changed the use of PdfName constructor to predefined constants

Autoported commit.
Original commit hash: [53686f9d30]

Author: michaeldemey

itext/itext.kernel/itext/kernel/pdf/PdfName.cs

@@ -940,6 +940,8 @@ public class PdfName : PdfPrimitiveObject, IComparable<iText.Kernel.Pdf.PdfName>
 
         public static readonly iText.Kernel.Pdf.PdfName MCR = CreateDirectName("MCR");
 
+        public static readonly iText.Kernel.Pdf.PdfName MD5 = CreateDirectName("MD5");
+
         public static readonly iText.Kernel.Pdf.PdfName Measure = CreateDirectName("Measure");
 
         public static readonly iText.Kernel.Pdf.PdfName MediaBox = CreateDirectName("MediaBox");

itext/itext.sign/itext/signatures/PdfSigner.cs

@@ -973,12 +973,12 @@ protected internal virtual void AddDocMDP(PdfSignature crypto) {
             reference.Put(PdfName.Type, PdfName.SigRef);
             reference.Put(PdfName.TransformParams, transformParams);
             if (document.GetPdfVersion().CompareTo(PdfVersion.PDF_1_6) < 0) {
-                reference.Put(new PdfName("DigestValue"), new PdfString("aa"));
+                reference.Put(PdfName.DigestValue, new PdfString("aa"));
                 PdfArray loc = new PdfArray();
                 loc.Add(new PdfNumber(0));
                 loc.Add(new PdfNumber(0));
-                reference.Put(new PdfName("DigestLocation"), loc);
-                reference.Put(new PdfName("DigestMethod"), new PdfName("MD5"));
+                reference.Put(PdfName.DigestLocation, loc);
+                reference.Put(PdfName.DigestMethod, PdfName.MD5);
             }
             reference.Put(PdfName.Data, document.GetTrailer().Get(PdfName.Root));
             PdfArray types = new PdfArray();
@@ -1001,12 +1001,12 @@ protected internal virtual void AddFieldMDP(PdfSignature crypto, PdfSigFieldLock
             reference.Put(PdfName.TransformMethod, PdfName.FieldMDP);
             reference.Put(PdfName.Type, PdfName.SigRef);
             reference.Put(PdfName.TransformParams, transformParams);
-            reference.Put(new PdfName("DigestValue"), new PdfString("aa"));
+            reference.Put(PdfName.DigestValue, new PdfString("aa"));
             PdfArray loc = new PdfArray();
             loc.Add(new PdfNumber(0));
             loc.Add(new PdfNumber(0));
-            reference.Put(new PdfName("DigestLocation"), loc);
-            reference.Put(new PdfName("DigestMethod"), new PdfName("MD5"));
+            reference.Put(PdfName.DigestLocation, loc);
+            reference.Put(PdfName.DigestMethod, PdfName.MD5);
             reference.Put(PdfName.Data, document.GetTrailer().Get(PdfName.Root));
             PdfArray types = crypto.GetPdfObject().GetAsArray(PdfName.Reference);
             if (types == null) {

port-hash

@@ -1 +1 @@
-22d027c71be0b8c0e40fa2ea4f509b01067c3578
+53686f9d309344c2464c5c221fdab4f967f8a039