diff --git a/ArcFormats/ArcDRS.cs b/ArcFormats/ArcDRS.cs
index 902af1e4..96a8477b 100644
--- a/ArcFormats/ArcDRS.cs
+++ b/ArcFormats/ArcDRS.cs
@@ -23,12 +23,15 @@
 // IN THE SOFTWARE.
 //
 
+using System;
 using System.IO;
 using System.Linq;
 using System.Text;
 using System.Collections.Generic;
 using System.ComponentModel.Composition;
+using GameRes.Utility;
 using GameRes.Formats.Strings;
+using GameRes.Formats.Properties;
 
 namespace GameRes.Formats.DRS
 {
@@ -90,6 +93,22 @@ namespace GameRes.Formats.DRS
         }
     }
 
+    internal class IsfOptions : ResourceOptions
+    {
+        public byte[] Secret;
+    }
+
+    internal class IsfArchive : ArcFile
+    {
+        public byte[] Secret;
+
+        public IsfArchive (ArcView arc, ArchiveFormat impl, ICollection<Entry> dir, byte[] secret = null)
+            : base (arc, impl, dir)
+        {
+            Secret = secret;
+        }
+    }
+
     [Export(typeof(ArchiveFormat))]
     public class MpxOpener : ArchiveFormat
     {
@@ -119,6 +138,7 @@ namespace GameRes.Formats.DRS
 
             long dir_offset = 0x20;
             var dir = new List<Entry> (count);
+            bool has_scripts = false;
             for (int i = 0; i < count; ++i)
             {
                 file.View.Read (dir_offset, name_raw, 0, 12);
@@ -129,8 +149,11 @@ namespace GameRes.Formats.DRS
                     return null;
                 string name = encoding.GetString (name_raw, 0, name_length).ToLowerInvariant();
                 Entry entry;
-                if (name.EndsWith (".isf", System.StringComparison.InvariantCultureIgnoreCase))
+                if (name.EndsWith (".isf") || name.EndsWith (".snr"))
+                {
                     entry = new Entry { Name = name, Type = "script" };
+                    has_scripts = true;
+                }
                 else
                     entry = FormatCatalog.Instance.CreateEntry (name);
                 entry.Offset = file.View.ReadUInt32 (dir_offset+12);
@@ -140,7 +163,179 @@ namespace GameRes.Formats.DRS
                 dir.Add (entry);
                 dir_offset += 0x14;
             }
-            return new ArcFile (file, this, dir);
+            if (has_scripts)
+                return new IsfArchive (file, this, dir);
+            else
+                return new ArcFile (file, this, dir);
         }
+
+        public override Stream OpenEntry (ArcFile arc, Entry entry)
+        {
+            if (!(arc is IsfArchive) || entry.Type != "script" || entry.Size < 0x10)
+                return arc.File.CreateStream (entry.Offset, entry.Size);
+            bool encoded = arc.File.View.AsciiEqual (entry.Offset+entry.Size-0x10, "SECRETFILTER100a");
+            uint entry_size = entry.Size;
+            var isf = arc as IsfArchive;
+            if (encoded)
+            {
+                entry_size -= 0x10;
+                if (null == isf.Secret)
+                    isf.Secret = QuerySecret();
+                if (null == isf.Secret || 0 == isf.Secret.Length)
+                    return arc.File.CreateStream (entry.Offset, entry.Size);
+            }
+            var data = new byte[entry_size];
+            arc.File.View.Read (entry.Offset, data, 0, entry_size);
+            if (encoded)
+            {
+                var decoder = new IsfDecoder (isf.Secret);
+                decoder.Decode (data);
+            }
+            int signature = LittleEndian.ToUInt16 (data, 4);
+            if (0x9795 == signature)
+            {
+                ApplyTransformation (data, 8, x => x >> 2 | x << 6);
+            }
+            else if (0xd197 == signature)
+            {
+                ApplyTransformation (data, 8, x => ~x);
+            }
+            else if (0xce89 == signature && 0 != data[6])
+            {
+                byte key = data[6];
+                ApplyTransformation (data, 8, x => x ^ key);
+            }
+            return new MemoryStream (data);
