diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 77cbb52b..edb5e98e 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -130,6 +130,7 @@
+
diff --git a/ArcFormats/RPGMaker/ArcRGSS.cs b/ArcFormats/RPGMaker/ArcRGSS.cs
new file mode 100644
index 00000000..61ab3442
--- /dev/null
+++ b/ArcFormats/RPGMaker/ArcRGSS.cs
@@ -0,0 +1,178 @@
+//! \file ArcRGSS3.cs
+//! \date 2017 Nov 18
+//! \brief RPG Maker resource archive implementation.
+//
+// Copyright (C) 2017 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using System.IO;
+using System.Text;
+
+namespace GameRes.Formats.RPGMaker
+{
+ [Export(typeof(ArchiveFormat))]
+ public class RgssOpener : ArchiveFormat
+ {
+ public override string Tag { get { return "RGSSAD"; } }
+ public override string Description { get { return "RPG Maker engine resource archive"; } }
+ public override uint Signature { get { return 0x53534752; } } // 'RGSS'
+ public override bool IsHierarchic { get { return true; } }
+ public override bool CanWrite { get { return false; } }
+
+ public RgssOpener ()
+ {
+ Extensions = new string[] { "rgss3a", "rgss2a", "rgssad" };
+ }
+
+ public override ArcFile TryOpen (ArcView file)
+ {
+ if (!file.View.AsciiEqual (4, "AD\0"))
+ return null;
+ int version = file.View.ReadByte (7);
+ if (version != 3)
+ return null;
+ using (var index = file.CreateStream())
+ {
+ List dir = null;
+ if (3 == version)
+ dir = ReadIndexV3 (index);
+ else if (1 == version)
+ dir = ReadIndexV1 (index);
+ if (null == dir || 0 == dir.Count)
+ return null;
+ return new ArcFile (file, this, dir);
+ }
+ }
+
+ List ReadIndexV1 (IBinaryStream file)
+ {
+ var max_offset = file.Length;
+ file.Position = 8;
+ var key_gen = new KeyGenerator (0xDEADCAFE);
+ var dir = new List();
+ while (file.PeekByte() != -1)
+ {
+ uint name_length = file.ReadUInt32() ^ key_gen.GetNext();
+ var name_bytes = file.ReadBytes ((int)name_length);
+ var name = DecryptName (name_bytes, key_gen);
+ var entry = FormatCatalog.Instance.Create (name);
+ entry.Size = file.ReadUInt32() ^ key_gen.GetNext();
+ entry.Offset = file.Position;
+ entry.Key = key_gen.Current;
+ if (!entry.CheckPlacement (max_offset))
+ return null;
+ dir.Add (entry);
+ file.Seek (entry.Size, SeekOrigin.Current);
+ }
+ return dir;
+ }
+
+ List ReadIndexV3 (IBinaryStream file)
+ {
+ var max_offset = file.Length;
+ file.Position = 8;
+ uint key = file.ReadUInt32() * 9 + 3;
+ var dir = new List();
+ while (file.PeekByte() != -1)
+ {
+ uint offset = file.ReadUInt32() ^ key;
+ if (0 == offset)
+ break;
+ uint size = file.ReadUInt32() ^ key;
+ uint entry_key = file.ReadUInt32() ^ key;
+ uint name_length = file.ReadUInt32() ^ key;
+ var name_bytes = file.ReadBytes ((int)name_length);
+ var name = DecryptName (name_bytes, key);
+ var entry = FormatCatalog.Instance.Create (name);
+ entry.Offset = offset;
+ entry.Size = size;
+ entry.Key = entry_key;
+ if (!entry.CheckPlacement (max_offset))
+ return null;
+ dir.Add (entry);
+ }
+ return dir;
+ }
+
+ public override Stream OpenEntry (ArcFile arc, Entry entry)
+ {
+ var rent = (RgssEntry)entry;
+ var data = arc.File.View.ReadBytes (rent.Offset, rent.Size);
+ var key_gen = new KeyGenerator (rent.Key);
+ uint key = key_gen.GetNext();
+ for (int i = 0; i < data.Length; )
+ {
+ data[i] ^= (byte)(key >> (i << 3));
+ ++i;
+ if (0 == (i & 3))
+ {
+ key = key_gen.GetNext();
+ }
+ }
+ return new BinMemoryStream (data);
+ }
+
+ string DecryptName (byte[] name, KeyGenerator key_gen)
+ {
+ for (int i = 0; i < name.Length; ++i)
+ {
+ name[i] ^= (byte)key_gen.GetNext();
+ }
+ return Encoding.UTF8.GetString (name);
+ }
+
+ string DecryptName (byte[] name, uint key)
+ {
+ for (int i = 0; i < name.Length; ++i)
+ {
+ name[i] ^= (byte)(key >> (i << 3));
+ }
+ return Encoding.UTF8.GetString (name);
+ }
+ }
+
+ internal class RgssEntry : Entry
+ {
+ public uint Key;
+ }
+
+ internal class KeyGenerator
+ {
+ uint m_seed;
+
+ public KeyGenerator (uint seed)
+ {
+ m_seed = seed;
+ }
+
+ public uint Current { get { return m_seed; } }
+
+ public uint GetNext ()
+ {
+ uint key = m_seed;
+ m_seed = m_seed * 7 + 3;
+ return key;
+ }
+ }
+}