VBScript Requires Chilkat v11.0.0+
Validate Certificate using OCSP Protocol

Demonstrates how to validate a certificate (check the revoked status) using the OCSP protocol.
Chilkat VBScript Downloads

VBScript
Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

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

'  This example will check the revoked status of a certificate loaded from a file.
set cert = CreateObject("Chilkat.Cert")
success = cert.LoadFromFile("qa_data/certs/google.crt")
If (success = 0) Then
    outFile.WriteLine(cert.LastErrorText)
    WScript.Quit
End If

'  Get the cert's OCSP URL.
ocspUrl = cert.OcspUrl

'  Build the JSON that will be the OCSP request.

'  Possible hash algorithms are sha1, sha256, sha384, sha512.  
hashAlg = "sha256"
set prng = CreateObject("Chilkat.Prng")
set json = CreateObject("Chilkat.JsonObject")
json.EmitCompact = 0
'  Read more about OCSP nonce lengths
success = json.UpdateString("extensions.ocspNonce",prng.GenRandom(16,"base64"))
json.I = 0
success = json.UpdateString("request[i].cert.hashAlg",hashAlg)
success = json.UpdateString("request[i].cert.issuerNameHash",cert.HashOf("IssuerDN",hashAlg,"base64"))
success = json.UpdateString("request[i].cert.issuerKeyHash",cert.HashOf("IssuerPublicKey",hashAlg,"base64"))
success = json.UpdateString("request[i].cert.serialNumber",cert.SerialNumber)

outFile.WriteLine(json.Emit())

'  Our OCSP request looks something like this:
'  {
'    "extensions": {
'      "ocspNonce": "qZDfbpO+nUxRzz6c/SPjE5QCAsPfpkQlRDxTnGl0gnxt7iXO"
'    },
'    "request": [
'      {
'        "cert": {
'          "hashAlg": "sha1",
'          "issuerNameHash": "9u2wY2IygZo19o11oJ0CShGqbK0=",
'          "issuerKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
'          "serialNumber": "6175535D87BF94B6"
'        }
'      }
'    ]
'  }

set ocspRequest = CreateObject("Chilkat.BinData")
set http = CreateObject("Chilkat.Http")

'  Convert our JSON to a binary (ASN.1) OCSP request
success = http.CreateOcspRequest(json,ocspRequest)
If (success = 0) Then
    outFile.WriteLine(http.LastErrorText)
    WScript.Quit
End If

'  Send the OCSP request to the OCSP server
set resp = CreateObject("Chilkat.HttpResponse")
success = http.HttpBd("POST",ocspUrl,ocspRequest,"application/ocsp-request",resp)
If (success = 0) Then
    outFile.WriteLine(http.LastErrorText)
    WScript.Quit
End If

'  Get the binary (ASN.1) OCSP reply
set ocspReply = CreateObject("Chilkat.BinData")
success = resp.GetBodyBd(ocspReply)

'  Convert the binary reply to JSON.
'  Also returns the overall OCSP response status.
set jsonReply = CreateObject("Chilkat.JsonObject")
ocspStatus = http.ParseOcspReply(ocspReply,jsonReply)

'  The ocspStatus can have one of these values:
'  -1:  The ARG1 does not contain a valid OCSP reply.
'  0:  Successful - Response has valid confirmations..
'  1: Malformed request - Illegal confirmation request.
'  2: Internal error - Internal error in issuer.
'  3: Try later -  Try again later.
'  4: Not used - This value is never returned.
'  5: Sig required - Must sign the request.
'  6: Unauthorized - Request unauthorized.

If (ocspStatus < 0) Then
    outFile.WriteLine("Invalid OCSP reply.")
    WScript.Quit
End If

outFile.WriteLine("Overall OCSP Response Status: " & ocspStatus)

'  Let's examine the OCSP response (in JSON).
jsonReply.EmitCompact = 0
outFile.WriteLine(jsonReply.Emit())

'  The JSON reply looks like this:
'  (Use the online tool at https://tools.chilkat.io/jsonParse.cshtml
'  to generate JSON parsing code.)

'  {
'    "responseStatus": 0,
'    "responseTypeOid": "1.3.6.1.5.5.7.48.1.1",
'    "responseTypeName": "ocspBasic",
'    "response": {
'      "responderIdChoice": "KeyHash",
'      "responderKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
'      "dateTime": "20180803193937Z",
'      "cert": [
'        {
'          "hashOid": "1.3.14.3.2.26",
'          "hashAlg": "SHA-1",
'          "issuerNameHash": "9u2wY2IygZo19o11oJ0CShGqbK0=",
'          "issuerKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
'          "serialNumber": "6175535D87BF94B6",
'          "status": 0,
'          "thisUpdate": "20180803193937Z",
'          "nextUpdate": "20180810193937Z"
'        }
'      ]
'    }
'  }
'  

'  The certificate status:
certStatus = -1
If (jsonReply.HasMember("response.cert[0].status") = 1) Then
    certStatus = jsonReply.IntOf("response.cert[0].status")
End If

'  Possible certStatus values are:
'  -1: No status returned.
'  0: Good
'  1: Revoked
'  2: Unknown.
outFile.WriteLine("Certificate Status: " & certStatus)

outFile.Close