diff --git a/src/LibHac/Fs/ExternalKeys.cs b/src/LibHac/Fs/ExternalKeys.cs
new file mode 100644
index 00000000..8ee8b883
--- /dev/null
+++ b/src/LibHac/Fs/ExternalKeys.cs
@@ -0,0 +1,38 @@
+using LibHac.FsService;
+using LibHac.Ncm;
+using LibHac.Spl;
+
+namespace LibHac.Fs
+{
+    public static class ExternalKeys
+    {
+        public static Result GetRightsId(this FileSystemClient fs, out RightsId rightsId, TitleId programId,
+            StorageId storageId)
+        {
+            IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
+
+            return fsProxy.GetRightsId(out rightsId, programId, storageId);
+        }
+
+        public static Result RegisterExternalKey(this FileSystemClient fs, ref RightsId rightsId, ref AccessKey key)
+        {
+            IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
+
+            return fsProxy.RegisterExternalKey(ref rightsId, ref key);
+        }
+
+        public static Result UnregisterExternalKey(this FileSystemClient fs, ref RightsId rightsId)
+        {
+            IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
+
+            return fsProxy.UnregisterExternalKey(ref rightsId);
+        }
+
+        public static Result UnregisterAllExternalKey(this FileSystemClient fs)
+        {
+            IFileSystemProxy fsProxy = fs.GetFileSystemProxyServiceObject();
+
+            return fsProxy.UnregisterAllExternalKey();
+        }
+    }
+}
diff --git a/src/LibHac/FsService/FileSystemProxy.cs b/src/LibHac/FsService/FileSystemProxy.cs
index f6c4a0d6..adc67c3c 100644
--- a/src/LibHac/FsService/FileSystemProxy.cs
+++ b/src/LibHac/FsService/FileSystemProxy.cs
@@ -451,18 +451,25 @@ namespace LibHac.FsService
 
         public Result RegisterExternalKey(ref RightsId rightsId, ref AccessKey externalKey)
         {
-            throw new NotImplementedException();
+            // Missing permission check
+
+            return FsProxyCore.RegisterExternalKey(ref rightsId, ref externalKey);
         }
 
         public Result UnregisterExternalKey(ref RightsId rightsId)
         {
-            throw new NotImplementedException();
+            // Missing permission check
+
+            return FsProxyCore.UnregisterExternalKey(ref rightsId);
         }
 
         public Result UnregisterAllExternalKey()
         {
-            throw new NotImplementedException();
+            // Missing permission check
+
+            return FsProxyCore.UnregisterAllExternalKey();
         }
+
         public Result SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed)
         {
             // todo: use struct instead of byte span
diff --git a/src/LibHac/FsService/FileSystemProxyCore.cs b/src/LibHac/FsService/FileSystemProxyCore.cs
index b3df317f..8bda0eaf 100644
--- a/src/LibHac/FsService/FileSystemProxyCore.cs
+++ b/src/LibHac/FsService/FileSystemProxyCore.cs
@@ -3,12 +3,14 @@ using LibHac.Fs;
 using LibHac.FsSystem;
 using LibHac.FsSystem.Save;
 using LibHac.FsService.Creators;
+using LibHac.Spl;
 
 namespace LibHac.FsService
 {
     public class FileSystemProxyCore
     {
         private FileSystemCreators FsCreators { get; }
+        private ExternalKeySet ExternalKeys { get; }
         private byte[] SdEncryptionSeed { get; } = new byte[0x10];
 
         private const string NintendoDirectoryName = "Nintendo";
@@ -16,9 +18,10 @@ namespace LibHac.FsService
 
         private GlobalAccessLogMode LogMode { get; set; }
 
-        public FileSystemProxyCore(FileSystemCreators fsCreators)
+        public FileSystemProxyCore(FileSystemCreators fsCreators, ExternalKeySet externalKeys)
         {
             FsCreators = fsCreators;
+            ExternalKeys = externalKeys ?? new ExternalKeySet();
         }
 
         public Result OpenBisFileSystem(out IFileSystem fileSystem, string rootPath, BisPartitionId partitionId)
@@ -122,6 +125,25 @@ namespace LibHac.FsService
             }
         }
 
