DataFlex

Sign PDF with Long-Term Validation (LTV Enabled)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF with long-term validation (LTV) enabled.

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

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoPdf
    Variant vJson
    Handle hoJson
    Variant vCert
    Handle hoCert
    String sTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatPdf)) To hoPdf
    If (Not(IsComObjectCreated(hoPdf))) Begin
        Send CreateComObject of hoPdf
    End

    // Load a PDF to be signed.
    // The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    Get ComLoadFile Of hoPdf "qa_data/pdf/hello.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Options for signing are specified in JSON.
    Get Create (RefClass(cComChilkatJsonObject)) To hoJson
    If (Not(IsComObjectCreated(hoJson))) Begin
        Send CreateComObject of hoJson
    End

    // In most cases, the signingCertificateV2 and signingTime attributes are required.
    Get ComUpdateInt Of hoJson "signingCertificateV2" 1 To iSuccess
    Get ComUpdateInt Of hoJson "signingTime" 1 To iSuccess

    // Add the "ltvOcsp" instruction to the JSON passed to SignPdf.
    // This is what causes Chilkat to create an LTV-enabled signature.
    // 
    // If we are signing a PDF that already has signatures, then the existing signatures
    // are automatically verified, and Chilkat will do OCSP certificate status checking (if possible) 
    // for those certs in existing signatures (including certs in the certificate chains) 
    // that do not yet have a valid OCSP response in the DSS (Document Security Store).
    // Chilkat will add the OCSP responses to the /OCSPs in the Document Security Store (/DSS).
    // Also, and certificates from existing signatures not yet in the DSS are added to the /Certs 
    // in the DSS.
    // 
    // Also, the "ltvOcsp" causes Chilkat to add the pdfRevocationInfoArchival authenticated attribute
    // to the CMS signature.  The pdfRevocationInfoArchival attribute (1.2.840.113583.1.1.8)
    // contains OCSP responses and the CRL for the issuer of the signing certificate.
    // Therefore, Chilkat will send an OCSP request to the signing certificate's OCSP URl (if one exists)
    // and will download the CRL from the issuer certificate's CRL Distribution Point (if one exists).
    Get ComUpdateBool Of hoJson "ltvOcsp" True To iSuccess

    // -----------------------------------------------------------------------------------
    // Note: If Chilkat produces a signed PDF, but the signature is not LTV-enabled,
    // the cause might be related to a failure to download CRL's or OCSP requests.
    // See Possible Solution for Failure to Produce LTV-enabled PDF Signature
    // -----------------------------------------------------------------------------------
    // You can add the following to UncommonOptions to get detailed information about the CRL and OCSP requests
    // You shouldn't set the following logging options unless there is a need, because it adds a large amount of information to the LastErrorText.
    Set ComUncommonOptions Of hoPdf To "LOG_OCSP_HTTP,LOG_CRL_HTTP"

    // Define the appearance of the signature.
    Get ComUpdateInt Of hoJson "page" 1 To iSuccess
    Get ComUpdateString Of hoJson "appearance.y" "top" To iSuccess
    Get ComUpdateString Of hoJson "appearance.x" "left" To iSuccess
    Get ComUpdateString Of hoJson "appearance.fontScale" "10.0" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[0]" "Digitally signed by: cert_cn" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[1]" "current_dt" To iSuccess
    Get ComUpdateString Of hoJson "appearance.text[2]" "This is an LTV-enabled signature." To iSuccess

    // Load the signing certificate. (Use your own certificate.)
    Get Create (RefClass(cComChilkatCert)) To hoCert
    If (Not(IsComObjectCreated(hoCert))) Begin
        Send CreateComObject of hoCert
    End
    Get ComLoadPfxFile Of hoCert "qa_data/pfx/myPdfSigningCert.pfx" "pfxPassword" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoCert To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Tell the pdf object to use the certificate for signing.
    Get pvComObject of hoCert to vCert
    Get ComSetSigningCert Of hoPdf vCert To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get pvComObject of hoJson to vJson
    Get ComSignPdf Of hoPdf vJson "qa_output/hello_ltv_signed.pdf" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoPdf To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Showln "The PDF has been successfully cryptographically signed with long-term validation."

    // If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
    // as shown here:
    // (image:https://example-code.com/images/ltv_signature.jpg/endImage)


End_Procedure