(KiriKiri): implemented Natsupochi encryption.

ArcFormats/KiriKiri/ArcXP3.cs

@@ -1171,4 +1171,27 @@ NextEntry:
             Decrypt (entry, offset, values, pos, count);
         }
     }
+
+    [Serializable]
+    public class NatsupochiCrypt : ICrypt
+    {
+        public override byte Decrypt (Xp3Entry entry, long offset, byte value)
+        {
+            return (byte)(value ^ (entry.Hash >> 3));
+        }
+
+        public override void Decrypt (Xp3Entry entry, long offset, byte[] values, int pos, int count)
+        {
+            byte key = (byte)(entry.Hash >> 3);
+            for (int i = 0; i < count; ++i)
+            {
+                values[pos+i] ^= key;
+            }
+        }
+
+        public override void Encrypt (Xp3Entry entry, long offset, byte[] values, int pos, int count)
+        {
+            Decrypt (entry, offset, values, pos, count);
+        }
+    }
 }

supported.html

@@ -170,6 +170,8 @@ Hanafubuki ~Sennen no Koi o Shimashita~<br/>
 Haruiro ☆ Communication ♪<br/>
 Hime to Majin to Koi Suru Tamashii<br/>
 Imouto Style<br/>
+Natsupochi<br/>
+Nidaime wa ☆ Mahou Shoujo<br/>
 Nuki Doki!<br/>
 Okiba ga Nai!<br/>
 Ore no Saimin Fantasia<br/>