(C) Sign PDF with Timestamp from TSA (Timestamp Server Authority)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF that is both long-term validation (LTV) enabled and includes a validating timestamp from a TSA (Timestamp Server Authority).

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

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#include <C_CkPdf.h>
#include <C_CkJsonObject.h>
#include <C_CkCert.h>

void ChilkatSample(void)
    {
    HCkPdf pdf;
    BOOL success;
    HCkJsonObject json;
    HCkCert cert;

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

    pdf = CkPdf_Create();

    // Load a PDF to be signed.
    // The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    success = CkPdf_LoadFile(pdf,"qa_data/pdf/hello.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        return;
    }

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

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

    // Tell Chilkat to create an LTV-enabled (long term validation) signature.
    // See PDF Long-Term Validation (LTV) Signature Example for more detailed comments about "ltvOcsp".
    CkJsonObject_UpdateBool(json,"ltvOcsp",TRUE);

    // Tell Chilkat to request a timestamp from a TSA server and include the timestamp token (1.2.840.113549.1.9.16.2.14)
    // in the CMS signature's authentication attributes
    CkJsonObject_UpdateBool(json,"timestampToken.enabled",TRUE);

    // In this example, we'll use a free TSA server (timestamp.digicert.com), but you may want to use your own timestamp authority server.
    CkJsonObject_UpdateString(json,"timestampToken.tsaUrl","http://timestamp.digicert.com");

    // If the timestamp server requires a username/password, do the following.  Otherwise omit the following few lines of code.
    CkJsonObject_UpdateString(json,"timestampToken.tsaUsername","the_tsa_username");
    CkJsonObject_UpdateString(json,"timestampToken.tsaPassword","the_tsa_password");

    // When requesting the timestamp token, ask the server to include its certificate in the timestamp token response.
    // This allows for the timestamp server's certificate to be included in the LTV validation (i.e. if the timestamp server
    // has an OCSP URL, then Chilkat will also do the OCSP request for the timestamp server's certificate.)
    CkJsonObject_UpdateBool(json,"timestampToken.requestTsaCert",TRUE);

    // Define the appearance of the signature.
    CkJsonObject_UpdateInt(json,"page",1);
    CkJsonObject_UpdateString(json,"appearance.y","top");
    CkJsonObject_UpdateString(json,"appearance.x","left");
    CkJsonObject_UpdateString(json,"appearance.fontScale","10.0");
    CkJsonObject_UpdateString(json,"appearance.text[0]","Digitally signed by: cert_cn");
    CkJsonObject_UpdateString(json,"appearance.text[1]","current_dt");
    CkJsonObject_UpdateString(json,"appearance.text[2]","This is an LTV-enabled signature with a TSA timestamp.");

    // Load the signing certificate. (Use your own certificate.)
    cert = CkCert_Create();
    success = CkCert_LoadPfxFile(cert,"qa_data/pfx/myPdfSigningCert.pfx","pfxPassword");
    if (success == FALSE) {
        printf("%s\n",CkCert_lastErrorText(cert));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkCert_Dispose(cert);
        return;
    }

    // Tell the pdf object to use the certificate for signing.
    success = CkPdf_SetSigningCert(pdf,cert);
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkCert_Dispose(cert);
        return;
    }

    success = CkPdf_SignPdf(pdf,json,"qa_output/hello_ltv_signed_with_timestamp.pdf");
    if (success == FALSE) {
        printf("%s\n",CkPdf_lastErrorText(pdf));
        CkPdf_Dispose(pdf);
        CkJsonObject_Dispose(json);
        CkCert_Dispose(cert);
        return;
    }

    printf("The PDF has been successfully cryptographically signed with TSA timestamp and long-term validation.\n");

    // If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
    // and contains an embedded timestamp:
    


    CkPdf_Dispose(pdf);
    CkJsonObject_Dispose(json);
    CkCert_Dispose(cert);

    }