+        }
+
+        public override ResourceOptions GetDefaultOptions ()
+        {
+            return new IsfOptions {
+                Secret = GetSecret (Settings.Default.ISFScheme),
+            };
+        }
+
+        public override object GetAccessWidget ()
+        {
+            return new GUI.WidgetISF();
+        }
+
+        private byte[] QuerySecret ()
+        {
+            var options = Query<IsfOptions> (arcStrings.ArcEncryptedNotice);
+            return options.Secret;
+        }
+
+        private static byte[] GetSecret (string scheme)
+        {
+            byte[] secret;
+            if (KnownSecrets.TryGetValue (scheme, out secret))
+                return secret;
+            return null;
+        }
+
+        private static void ApplyTransformation (byte[] data, int offset, Func<byte, int> method)
+        {
+            for (int i = offset; i < data.Length; ++i)
+                data[i] = (byte)method (data[i]);
+        }
+
+        public static readonly Dictionary<string, byte[]> KnownSecrets = new Dictionary<string, byte[]>
+        {
+            { arcStrings.ISFIgnoreEncryption, new byte[0] },
+            { "Anata no Osanazuma", Encoding.ASCII.GetBytes("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") },
+            { "Natsu no Hitoshizuku", Encoding.ASCII.GetBytes("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") },
+        };
+    }
+
+    internal class IsfDecoder
+    {
+        byte[]      m_secret;
+
+        public IsfDecoder (byte[] secret)
+        {
+            m_secret = secret;
+        }
+
+        public void Decode (byte[] data)
+        {
+            var key_string = CreateKeyString();
+            int n = 0;
+            for (int i = 0; i < data.Length; )
+            {
+                DecodePrepare (n++, key_string);
+                for (int j = 0; j < key_string.Length && i < data.Length; )
+                {
+                    data[i++] ^= key_string[j++];
+                }
+            }
+        }
+
+        private byte[] CreateKeyString ()
+        {
+            byte[] len_str = new byte[2];
+            for (int i = 0; i < 2; i++)
+                len_str[i] = EncodeHex ((byte)(Chr2HexCode (m_secret[0x500 + i]) - Chr2HexCode (m_secret[0x100 + i])));
+
+            byte[] key_string = new byte[Str2Hex (len_str)];
+            for (int i = 0; i < key_string.Length; i++)
+                key_string[i] = EncodeHex ((byte)(Chr2HexCode (m_secret[0x510 + i]) - Chr2HexCode (m_secret[0x110 + i])));
+            return key_string;
+        }
+
+        private void DecodePrepare (int index, byte[] key_string)
+        {
+            int p = (index & 0x3f) * 16; // index within SecretTable
+            for (int i = 0; i < key_string.Length; i++)
+                key_string[i] = EncodeHex ((byte)(Chr2HexCode (key_string[i]) + Chr2HexCode (m_secret[p+i])));
+        }
+
+        private static byte EncodeHex (byte symbol)
+        {
+            if (symbol < 0x80)
+                return HexEncodeMap[symbol % 36];
+            symbol = (byte)(-(sbyte)symbol % 36);
+            if (0 == symbol)
+                return HexEncodeMap[0];
+            return HexEncodeMap[36 - symbol];
+        }
+
+        private static byte Chr2HexCode (byte chr)
+        {
+            return HexTable[Chr2Hex (chr)];
+        }
+
+        private static byte Chr2Hex (byte chr)
+        {
+            byte code;
+            if (chr >= '0' && chr <= '9')
+                code = (byte)(chr - '0');
+            else if (chr >= 'a' && chr <= 'z')
+                code = (byte)(chr - 'a' + 10);
+            else if (chr >= 'A' && chr <= 'Z')
+                code = (byte)(chr - 'A' + 10);
+            else
+                code = 0;
+            return code;
+        }
+
+        private static int Str2Hex (byte[] shex)
+        {
+            int idec = 0;
+            for (int i = 0; i < shex.Length; ++i)
