Lianja Requires Chilkat v11.0.0+

Validate Certificate using OCSP Protocol

See more Certificates Examples

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

llSuccess = .F.

//  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.
loCert = createobject("CkCert")
llSuccess = loCert.LoadFromFile("qa_data/certs/google.crt")
if (llSuccess = .F.) then
    ? loCert.LastErrorText
    release loCert
    return
endif

//  Get the cert's OCSP URL.
lcOcspUrl = loCert.OcspUrl

//  Build the JSON that will be the OCSP request.

//  Possible hash algorithms are sha1, sha256, sha384, sha512.  
lcHashAlg = "sha256"
loPrng = createobject("CkPrng")
loJson = createobject("CkJsonObject")
loJson.EmitCompact = .F.
//  Read more about OCSP nonce lengths
loJson.UpdateString("extensions.ocspNonce",loPrng.GenRandom(16,"base64"))
loJson.I = 0
loJson.UpdateString("request[i].cert.hashAlg",lcHashAlg)
loJson.UpdateString("request[i].cert.issuerNameHash",loCert.HashOf("IssuerDN",lcHashAlg,"base64"))
loJson.UpdateString("request[i].cert.issuerKeyHash",loCert.HashOf("IssuerPublicKey",lcHashAlg,"base64"))
loJson.UpdateString("request[i].cert.serialNumber",loCert.SerialNumber)

? loJson.Emit()

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

loOcspRequest = createobject("CkBinData")
loHttp = createobject("CkHttp")

//  Convert our JSON to a binary (ASN.1) OCSP request
llSuccess = loHttp.CreateOcspRequest(loJson,loOcspRequest)
if (llSuccess = .F.) then
    ? loHttp.LastErrorText
    release loCert
    release loPrng
    release loJson
    release loOcspRequest
    release loHttp
    return
endif

//  Send the OCSP request to the OCSP server
loResp = createobject("CkHttpResponse")
llSuccess = loHttp.HttpBd("POST",lcOcspUrl,loOcspRequest,"application/ocsp-request",loResp)
if (llSuccess = .F.) then
    ? loHttp.LastErrorText
    release loCert
    release loPrng
    release loJson
    release loOcspRequest
    release loHttp
    release loResp
    return
endif

//  Get the binary (ASN.1) OCSP reply
loOcspReply = createobject("CkBinData")
loResp.GetBodyBd(loOcspReply)

//  Convert the binary reply to JSON.
//  Also returns the overall OCSP response status.
loJsonReply = createobject("CkJsonObject")
lnOcspStatus = loHttp.ParseOcspReply(loOcspReply,loJsonReply)

//  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 (lnOcspStatus < 0) then
    ? "Invalid OCSP reply."
    release loCert
    release loPrng
    release loJson
    release loOcspRequest
    release loHttp
    release loResp
    release loOcspReply
    release loJsonReply
    return
endif

? "Overall OCSP Response Status: " + str(lnOcspStatus)

//  Let's examine the OCSP response (in JSON).
loJsonReply.EmitCompact = .F.
? loJsonReply.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:
lnCertStatus = -1
if (loJsonReply.HasMember("response.cert[0].status") = .T.) then
    lnCertStatus = loJsonReply.IntOf("response.cert[0].status")
endif

//  Possible certStatus values are:
//  -1: No status returned.
//  0: Good
//  1: Revoked
//  2: Unknown.
? "Certificate Status: " + str(lnCertStatus)


release loCert
release loPrng
release loJson
release loOcspRequest
release loHttp
release loResp
release loOcspReply
release loJsonReply