diff --git a/hactoolnet/Program.cs b/hactoolnet/Program.cs
index afa41a22..726ce303 100644
--- a/hactoolnet/Program.cs
+++ b/hactoolnet/Program.cs
@@ -8,6 +8,12 @@ namespace hactoolnet
     public static class Program
     {
         static void Main(string[] args)
+        {
+            ReadNca();
+            //ListSdfs(args);
+        }
+
+        private static void ListSdfs(string[] args)
         {
             var sdfs = LoadSdFs(args);
 
@@ -18,7 +24,22 @@ namespace hactoolnet
             ListTitles(sdfs);
 
             //DecryptNax0(sdfs, "C0628FB07A89E9050BDA258F74868E8D");
-            DecryptTitle(sdfs, 0x0100000000010800);
+            DecryptTitle(sdfs, 0x010025400AECE000);
+        }
+
+        static void ReadNca()
+        {
+            var keyset = ExternalKeys.ReadKeyFile("keys.txt", "titlekeys.txt");
+            using (var file = new FileStream("acc9da939a8e0b339aa3be3d409d9ada.nca", FileMode.Open, FileAccess.Read))
+            {
+                var nca = new Nca(keyset, file, false);
+                var romfs = nca.OpenSection(0);
+
+                using (var output = new FileStream("romfs_net", FileMode.Create))
+                {
+                    romfs.CopyTo(output);
+                }
+            }
         }
 
         static void DecryptNax0(SdFs sdFs, string name)
diff --git a/libhac/Keyset.cs b/libhac/Keyset.cs
index 99b9ca72..c4a7c54e 100644
--- a/libhac/Keyset.cs
+++ b/libhac/Keyset.cs
@@ -41,6 +41,8 @@ namespace libhac
         public byte[] acid_fixed_key_modulus { get; set; } = new byte[0x100];
         public byte[] package2_fixed_key_modulus { get; set; } = new byte[0x100];
 
+        public Dictionary<byte[], byte[]> TitleKeys { get; } = new Dictionary<byte[], byte[]>(new ByteArray128BitComparer());
+
         public void SetSdSeed(byte[] sdseed)
         {
             for (int k = 0; k < sd_card_key_sources.Length; k++)
@@ -76,12 +78,46 @@ namespace libhac
 
     public static class ExternalKeys
     {
+        private const int TitleKeySize = 0x10;
         private static readonly Dictionary<string, KeyValue> KeyDict = CreateKeyDict();
 
+        public static Keyset ReadKeyFile(string filename, string titleKeysFilename, IProgressReport progress = null)
+        {
+            var keyset = ReadKeyFile(filename, progress);
+            using (var reader = new StreamReader(new FileStream(titleKeysFilename, FileMode.Open, FileAccess.Read)))
+            {
+                string line;
+                while ((line = reader.ReadLine()) != null)
+                {
+                    var a = line.Split(',');
+                    if (a.Length != 2) continue;
+
+                    var rightsId = a[0].Trim().ToBytes();
+                    var titleKey = a[1].Trim().ToBytes();
+
+                    if (rightsId.Length != TitleKeySize)
+                    {
+                        progress?.LogMessage($"Rights ID {rightsId.ToHexString()} had incorrect size {rightsId.Length}. (Expected {TitleKeySize})");
+                        continue;
+                    }
+
+                    if (titleKey.Length != TitleKeySize)
+                    {
+                        progress?.LogMessage($"Title key {titleKey.ToHexString()} had incorrect size {titleKey.Length}. (Expected {TitleKeySize})");
+                        continue;
+                    }
+
+                    keyset.TitleKeys.Add(rightsId, titleKey);
+                }
+            }
+
+            return keyset;
+        }
+
         public static Keyset ReadKeyFile(string filename, IProgressReport progress = null)
         {
             var keyset = new Keyset();
-            using (var reader = new StreamReader(new FileStream(filename, FileMode.Open)))
+            using (var reader = new StreamReader(new FileStream(filename, FileMode.Open, FileAccess.Read)))
             {
                 string line;
                 while ((line = reader.ReadLine()) != null)
diff --git a/libhac/Nca.cs b/libhac/Nca.cs
index 345803e0..14a65c63 100644
--- a/libhac/Nca.cs
+++ b/libhac/Nca.cs
@@ -57,6 +57,8 @@ namespace libhac
                     size = sect.Pfs0.Pfs0Size;
                     break;
                 case SectionFsType.Romfs:
+                    offset = sect.Offset + (long)sect.Header.Romfs.IvfcHeader.LevelHeaders[Romfs.IvfcMaxLevel - 1].LogicalOffset;
+                    size = (long)sect.Header.Romfs.IvfcHeader.LevelHeaders[Romfs.IvfcMaxLevel - 1].HashDataSize;
                     break;
                 default:
                     throw new ArgumentOutOfRangeException();
diff --git a/libhac/Romfs.cs b/libhac/Romfs.cs
new file mode 100644
index 00000000..8d28d5f8
--- /dev/null
+++ b/libhac/Romfs.cs
@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace libhac
+{
+    public class Romfs
+    {
+        public static readonly int IvfcMaxLevel = 6;
+    }
+
+    public class RomfsHeader
+    {
+        public ulong HeaderSize;
+        public ulong DirHashTableOffset;
+        public ulong DirHashTableSize;
+        public ulong DirMetaTableOffset;
+        public ulong DirMetaTableSize;
+        public ulong FileHashTableOffset;
+        public ulong FileHashTableSize;
+        public ulong FileMetaTableOffset;
+        public ulong FileMetaTableSize;
+        public ulong DataOffset;
+    }
+
+    public class IvfcLevel
+    {
+        public ulong DataOffset { get; set; }
+        public ulong DataSize { get; set; }
+        public ulong HashOffset { get; set; }
+        public ulong HashBlockSize { get; set; }
+        public ulong HashBlockCount { get; set; }
+    }
+}
diff --git a/libhac/Util.cs b/libhac/Util.cs
index d0ef138a..86d3c9dc 100644
--- a/libhac/Util.cs
+++ b/libhac/Util.cs
@@ -1,5 +1,7 @@
 using System;
+using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text;
 
 namespace libhac
@@ -255,4 +257,44 @@ namespace libhac
             return readable.ToString("0.### ") + suffix;
         }
     }
+
+    public class ByteArray128BitComparer : EqualityComparer<byte[]>
+    {
+        public override bool Equals(byte[] first, byte[] second)
+        {
+            if (first == null || second == null)
+            {
+                // null == null returns true.
+                // non-null == null returns false.
+                return first == second;
+            }
+            if (ReferenceEquals(first, second))
+            {
+                return true;
+            }
+            if (first.Length != second.Length)
+            {
+                return false;
+            }
+            // Linq extension method is based on IEnumerable, must evaluate every item.
+            return first.SequenceEqual(second);
+        }
+
+        public override int GetHashCode(byte[] obj)
+        {
+            if (obj == null)
+            {
+                throw new ArgumentNullException(nameof(obj));
+            }
+            if (obj.Length != 16)
+            {
+                throw new ArgumentException("Length must be 16 bytes");
+            }
+
+            var hi = BitConverter.ToUInt64(obj, 0);
+            var lo = BitConverter.ToUInt64(obj, 8);
+
+            return (hi.GetHashCode() * 397) ^ lo.GetHashCode();
+        }
+    }
 }