diff --git a/TwlBkpCheck/Windows/TWLBackupBlock/HeaderBody.cs b/TwlBkpCheck/Windows/TWLBackupBlock/HeaderBody.cs
index 9a9336a..e95b1ce 100644
--- a/TwlBkpCheck/Windows/TWLBackupBlock/HeaderBody.cs
+++ b/TwlBkpCheck/Windows/TWLBackupBlock/HeaderBody.cs
@@ -23,6 +23,10 @@ namespace TwlBackupBlock
         // for WithPrivateSave
         public const int RESERVED_SIZE_FOR_WPS = 12;
 
+        // for Legacy
+        public const int RESERVED_SIZE_FOR_LEGACY = 4;
+        public const int NUM_OF_SECTION_LEGACY = 4;
+
         public UInt32 signature;
         public UInt16 companyCode;
         public UInt16 version;
@@ -41,6 +45,10 @@ namespace TwlBackupBlock
         public UInt32 privateSaveForWPS;
         public readonly Byte[] reservedForWPS;
 
+        // for Legacy
+        public UInt32 contentIdForLegacy;
+        public UInt16 contentIndexForLegacy;
+
         private BkpType type;
         private int headerSize;
 
@@ -72,12 +80,19 @@ namespace TwlBackupBlock
 
             uniqueId = new Byte[UNIQUE_ID_SIZE];
             hardwareId = new Byte[HARDWARE_ID_SIZE];
-            fileSizes = new UInt32[NUM_OF_SECTION];
-            contentId = new UInt32[MAX_CONTENTS];
-            contentIndex = new UInt16[MAX_CONTENTS];
+            if (type != BkpType.LEGACY)
+            {
+                fileSizes = new UInt32[NUM_OF_SECTION];
+                contentId = new UInt32[MAX_CONTENTS];
+                contentIndex = new UInt16[MAX_CONTENTS];
+                reserved = new Byte[RESERVED_SIZE];
+            }
+            else
+            {
+                fileSizes = new UInt32[NUM_OF_SECTION_LEGACY];
+                reserved = new Byte[RESERVED_SIZE_FOR_LEGACY];
+            }
             tmdReserved = new TmdReserved();
-            reserved = new Byte[RESERVED_SIZE];
-
             if (type == BkpType.WITH_PRIVATE_SAVE)
             {
                 reservedForWPS = new Byte[RESERVED_SIZE_FOR_WPS];
@@ -154,7 +169,6 @@ namespace TwlBackupBlock
             using (var ms = new MemoryStream(bytes))
             using (var bw = new BinaryWriter(ms))
             {
-                // TODO : Legacy 対応
                 bw.Write(signature);
                 bw.Write(companyCode);
                 bw.Write(version);
@@ -166,16 +180,33 @@ namespace TwlBackupBlock
                 {
                     bw.Write(e);
                 }
-                foreach (UInt32 e in contentId)
+                if (type != BkpType.LEGACY)
                 {
-                    bw.Write(e);
+                    foreach (UInt32 e in contentId)
+                    {
+                        bw.Write(e);
+                    }
                 }
-                foreach (UInt16 e in contentIndex)
+                else
                 {
-                    bw.Write(e);
+                    bw.Write(contentIdForLegacy);
+                }
+                if (type != BkpType.LEGACY)
+                {
+                    foreach (UInt16 e in contentIndex)
+                    {
+                        bw.Write(e);
+                    }
                 }
                 bw.Write(tmdReserved.GetBytes());
-                bw.Write(headerVersion);
+                if (type == BkpType.LEGACY)
+                {
+                    bw.Write(contentIndexForLegacy);
+                }
+                if (type != BkpType.LEGACY)
+                {
+                    bw.Write(headerVersion);
+                }
                 bw.Write(reserved);
                 if (type == BkpType.WITH_PRIVATE_SAVE)
                 {
@@ -204,7 +235,6 @@ namespace TwlBackupBlock
             using (var ms = new MemoryStream(bytes))
             using (var br = new ExtBinaryReader(ms))
             {
-                // TODO : Legacy 対応
                 br.Read(ref signature);
                 br.Read(ref companyCode);
                 br.Read(ref version);
@@ -213,14 +243,31 @@ namespace TwlBackupBlock
                 br.Read(ref titleId);
                 br.Read(ref requiredSize);
                 br.Read(fileSizes);
-                br.Read(contentId);
-                br.Read(contentIndex);
+                if (type != BkpType.LEGACY)
+                {
+                    br.Read(contentId);
+                }
+                else
+                {
+                    br.Read(ref contentIdForLegacy);
+                }
+                if (type != BkpType.LEGACY)
+                {
+                    br.Read(contentIndex);
+                }
                 {
                     byte[] tmdReservedBytes = new byte[TMD_RESERVED_SIZE];
                     br.Read(tmdReservedBytes);
                     tmdReserved.SetBytes(tmdReservedBytes);
                 }
-                br.Read(ref headerVersion);
+                if (type == BkpType.LEGACY)
+                {
+                    br.Read(ref contentIndexForLegacy);
+                }
+                if (type != BkpType.LEGACY)
+                {
+                    br.Read(ref headerVersion);
+                }
                 br.Read(reserved);
                 if (type == BkpType.WITH_PRIVATE_SAVE)
                 {
diff --git a/TwlBkpCheck/Windows/TWLBackupBlock/Utility.cs b/TwlBkpCheck/Windows/TWLBackupBlock/Utility.cs
index c5e97d6..003d59f 100644
--- a/TwlBkpCheck/Windows/TWLBackupBlock/Utility.cs
+++ b/TwlBkpCheck/Windows/TWLBackupBlock/Utility.cs
@@ -23,6 +23,17 @@ namespace TwlBackupBlock
             PRIVATE_SAVE
         };
 
