C

Validate Certificate using OCSP Protocol

See more Certificates Examples

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

#include <C_CkCert.h>
#include <C_CkPrng.h>
#include <C_CkJsonObject.h>
#include <C_CkBinData.h>
#include <C_CkHttp.h>
#include <C_CkHttpResponse.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkCert cert;
    const char *ocspUrl;
    const char *hashAlg;
    HCkPrng prng;
    HCkJsonObject json;
    HCkBinData ocspRequest;
    HCkHttp http;
    HCkHttpResponse resp;
    HCkBinData ocspReply;
    HCkJsonObject jsonReply;
    int ocspStatus;
    int certStatus;

    success = FALSE;

    //  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.
    cert = CkCert_Create();
    success = CkCert_LoadFromFile(cert,"qa_data/certs/google.crt");
    if (success == FALSE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkCert_Dispose(cert);
        return;
    }

    //  Get the cert's OCSP URL.
    ocspUrl = CkCert_ocspUrl(cert);

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

    //  Possible hash algorithms are sha1, sha256, sha384, sha512.  
    hashAlg = "sha256";
    prng = CkPrng_Create();
    json = CkJsonObject_Create();
    CkJsonObject_putEmitCompact(json,FALSE);
    //  Read more about OCSP nonce lengths
    CkJsonObject_UpdateString(json,"extensions.ocspNonce",CkPrng_genRandom(prng,16,"base64"));
    CkJsonObject_putI(json,0);
    CkJsonObject_UpdateString(json,"request[i].cert.hashAlg",hashAlg);
    CkJsonObject_UpdateString(json,"request[i].cert.issuerNameHash",CkCert_hashOf(cert,"IssuerDN",hashAlg,"base64"));
    CkJsonObject_UpdateString(json,"request[i].cert.issuerKeyHash",CkCert_hashOf(cert,"IssuerPublicKey",hashAlg,"base64"));
    CkJsonObject_UpdateString(json,"request[i].cert.serialNumber",CkCert_serialNumber(cert));

    printf("%s\n",CkJsonObject_emit(json));

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

    ocspRequest = CkBinData_Create();
    http = CkHttp_Create();

    //  Convert our JSON to a binary (ASN.1) OCSP request
    success = CkHttp_CreateOcspRequest(http,json,ocspRequest);
    if (success == FALSE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        CkCert_Dispose(cert);
        CkPrng_Dispose(prng);
        CkJsonObject_Dispose(json);
        CkBinData_Dispose(ocspRequest);
        CkHttp_Dispose(http);
        return;
    }

    //  Send the OCSP request to the OCSP server
    resp = CkHttpResponse_Create();
    success = CkHttp_HttpBd(http,"POST",ocspUrl,ocspRequest,"application/ocsp-request",resp);
    if (success == FALSE) {
        printf("%s\n",CkHttp_lastErrorText(http));
        CkCert_Dispose(cert);
        CkPrng_Dispose(prng);
        CkJsonObject_Dispose(json);
        CkBinData_Dispose(ocspRequest);
        CkHttp_Dispose(http);
        CkHttpResponse_Dispose(resp);
        return;
    }

    //  Get the binary (ASN.1) OCSP reply
    ocspReply = CkBinData_Create();
    CkHttpResponse_GetBodyBd(resp,ocspReply);

    //  Convert the binary reply to JSON.
    //  Also returns the overall OCSP response status.
    jsonReply = CkJsonObject_Create();
    ocspStatus = CkHttp_ParseOcspReply(http,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) {
        printf("Invalid OCSP reply.\n");
        CkCert_Dispose(cert);
        CkPrng_Dispose(prng);
        CkJsonObject_Dispose(json);
        CkBinData_Dispose(ocspRequest);
        CkHttp_Dispose(http);
        CkHttpResponse_Dispose(resp);
        CkBinData_Dispose(ocspReply);
        CkJsonObject_Dispose(jsonReply);
        return;
    }

    printf("Overall OCSP Response Status: %d\n",ocspStatus);

    //  Let's examine the OCSP response (in JSON).
    CkJsonObject_putEmitCompact(jsonReply,FALSE);
    printf("%s\n",CkJsonObject_emit(jsonReply));

    //  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 (CkJsonObject_HasMember(jsonReply,"response.cert[0].status") == TRUE) {
        certStatus = CkJsonObject_IntOf(jsonReply,"response.cert[0].status");
    }

    //  Possible certStatus values are:
    //  -1: No status returned.
    //  0: Good
    //  1: Revoked
    //  2: Unknown.
    printf("Certificate Status: %d\n",certStatus);


    CkCert_Dispose(cert);
    CkPrng_Dispose(prng);
    CkJsonObject_Dispose(json);
    CkBinData_Dispose(ocspRequest);
    CkHttp_Dispose(http);
    CkHttpResponse_Dispose(resp);
    CkBinData_Dispose(ocspReply);
    CkJsonObject_Dispose(jsonReply);

    }