implemented DPK resource archives.

known encryption keys for:
Inbou no Wakusei
Ryoshuu
Ryobaku ~Haitoku no Atelier~
Ryoshuu ~Jogakusei Choukyou~
Shirogane no Cal to Soukuu no Joou
Shiromiko
Shoujotachi no Saezuri
Yumemiru Tsuki no Lunalutia

ArcFormats/Strings/arcStrings.Designer.cs

@@ -133,6 +133,24 @@ namespace GameRes.Formats.Strings {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Encryption scheme.
+        /// </summary>
+        public static string ArcScheme {
+            get {
+                return ResourceManager.GetString("ArcScheme", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Encryption keys.
+        /// </summary>
+        public static string DPKKeys {
+            get {
+                return ResourceManager.GetString("DPKKeys", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to âge proprietary image format.
         /// </summary>

ArcFormats/Strings/arcStrings.resx

@@ -318,4 +318,10 @@ Enter archive encryption key.</value>
   <data name="NOAIgnoreEncryption" xml:space="preserve">
     <value>Ignore encryption</value>
   </data>
+  <data name="ArcScheme" xml:space="preserve">
+    <value>Encryption scheme</value>
+  </data>
+  <data name="DPKKeys" xml:space="preserve">
+    <value>Encryption keys</value>
+  </data>
 </root>

ArcFormats/Strings/arcStrings.ru-RU.resx

@@ -139,6 +139,12 @@
   <data name="ArcReset" xml:space="preserve">
     <value>Сбросить</value>
   </data>
+  <data name="ArcScheme" xml:space="preserve">
+    <value>Способ шифрования</value>
+  </data>
+  <data name="DPKKeys" xml:space="preserve">
+    <value>Ключи шифрования</value>
+  </data>
   <data name="INTCreationNotice" xml:space="preserve">
     <value>Создание зашифрованных архивов не реализовано.</value>
   </data>