+        // いまいち・・・
+        public const int MAX_CONTENTS_LEGACY = 1;
+        public enum SectionIndexLegacy
+        {
+            TMD,
+            CONTENT,
+            PUBLIC_SAVE = CONTENT + MAX_CONTENTS_LEGACY,
+            SUB_BANNER,
+            PRIVATE_SAVE
+        };
+
         private const int KEY_SIZE = 16;
         private const int ROUND_SCALE = 16;
 
@@ -41,8 +52,10 @@ namespace TwlBackupBlock
         private const int ENCRYPT_BANNER_SIZE = BANNER_SIZE + AES_SIGN_HEADER_SIZE;
         private const int ENCRYPT_HEADER_SIZE = HEADER_SIZE + AES_SIGN_HEADER_SIZE;
         private const int ENCRYPT_EX_HEADER_SIZE = EX_HEADER_SIZE + AES_SIGN_HEADER_SIZE;
+        private const int ENCRYPT_LEGACY_HEADER_SIZE = LEGACY_HEADER_SIZE + AES_SIGN_HEADER_SIZE;
         private const int ENCRYPT_SIGNATURE_SIZE = SIGNATURE_SIZE + AES_SIGN_HEADER_SIZE;
         private const int ENCRYPT_EX_SIGNATURE_SIZE = EX_SIGNATURE_SIZE + AES_SIGN_HEADER_SIZE;
+        private const int ENCRYPT_LEGACY_SIGNATURE_SIZE = LEGACY_SIGNATURE_SIZE + AES_SIGN_HEADER_SIZE;
 
