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

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

loPdf = createobject("CkPdf")

// Load a PDF to be signed.
// The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
llSuccess = loPdf.LoadFile("qa_data/pdf/hello.pdf")
if (llSuccess = .F.) then
    ? loPdf.LastErrorText
    release loPdf
    return
endif

// Options for signing are specified in JSON.
loJson = createobject("CkJsonObject")

// In most cases, the signingCertificateV2 and signingTime attributes are required.
loJson.UpdateInt("signingCertificateV2",1)
loJson.UpdateInt("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".
loJson.UpdateBool("ltvOcsp",.T.)

// 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
loJson.UpdateBool("timestampToken.enabled",.T.)

// In this example, we'll use a free TSA server (timestamp.digicert.com), but you may want to use your own timestamp authority server.
loJson.UpdateString("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.
loJson.UpdateString("timestampToken.tsaUsername","the_tsa_username")
loJson.UpdateString("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.)
loJson.UpdateBool("timestampToken.requestTsaCert",.T.)

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

// Load the signing certificate. (Use your own certificate.)
loCert = createobject("CkCert")
llSuccess = loCert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","pfxPassword")
if (llSuccess = .F.) then
    ? loCert.LastErrorText
    release loPdf
    release loJson
    release loCert
    return
endif

// Tell the pdf object to use the certificate for signing.
llSuccess = loPdf.SetSigningCert(loCert)
if (llSuccess = .F.) then
    ? loPdf.LastErrorText
    release loPdf
    release loJson
    release loCert
    return
endif

llSuccess = loPdf.SignPdf(loJson,"qa_output/hello_ltv_signed_with_timestamp.pdf")
if (llSuccess = .F.) then
    ? loPdf.LastErrorText
    release loPdf
    release loJson
    release loCert
    return
endif

? "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:



release loPdf
release loJson
release loCert