+            {
+                int mid = Chr2Hex (shex[i]);
+                mid <<= ((shex.Length - i - 1) << 2);
+                idec |= mid;
+            }
+            return idec;
+        }
+
+        static readonly byte[] HexEncodeMap = Encoding.ASCII.GetBytes("G5FXIL094MPRKWCJ3OEBVA7HQ2SU8Y6TZ1ND");
+        static readonly byte[] HexTable = new byte[] {
+            0x06, 0x21, 0x19, 0x10, 0x08, 0x01, 0x1E, 0x16, 0x1C, 0x07, 0x15, 0x13, 0x0E, 0x23, 0x12, 0x02,
+            0x00, 0x17, 0x04, 0x0F, 0x0C, 0x05, 0x09, 0x22, 0x11, 0x0A, 0x18, 0x0B, 0x1A, 0x1F, 0x1B, 0x14,
+            0x0D, 0x03, 0x1D, 0x20,
+        };
     }
 }
diff --git a/ArcFormats/ArcFormats.csproj b/ArcFormats/ArcFormats.csproj
index 7ff648f9..bfc93971 100644
--- a/ArcFormats/ArcFormats.csproj
+++ b/ArcFormats/ArcFormats.csproj
@@ -221,6 +221,9 @@
     <Compile Include="WidgetINT.xaml.cs">
       <DependentUpon>WidgetINT.xaml</DependentUpon>
     </Compile>
+    <Compile Include="WidgetISF.xaml.cs">
+      <DependentUpon>WidgetISF.xaml</DependentUpon>
+    </Compile>
     <Compile Include="WidgetKCAP.xaml.cs">
       <DependentUpon>WidgetKCAP.xaml</DependentUpon>
     </Compile>
@@ -327,6 +330,10 @@
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
     </Page>
+    <Page Include="WidgetISF.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="WidgetKCAP.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
diff --git a/ArcFormats/Properties/AssemblyInfo.cs b/ArcFormats/Properties/AssemblyInfo.cs
index fd4af8d4..d8fb68b2 100644
--- a/ArcFormats/Properties/AssemblyInfo.cs
+++ b/ArcFormats/Properties/AssemblyInfo.cs
@@ -32,5 +32,5 @@ using System.Runtime.InteropServices;
 // You can specify all the values or you can default the Build and Revision Numbers 
 // by using the '*' as shown below:
 // [assembly: AssemblyVersion("1.0.*")]
-[assembly: AssemblyVersion ("1.0.7.65")]
-[assembly: AssemblyFileVersion ("1.0.7.65")]
+[assembly: AssemblyVersion ("1.0.7.66")]
+[assembly: AssemblyFileVersion ("1.0.7.66")]
diff --git a/ArcFormats/Properties/Settings.Designer.cs b/ArcFormats/Properties/Settings.Designer.cs
index 75a85724..4c44636b 100644
--- a/ArcFormats/Properties/Settings.Designer.cs
+++ b/ArcFormats/Properties/Settings.Designer.cs
@@ -369,5 +369,17 @@ namespace GameRes.Formats.Properties {
                 this["MBLPassPhrase"] = value;
             }
         }
+        
+        [global::System.Configuration.UserScopedSettingAttribute()]
+        [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+        [global::System.Configuration.DefaultSettingValueAttribute("")]
+        public string ISFScheme {
+            get {
+                return ((string)(this["ISFScheme"]));
+            }
+            set {
+                this["ISFScheme"] = value;
+            }
+        }
     }
 }
diff --git a/ArcFormats/Properties/Settings.settings b/ArcFormats/Properties/Settings.settings
index eaf3d888..0685eef3 100644
--- a/ArcFormats/Properties/Settings.settings
+++ b/ArcFormats/Properties/Settings.settings
@@ -89,5 +89,8 @@
     <Setting Name="MBLPassPhrase" Type="System.String" Scope="User">
       <Value Profile="(Default)" />
     </Setting>
+    <Setting Name="ISFScheme" Type="System.String" Scope="User">
+      <Value Profile="(Default)" />
+    </Setting>
   </Settings>
 </SettingsFile>
\ No newline at end of file
diff --git a/ArcFormats/Strings/arcStrings.Designer.cs b/ArcFormats/Strings/arcStrings.Designer.cs
index 244899de..9eb86aaf 100644
--- a/ArcFormats/Strings/arcStrings.Designer.cs
+++ b/ArcFormats/Strings/arcStrings.Designer.cs
@@ -225,6 +225,15 @@ namespace GameRes.Formats.Strings {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Ignore encryption.
+        /// </summary>
+        public static string ISFIgnoreEncryption {
+            get {
+                return ResourceManager.GetString("ISFIgnoreEncryption", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Default.