+        public Result RegisterExternalKey(ref RightsId rightsId, ref AccessKey externalKey)
+        {
+            return ExternalKeys.Add(rightsId, externalKey);
+        }
+
+        public Result UnregisterExternalKey(ref RightsId rightsId)
+        {
+            ExternalKeys.Remove(rightsId);
+
+            return Result.Success;
+        }
+
+        public Result UnregisterAllExternalKey()
+        {
+            ExternalKeys.Clear();
+
+            return Result.Success;
+        }
+
         public Result SetSdCardEncryptionSeed(ReadOnlySpan<byte> seed)
         {
             seed.CopyTo(SdEncryptionSeed);
diff --git a/src/LibHac/FsService/FileSystemServer.cs b/src/LibHac/FsService/FileSystemServer.cs
index 09d17f40..7e6338c0 100644
--- a/src/LibHac/FsService/FileSystemServer.cs
+++ b/src/LibHac/FsService/FileSystemServer.cs
@@ -15,16 +15,17 @@ namespace LibHac.FsService
         /// Creates a new <see cref="FileSystemServer"/> with a new default <see cref="ITimeSpanGenerator"/>.
         /// </summary>
         /// <param name="fsCreators">The <see cref="FileSystemCreators"/> used for creating filesystems.</param>
-        public FileSystemServer(FileSystemCreators fsCreators) : this(fsCreators, new StopWatchTimeSpanGenerator()) { }
+        public FileSystemServer(FileSystemCreators fsCreators) : this(fsCreators, null, new StopWatchTimeSpanGenerator()) { }
 
         /// <summary>
         /// Creates a new <see cref="FileSystemServer"/>.
         /// </summary>
         /// <param name="fsCreators">The <see cref="FileSystemCreators"/> used for creating filesystems.</param>
+        /// <param name="externalKeys">A keyset containing rights IDs and title keys. If null, an empty set will be created.</param>
         /// <param name="timer">The <see cref="ITimeSpanGenerator"/> to use for access log timestamps.</param>
-        public FileSystemServer(FileSystemCreators fsCreators, ITimeSpanGenerator timer)
+        public FileSystemServer(FileSystemCreators fsCreators, ExternalKeySet externalKeys, ITimeSpanGenerator timer)
         {
-            FsProxyCore = new FileSystemProxyCore(fsCreators);
+            FsProxyCore = new FileSystemProxyCore(fsCreators, externalKeys);
             FsClient = new FileSystemClient(this, timer);
             Timer = timer;
         }
diff --git a/src/LibHac/Keyset.cs b/src/LibHac/Keyset.cs
index 7b51d616..15513df2 100644
--- a/src/LibHac/Keyset.cs
+++ b/src/LibHac/Keyset.cs
@@ -382,7 +382,7 @@ namespace LibHac
         }
     }
 
-    public static class ExternalKeys
+    public static class ExternalKeyReader
     {
         private const int TitleKeySize = 0x10;
 
@@ -390,7 +390,7 @@ namespace LibHac
         public static readonly Dictionary<string, KeyValue> UniqueKeyDict;
         public static readonly Dictionary<string, KeyValue> AllKeyDict;
 
-        static ExternalKeys()
+        static ExternalKeyReader()
         {
             List<KeyValue> commonKeys = CreateCommonKeyList();
             List<KeyValue> uniqueKeys = CreateUniqueKeyList();
diff --git a/src/hactoolnet/Program.cs b/src/hactoolnet/Program.cs
index 84ed4fb8..c352c039 100644
--- a/src/hactoolnet/Program.cs
+++ b/src/hactoolnet/Program.cs
@@ -174,7 +174,7 @@ namespace hactoolnet
                 consoleKeyFile = homeConsoleKeyFile;
             }
 
-            ctx.Keyset = ExternalKeys.ReadKeyFile(keyFile, titleKeyFile, consoleKeyFile, ctx.Logger);
+            ctx.Keyset = ExternalKeyReader.ReadKeyFile(keyFile, titleKeyFile, consoleKeyFile, ctx.Logger);
             if (ctx.Options.SdSeed != null)
             {
                 ctx.Keyset.SetSdSeed(ctx.Options.SdSeed.ToBytes());
@@ -185,15 +185,15 @@ namespace hactoolnet
                 string dir = ctx.Options.OutDir;
                 Directory.CreateDirectory(dir);
 
-                File.WriteAllText(Path.Combine(dir, keyFileName), ExternalKeys.PrintCommonKeys(ctx.Keyset));
-                File.WriteAllText(Path.Combine(dir, "console.keys"), ExternalKeys.PrintUniqueKeys(ctx.Keyset));
-                File.WriteAllText(Path.Combine(dir, "title.keys"), ExternalKeys.PrintTitleKeys(ctx.Keyset));
+                File.WriteAllText(Path.Combine(dir, keyFileName), ExternalKeyReader.PrintCommonKeys(ctx.Keyset));
+                File.WriteAllText(Path.Combine(dir, "console.keys"), ExternalKeyReader.PrintUniqueKeys(ctx.Keyset));
+                File.WriteAllText(Path.Combine(dir, "title.keys"), ExternalKeyReader.PrintTitleKeys(ctx.Keyset));
             }
         }
 
         private static void ProcessKeygen(Context ctx)
         {
-            Console.WriteLine(ExternalKeys.PrintCommonKeys(ctx.Keyset));
+            Console.WriteLine(ExternalKeyReader.PrintCommonKeys(ctx.Keyset));
         }
 
         // For running random stuff