Classic ASP 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 Classic ASP Downloads

Classic ASP
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<%
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 = Server.CreateObject("Chilkat.Cert")
success = cert.LoadFromFile("qa_data/certs/google.crt")
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( cert.LastErrorText) & "</pre>"
    Response.End
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 = Server.CreateObject("Chilkat.Prng")
set json = Server.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)

Response.Write "<pre>" & Server.HTMLEncode( json.Emit()) & "</pre>"

'  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 = Server.CreateObject("Chilkat.BinData")
set http = Server.CreateObject("Chilkat.Http")

'  Convert our JSON to a binary (ASN.1) OCSP request
success = http.CreateOcspRequest(json,ocspRequest)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( http.LastErrorText) & "</pre>"
    Response.End
End If

'  Send the OCSP request to the OCSP server
set resp = Server.CreateObject("Chilkat.HttpResponse")
success = http.HttpBd("POST",ocspUrl,ocspRequest,"application/ocsp-request",resp)
If (success = 0) Then
    Response.Write "<pre>" & Server.HTMLEncode( http.LastErrorText) & "</pre>"
    Response.End
End If

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

'  Convert the binary reply to JSON.
'  Also returns the overall OCSP response status.
set jsonReply = Server.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
    Response.Write "<pre>" & Server.HTMLEncode( "Invalid OCSP reply.") & "</pre>"
    Response.End
End If

Response.Write "<pre>" & Server.HTMLEncode( "Overall OCSP Response Status: " & ocspStatus) & "</pre>"

'  Let's examine the OCSP response (in JSON).
jsonReply.EmitCompact = 0
Response.Write "<pre>" & Server.HTMLEncode( jsonReply.Emit()) & "</pre>"

'  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.
Response.Write "<pre>" & Server.HTMLEncode( "Certificate Status: " & certStatus) & "</pre>"

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