Swift

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). Swift

func chilkatTest() {
    var success: Bool = false

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

    let pdf = CkoPdf()!

    // Load a PDF to be signed.
    // The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
    success = pdf.loadFile(filePath: "qa_data/pdf/hello.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    // Options for signing are specified in JSON.
    let json = CkoJsonObject()!

    // In most cases, the signingCertificateV2 and signingTime attributes are required.
    json.updateInt(jsonPath: "signingCertificateV2", value: 1)
    json.updateInt(jsonPath: "signingTime", value: 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".
    json.updateBool(jsonPath: "ltvOcsp", value: 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
    json.updateBool(jsonPath: "timestampToken.enabled", value: 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.
    json.updateString(jsonPath: "timestampToken.tsaUrl", value: "http://timestamp.digicert.com")

    // If the timestamp server requires a username/password, do the following.  Otherwise omit the following few lines of code.
    json.updateString(jsonPath: "timestampToken.tsaUsername", value: "the_tsa_username")
    json.updateString(jsonPath: "timestampToken.tsaPassword", value: "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.)
    json.updateBool(jsonPath: "timestampToken.requestTsaCert", value: true)

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

    // Load the signing certificate. (Use your own certificate.)
    let cert = CkoCert()!
    success = cert.loadPfxFile(path: "qa_data/pfx/myPdfSigningCert.pfx", password: "pfxPassword")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    // Tell the pdf object to use the certificate for signing.
    success = pdf.setSigningCert(cert: cert)
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    success = pdf.sign(jsonOptions: json, outFilePath: "qa_output/hello_ltv_signed_with_timestamp.pdf")
    if success == false {
        print("\(pdf.lastErrorText!)")
        return
    }

    print("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)

}