Node.js Requires Chilkat v11.7.0+

Encrypt and Sign a PDF, and Sign an Encrypted PDF

See more PDF Protection Examples

Demonstrates signing together with encryption. A pending encrypt is applied by SignPdf before it signs, so one call produces a PDF that is both encrypted and signed. A PDF that is already encrypted can be signed too, and stays encrypted. When it was opened with only the user password its permissions decide: adding a signature field needs both the modify and the annotate permission. Loading the PDF with its owner password lifts that. Node.js

NODEJS_PRELUDE

function chilkatExample() {

    var success = false;

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

    //  The PDF used in this example is available at two_page_memo.pdf

    //  The signing certificate, with its private key.
    var cert = new chilkat.Cert();
    success = cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret");
    if (success == false) {
        console.log(cert.LastErrorText);
        return;
    }

    var pdf = new chilkat.Pdf();
    success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf");
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    //  Encrypt with AES-256 and do not permit modifying.
    pdf.UserPassword = "user-secret";
    pdf.OwnerPassword = "owner-secret";
    var json = new chilkat.JsonObject();
    json.UpdateBool("permissions.modify",false);
    var jsonOut = new chilkat.JsonObject();
    success = pdf.Protection("encrypt",json,jsonOut);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    //  The encryption is still pending.  SignPdf applies it first and signs the encrypted result.
    success = pdf.SetSigningCert(cert);
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    var sigOpts = new chilkat.JsonObject();
    sigOpts.UpdateBool("invisibleSignature",true);
    sigOpts.UpdateInt("signingCertificateV2",1);
    sigOpts.UpdateInt("signingTime",1);
    success = pdf.SignPdf(sigOpts,"qa_output/memo_encrypted_signed.pdf");
    if (success == false) {
        console.log(pdf.LastErrorText);
        return;
    }

    //  The result is encrypted and signed.
    var check = new chilkat.Pdf();
    check.UserPassword = "user-secret";
    success = check.LoadFile("qa_output/memo_encrypted_signed.pdf");
    if (success == false) {
        console.log(check.LastErrorText);
        return;
    }

    var empty = new chilkat.JsonObject();
    var info = new chilkat.JsonObject();
    success = check.Protection("getInfo",empty,info);
    if (success == false) {
        console.log(check.LastErrorText);
        return;
    }

    console.log("algorithm: " + info.StringOf("loaded.algorithm"));
    console.log("signatures: " + check.NumSignatures);
    var sigInfo = new chilkat.JsonObject();
    var verified = check.VerifySignature(0,sigInfo);
    console.log("signature verifies: " + verified);

    //  Signing an encrypted PDF.  This one was opened with only the user password, and its
    //  permissions do not allow modifying, so another signature is refused.
    success = check.SetSigningCert(cert);
    if (success == false) {
        console.log(check.LastErrorText);
        return;
    }

    success = check.SignPdf(sigOpts,"qa_output/memo_signed_twice.pdf");
    if (success == false) {
        console.log("A second signature was refused: the permissions do not allow it.");
    }

    //  Loaded with the owner password, the same PDF can be signed.  It stays encrypted, and the
    //  first signature stays valid because the new one is added as an incremental update.
    var owner = new chilkat.Pdf();
    owner.UserPassword = "user-secret";
    owner.OwnerPassword = "owner-secret";
    success = owner.LoadFile("qa_output/memo_encrypted_signed.pdf");
    if (success == false) {
        console.log(owner.LastErrorText);
        return;
    }

    success = owner.SetSigningCert(cert);
    if (success == false) {
        console.log(owner.LastErrorText);
        return;
    }

    success = owner.SignPdf(sigOpts,"qa_output/memo_signed_twice.pdf");
    if (success == false) {
        console.log(owner.LastErrorText);
        return;
    }

    var twice = new chilkat.Pdf();
    twice.UserPassword = "user-secret";
    success = twice.LoadFile("qa_output/memo_signed_twice.pdf");
    if (success == false) {
        console.log(twice.LastErrorText);
        return;
    }

    console.log("signatures after signing with owner rights: " + twice.NumSignatures);
    verified = twice.VerifySignature(0,sigInfo);
    console.log("first signature still verifies: " + verified);
    verified = twice.VerifySignature(1,sigInfo);
    console.log("second signature verifies: " + verified);

    //  Sample output:

    //  algorithm: aes-256
    //  signatures: 1
    //  signature verifies: True
    //  A second signature was refused: the permissions do not allow it.
    //  signatures after signing with owner rights: 2
    //  first signature still verifies: True
    //  second signature verifies: True

}

chilkatExample();