Make PdfEncryption constants internal to avoid confusions with PdfWriter.ENCRYPTION_XYZ constants

Author: VahidN

src/iTextSharp.LGPLv2.Core/iTextSharp.LGPLv2.Core.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
     <PropertyGroup>
         <Description>iTextSharp.LGPLv2.Core is an unofficial port of the last LGPL version of the iTextSharp (V4.1.6) to .NET Core.</Description>
-        <VersionPrefix>3.7.1</VersionPrefix>
+        <VersionPrefix>3.7.2</VersionPrefix>
         <Authors>Vahid Nasiri</Authors>
         <TargetFrameworks>net9.0;net8.0;net7.0;net6.0;netstandard2.0;net462;</TargetFrameworks>
         <GenerateDocumentationFile>true</GenerateDocumentationFile>

src/iTextSharp.LGPLv2.Core/iTextSharp/text/pdf/PdfEncryption.cs

@@ -14,11 +14,11 @@ namespace iTextSharp.text.pdf;
 /// </summary>
 public class PdfEncryption
 {
-    public const int STANDARD_ENCRYPTION_40 = 2;
-    public const int STANDARD_ENCRYPTION_128 = 3;
-    public const int AES_128 = 4;
-    public const int AES_256 = 5;
-    public const int AES_256_V3 = 6;
+    internal const int STANDARD_ENCRYPTION_40 = 2;
+    internal const int STANDARD_ENCRYPTION_128 = 3;
+    internal const int AES_128 = 4;
+    internal const int AES_256 = 5;
+    internal const int AES_256_V3 = 6;
 
     private const int VALIDATION_SALT_OFFSET = 32;
     private const int KEY_SALT_OFFSET = 40;