DataFlex

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). 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

    // 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".
    Get ComUpdateBool Of hoJson "ltvOcsp" True To iSuccess

    // 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
    Get ComUpdateBool Of hoJson "timestampToken.enabled" True To iSuccess

    // In this example, we'll use a free TSA server (timestamp.digicert.com), but you may want to use your own timestamp authority server.
    Get ComUpdateString Of hoJson "timestampToken.tsaUrl" "http://timestamp.digicert.com" To iSuccess

    // If the timestamp server requires a username/password, do the following.  Otherwise omit the following few lines of code.
    Get ComUpdateString Of hoJson "timestampToken.tsaUsername" "the_tsa_username" To iSuccess
    Get ComUpdateString Of hoJson "timestampToken.tsaPassword" "the_tsa_password" To iSuccess

    // 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.)
    Get ComUpdateBool Of hoJson "timestampToken.requestTsaCert" True To iSuccess

    // 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 with a TSA timestamp." 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_with_timestamp.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 TSA timestamp and long-term validation."

    // If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
    // and contains an embedded timestamp:
    // (image:https://example-code.com/images/ltv_signature_with_timestamp.jpg/endImage)


End_Procedure