         /// </summary>
@@ -280,7 +289,8 @@ namespace GameRes.Formats.Strings {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Archive contains encrypted scripts.Choose encryption scheme or enter a passphrase..
+        ///   Looks up a localized string similar to Archive contains encrypted scripts.
+        ///Choose encryption scheme or enter a passphrase..
         /// </summary>
         public static string MBLNotice {
             get {
diff --git a/ArcFormats/Strings/arcStrings.resx b/ArcFormats/Strings/arcStrings.resx
index 75b2b4b9..37bd7fe5 100644
--- a/ArcFormats/Strings/arcStrings.resx
+++ b/ArcFormats/Strings/arcStrings.resx
@@ -319,7 +319,10 @@ Enter archive encryption key.</value>
     <value>Default</value>
   </data>
   <data name="MBLNotice" xml:space="preserve">
-      <value>Archive contains encrypted scripts.
+    <value>Archive contains encrypted scripts.
 Choose encryption scheme or enter a passphrase.</value>
   </data>
-</root>
+  <data name="ISFIgnoreEncryption" xml:space="preserve">
+    <value>Ignore encryption</value>
+  </data>
+</root>
\ No newline at end of file
diff --git a/ArcFormats/Strings/arcStrings.ru-RU.resx b/ArcFormats/Strings/arcStrings.ru-RU.resx
index 02393dd6..a2e1cf0d 100644
--- a/ArcFormats/Strings/arcStrings.ru-RU.resx
+++ b/ArcFormats/Strings/arcStrings.ru-RU.resx
@@ -162,6 +162,9 @@
 Введите ключ шифрования или выберите
 один из предопределённых вариантов.</value>
   </data>
+  <data name="ISFIgnoreEncryption" xml:space="preserve">
+    <value>Игнорировать шифрование</value>
+  </data>
   <data name="KCAPDefault" xml:space="preserve">
     <value>Неизвестно</value>
   </data>
diff --git a/ArcFormats/WidgetISF.xaml b/ArcFormats/WidgetISF.xaml
new file mode 100644
index 00000000..477dcc2d
--- /dev/null
+++ b/ArcFormats/WidgetISF.xaml
@@ -0,0 +1,10 @@
+<StackPanel x:Class="GameRes.Formats.GUI.WidgetISF"
+            xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+            xmlns:fmt="clr-namespace:GameRes.Formats.DRS"
+            xmlns:p="clr-namespace:GameRes.Formats.Properties"
+            Orientation="Vertical" MaxWidth="250">
+    <ComboBox Name="Scheme" ItemsSource="{Binding Source={x:Static fmt:MpxOpener.KnownSecrets}, Path=Keys, Mode=OneWay}"
+              SelectedValue="{Binding Source={x:Static p:Settings.Default}, Path=ISFScheme, Mode=TwoWay}"
+              Width="200" Grid.Row="0"/>
+</StackPanel>
diff --git a/ArcFormats/WidgetISF.xaml.cs b/ArcFormats/WidgetISF.xaml.cs
new file mode 100644
index 00000000..10abee2e
--- /dev/null
+++ b/ArcFormats/WidgetISF.xaml.cs
@@ -0,0 +1,17 @@
+using System.Windows.Controls;
+
+namespace GameRes.Formats.GUI
+{
+    /// <summary>
+    /// Interaction logic for WidgetISF.xaml
+    /// </summary>
+    public partial class WidgetISF : StackPanel
+    {
+        public WidgetISF ()
+        {
+            InitializeComponent ();
+            if (-1 == Scheme.SelectedIndex)
+                Scheme.SelectedIndex = 0;
+        }
+    }
+}
\ No newline at end of file
diff --git a/ArcFormats/app.config b/ArcFormats/app.config
index dddbbe5b..5944f914 100644
--- a/ArcFormats/app.config
+++ b/ArcFormats/app.config
@@ -91,6 +91,9 @@
             <setting name="MBLPassPhrase" serializeAs="String">
                 <value />
             </setting>
+            <setting name="ISFScheme" serializeAs="String">
+                <value />
+            </setting>
         </GameRes.Formats.Properties.Settings>
     </userSettings>
 <startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup></configuration>