Unicode C

Sign PDF with Invisible Signature

See more PDF Signatures Examples

Demonstrates how to sign a PDF with an invisible signature.

Note: This example requires Chilkat v9.5.0.85 or greater.

Unicode C

#include <C_CkPdfW.h>
#include <C_CkJsonObjectW.h>
#include <C_CkCertW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPdfW pdf;
    HCkJsonObjectW json;
    HCkCertW cert;

    success = FALSE;

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

    pdf = CkPdfW_Create();

    //  Load a PDF to be signed.
    //  The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    success = CkPdfW_LoadFile(pdf,L"qa_data/pdf/hello.pdf");
    if (success == FALSE) {
        wprintf(L"%s\n",CkPdfW_lastErrorText(pdf));
        CkPdfW_Dispose(pdf);
        return;
    }

    //  Options for signing are specified in JSON.
    json = CkJsonObjectW_Create();

    //  In most cases, the signingCertificateV2 and signingTime attributes are required.
    CkJsonObjectW_UpdateInt(json,L"signingCertificateV2",1);
    CkJsonObjectW_UpdateInt(json,L"signingTime",1);

    //  Indicate that the signature will be invisible.
    CkJsonObjectW_UpdateBool(json,L"invisibleSignature",TRUE);

    //  Load the signing certificate. (Use your own certificate.)
    cert = CkCertW_Create();
    success = CkCertW_LoadPfxFile(cert,L"qa_data/pfx/myPdfSigningCert.pfx",L"secret");
    if (success == FALSE) {
        wprintf(L"%s\n",CkCertW_lastErrorText(cert));
        CkPdfW_Dispose(pdf);
        CkJsonObjectW_Dispose(json);
        CkCertW_Dispose(cert);
        return;
    }

    //  Tell the pdf object to use the certificate for signing.
    success = CkPdfW_SetSigningCert(pdf,cert);
    if (success == FALSE) {
        wprintf(L"%s\n",CkPdfW_lastErrorText(pdf));
        CkPdfW_Dispose(pdf);
        CkJsonObjectW_Dispose(json);
        CkCertW_Dispose(cert);
        return;
    }

    success = CkPdfW_SignPdf(pdf,json,L"qa_output/hello_signed.pdf");
    if (success == FALSE) {
        wprintf(L"%s\n",CkPdfW_lastErrorText(pdf));
        CkPdfW_Dispose(pdf);
        CkJsonObjectW_Dispose(json);
        CkCertW_Dispose(cert);
        return;
    }

    wprintf(L"PDF successfully signed with an invisible signature.\n");

    //  An invisible signature has no appearance within the PDF document itself,
    //  but Adobe Acrobat will indicate the document is signed in a toolbar, as shown here:
    //  (image:https://example-code.com/images/invisible_signature.jpg/endImage)


    CkPdfW_Dispose(pdf);
    CkJsonObjectW_Dispose(json);
    CkCertW_Dispose(cert);

    }