol (1.3.6.1.5.5.7.48.1)
*     Certification Authority Issuer (1.3.6.1.5.5.7.48.2)
* 
* The base64 content for each OID (in this case) is just a string.  
* The data can be accessed and decoded like this:

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbOcsp = CreateObject('Chilkat.StringBuilder')
lnSuccess = loXml.GetChildContentSb("/C/oid,1.3.6.1.5.5.7.48.1|++",loSbOcsp)
IF (lnSuccess = 1) THEN
    loSbOcsp.Decode("base64","utf-8")
    ? "1.3.6.1.5.5.7.48.1:  " + loSbOcsp.GetAsString()
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.StringBuilder')
loSbIssuer = CreateObject('Chilkat.StringBuilder')
lnSuccess = loXml.GetChildContentSb("/C/oid,1.3.6.1.5.5.7.48.2|++",loSbIssuer)
IF (lnSuccess = 1) THEN
    loSbIssuer.Decode("base64","utf-8")
    ? "1.3.6.1.5.5.7.48.2:  " + loSbIssuer.GetAsString()
ENDIF

* The output looks like this:

* 1.3.6.1.5.5.7.48.1:  http://ocsp.comodoca.com
* 1.3.6.1.5.5.7.48.2:  http://crt.comodoca.com/COMODORSAClientAuthenticationandSecureEmailCA.crt

* -------------------------------------------------------------------------------
* Note: The Chilkat path passed to GetChildContentSb is composed of two commands:
* The first command is "/C/oid,1.3.6.1.5.5.7.48.1".   It says "traverse the XML tree from the caller
* node and stop at the 1st node having tag = "oid" and content = "1.3.6.1.5.5.7.48.1".
* The "|" char separates the 1st command from the 2nd.
* The 2nd command is "++" and says "move to the next sibling".

RELEASE loCert
RELEASE loXml
RELEASE loSbOcsp
RELEASE loSbIssuer