(DataFlex) Validate Certificate using OCSP Protocol

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

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

Use ChilkatAx-win32.pkg

Procedure Test
    Handle hoCert
    Boolean iSuccess
    String sOcspUrl
    String sHashAlg
    Handle hoPrng
    Variant vJson
    Handle hoJson
    Variant vOcspRequest
    Handle hoOcspRequest
    Handle hoHttp
    Variant vResp
    Handle hoResp
    Variant vOcspReply
    Handle hoOcspReply
    Variant vJsonReply
    Handle hoJsonReply
    Integer iOcspStatus
    Integer iCertStatus
    String sTemp1
    Boolean bTemp1

    // Note: Requires Chilkat v9.5.0.75 or greater.

    // 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.
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End
    Get ComLoadFromFile Of hoCert "qa_data/certs/google.crt" To iSuccess
    If (iSuccess <> True) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Get the cert's OCSP URL.
    Get ComOcspUrl Of hoCert To sOcspUrl

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

    // Possible hash algorithms are sha1, sha256, sha384, sha512.  
    Move "sha256" To sHashAlg
    Get Create (RefClass(cComChilkatPrng)) To hoPrng
    If (Not(IsComObjectCreated(hoPrng))) Begin
        Send CreateComObject of hoPrng
    End
    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End
    Set ComEmitCompact Of hoJson To False
    // Read more about OCSP nonce lengths
    Get ComGenRandom Of hoPrng 16 "base64" To sTemp1
    Get ComUpdateString Of hoJson "extensions.ocspNonce" sTemp1 To iSuccess
    Set ComI Of hoJson To 0
    Get ComUpdateString Of hoJson "request[i].cert.hashAlg" sHashAlg To iSuccess
    Get ComHashOf Of hoCert "IssuerDN" sHashAlg "base64" To sTemp1
    Get ComUpdateString Of hoJson "request[i].cert.issuerNameHash" sTemp1 To iSuccess
    Get ComHashOf Of hoCert "IssuerPublicKey" sHashAlg "base64" To sTemp1
    Get ComUpdateString Of hoJson "request[i].cert.issuerKeyHash" sTemp1 To iSuccess
    Get ComSerialNumber Of hoCert To sTemp1
    Get ComUpdateString Of hoJson "request[i].cert.serialNumber" sTemp1 To iSuccess

    Get ComEmit Of hoJson To sTemp1
    Showln sTemp1

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

    Get Create (RefClass(cComChilkatBinData)) To hoOcspRequest
    If (Not(IsComObjectCreated(hoOcspRequest))) Begin
        Send CreateComObject of hoOcspRequest
    End
    Get Create (RefClass(cComChilkatHttp)) To hoHttp
    If (Not(IsComObjectCreated(hoHttp))) Begin
        Send CreateComObject of hoHttp
    End

    // Convert our JSON to a binary (ASN.1) OCSP request
    Get pvComObject of hoJson to vJson
    Get pvComObject of hoOcspRequest to vOcspRequest
    Get ComCreateOcspRequest Of hoHttp vJson vOcspRequest To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Send the OCSP request to the OCSP server
    Get pvComObject of hoOcspRequest to vOcspRequest
    Get ComPBinaryBd Of hoHttp "POST" sOcspUrl vOcspRequest "application/ocsp-request" False False To vResp
    If (IsComObject(vResp)) Begin
        Get Create (RefClass(cComChilkatHttpResponse)) To hoResp
        Set pvComObject Of hoResp To vResp
    End
    Get ComLastMethodSuccess Of hoHttp To bTemp1
    If (bTemp1 <> True) Begin
        Get ComLastErrorText Of hoHttp To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Get the binary (ASN.1) OCSP reply
    Get Create (RefClass(cComChilkatBinData)) To hoOcspReply
    If (Not(IsComObjectCreated(hoOcspReply))) Begin
        Send CreateComObject of hoOcspReply
    End
    Get pvComObject of hoOcspReply to vOcspReply
    Get ComGetBodyBd Of hoResp vOcspReply To iSuccess
    Send Destroy of hoResp

    // Convert the binary reply to JSON.
    // Also returns the overall OCSP response status.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJsonReply
    If (Not(IsComObjectCreated(hoJsonReply))) Begin
        Send CreateComObject of hoJsonReply
    End
    Get pvComObject of hoOcspReply to vOcspReply
    Get pvComObject of hoJsonReply to vJsonReply
    Get ComParseOcspReply Of hoHttp vOcspReply vJsonReply To iOcspStatus

    // 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 (iOcspStatus < 0) Begin
        Showln "Invalid OCSP reply."
        Procedure_Return
    End

    Showln "Overall OCSP Response Status: " iOcspStatus

    // Let's examine the OCSP response (in JSON).
    Set ComEmitCompact Of hoJsonReply To False
    Get ComEmit Of hoJsonReply To sTemp1
    Showln sTemp1

    // 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:
    Move -1 To iCertStatus
    Get ComHasMember Of hoJsonReply "response.cert[0].status" To bTemp1
    If (bTemp1 = True) Begin
        Get ComIntOf Of hoJsonReply "response.cert[0].status" To iCertStatus
    End

    // Possible certStatus values are:
    // -1: No status returned.
    // 0: Good
    // 1: Revoked
    // 2: Unknown.
    Showln "Certificate Status: " iCertStatus


End_Procedure