PDF_SignaturePermissions

using System;
using iText.Kernel.Pdf;
using iText.Signatures;

namespace pdf_isClosed
{
    class Program
    {
        static void Main(string[] args)
        {
            if (args.Length > 0)
            {
                foreach (String SRC in args)
                {
                    getCertificationLevel(SRC);
                }
            }
            else {
                getCertificationLevel(@"tryIt.pdf");
            }
        }

        static void getCertificationLevel( String SRC )
        {
            Console.WriteLine(SRC+Environment.NewLine);

            PdfReader reader = new PdfReader( SRC );
            PdfDocument doc = new PdfDocument( reader );
            SignatureUtil signUtil = new SignatureUtil(doc);

            if (signUtil.GetSignatureNames().Count == 0)
            {
                Console.WriteLine("There is no signature here.");
            }
            else
            {
                foreach (var sigName in signUtil.GetSignatureNames())
                {
                    PdfSignature signature = signUtil.GetSignature(sigName);

                    PdfDictionary dict = signUtil.GetSignatureDictionary(sigName); // https://stackoverflow.com/questions/58397100/itext7-c-sharp-check-pdf-was-locked-after-signature/58418033#58418033

                    SignaturePermissions perms = new SignaturePermissions(dict, null); // https://kb.itextpdf.com/itext/digital-signatures-chapter-5#Digitalsignatures-chapter5-c5_02_signatureinfo

                    Console.Write("\t" + sigName + "\n" +
                                  "\t" + signature.GetDate() + "\n" +
                                  "\t\t" + "IsCertification:      " + perms.IsCertification() + "\n" +
                                  "\t\t" + "IsFillInAllowed:      " + perms.IsFillInAllowed() + "\n" +
                                  "\t\t" + "IsAnnotationsAllowed: " + perms.IsAnnotationsAllowed() + "\n" +
                                  "\t\t" + "GetFieldLocks:        "
                                 );
                    if ( perms.GetFieldLocks().Count != 0 )
                        foreach (SignaturePermissions.FieldLock Lock in perms.GetFieldLocks()) { Console.Write( Lock + " " ); }
                    else
                        Console.Write( "-" );
                    Console.WriteLine("\n");


                    /*
                    //PdfSigner signer = new PdfSigner(doc); // 'PdfSigner' does not contain a constructor that takes 1 arguments
                    //var signerProperties = signer.GetSignerProperties(); // what creates a connection between PdfReader, PdfDocument, PdfSigner, or SignerProperties...???

                    SignerProperties sp = new SignerProperties();

                    switch ( sp.GetCertificationLevel() ) // https://api.itextpdf.com/iText/dotnet/9.0.0/namespacei_text_1_1_signatures.html#a996a04f7ae83f1a18712632be0460318
                    {
                        case AccessPermissions.UNSPECIFIED: // 0
                            Console.WriteLine("Unspecified access permissions value which makes signature 'approval' rather than 'certification'.");
                            break;
                        case AccessPermissions.NO_CHANGES_PERMITTED: // 1
                            Console.WriteLine("Access permissions level 1 which indicates that no changes are permitted except for DSS and DTS creation.");
                            break;
                        case AccessPermissions.FORM_FIELDS_MODIFICATION: // 2
                            Console.WriteLine("Access permissions level 2 which indicates that permitted changes, with addition to level 1, are: filling in forms, instantiating page templates, and signing. ");
                            break;
                        case AccessPermissions.ANNOTATION_MODIFICATION: // 3
                            Console.WriteLine("Access permissions level 3 which indicates that permitted changes, with addition to level 2, are: annotation creation, deletion and modification. ");
                            break;
                        default :
                            Console.WriteLine("WTF...?");
                            break;
                    } // switch
                    */


                } // foreach
            } // if
        } // getCertificationLevel()


    }
}