         /// <summary>
         /// バックアップデータをブロックに分割して復号化をおこないます。
@@ -53,17 +66,13 @@ namespace TwlBackupBlock
         /// <returns>分割、復号化されたブロック。</returns>
         public static Blocks DecryptBackupData(byte[] data, byte[] key, BkpType type)
         {
-            // TODO : Legacy 対応
-            if (type == BkpType.LEGACY)
-            {
-                Console.WriteLine("Legacy には未対応です。");
-                return null;
-            }
-
             int headerSize = 0;
             int signatureSize = 0;
             int encryptHeaderSize = 0;
             int encryptSignatureSize = 0;
+            int contentsNum = MAX_CONTENTS;
+            int indexPublicSave = (int)SectionIndexLegacy.PUBLIC_SAVE;
+            int indexSubBanner = (int)SectionIndexLegacy.SUB_BANNER;
 
             switch (type)
             {
@@ -80,6 +89,16 @@ namespace TwlBackupBlock
                     encryptHeaderSize = ENCRYPT_EX_HEADER_SIZE;
                     encryptSignatureSize = ENCRYPT_EX_SIGNATURE_SIZE;
                     break;
+
+                case BkpType.LEGACY:
+                    headerSize = LEGACY_HEADER_SIZE;
+                    signatureSize = LEGACY_SIGNATURE_SIZE;
+                    encryptHeaderSize = ENCRYPT_LEGACY_HEADER_SIZE;
+                    encryptSignatureSize = ENCRYPT_LEGACY_SIGNATURE_SIZE;
+                    contentsNum = MAX_CONTENTS_LEGACY;
+                    indexPublicSave = (int)SectionIndexLegacy.PUBLIC_SAVE;
+                    indexSubBanner = (int)SectionIndexLegacy.SUB_BANNER;
+                    break;
             }
 
             if (data == null)
@@ -122,15 +141,14 @@ namespace TwlBackupBlock
                 blocks.signature.body = new SignatureBody(
                     DecryptBlock(br, signatureSize, key, out blocks.signature.mac, out blocks.signature.iv), type);
 
-                // TODO : Legacy 対応
                 int TMD_SIZE = (int)headerBody.fileSizes[(int)SectionIndex.TMD];
-                int[] CONTENT_SIZE = new int[MAX_CONTENTS];
-                for (int i = 0; i < MAX_CONTENTS; i++)
+                int[] CONTENT_SIZE = new int[contentsNum];
+                for (int i = 0; i < contentsNum; i++)
                 {
                     CONTENT_SIZE[i] = (int)headerBody.fileSizes[(int)SectionIndex.CONTENT + i];
                 }
-                int PUBLIC_SAVE_SIZE = (int)headerBody.fileSizes[(int)SectionIndex.PUBLIC_SAVE];
-                int SUB_BANNER_SIZE = (int)headerBody.fileSizes[(int)SectionIndex.SUB_BANNER];
+                int PUBLIC_SAVE_SIZE = (int)headerBody.fileSizes[indexPublicSave];
+                int SUB_BANNER_SIZE = (int)headerBody.fileSizes[indexSubBanner];
                 int PRIVATE_SAVE_SIZE = 0;
                 if (type == BkpType.WITH_PRIVATE_SAVE)
                 {
@@ -138,7 +156,7 @@ namespace TwlBackupBlock
                 }
 
                 blocks.tmd.body = new Body(DecryptBlock(br, TMD_SIZE, key, out blocks.tmd.mac, out blocks.tmd.iv));
-                for (int i = 0; i < MAX_CONTENTS; i++)
+                for (int i = 0; i < contentsNum; i++)
                 {
                     if (CONTENT_SIZE[i] > 0)
                     {
@@ -393,17 +411,13 @@ namespace TwlBackupBlock
         /// <returns>検証に成功した場合はtrue。それ以外の場合はfalse。</returns>
         public static bool Verify(byte[] data, byte[] aesCbcKey, byte[] aesCmacKey, BkpType type)
         {
-            // TODO : Legacy 対応
-            if (type == BkpType.LEGACY)
-            {
-                Console.WriteLine("Legacy には未対応です。");
-                return false;
-            }
-
             int headerSize = 0;
             int signatureSize = 0;
             int encryptHeaderSize = 0;
             int encryptSignatureSize = 0;
+            int contentsNum = MAX_CONTENTS;
+            int indexPublicSave = (int)SectionIndex.PUBLIC_SAVE;
+            int indexSubBanner = (int)SectionIndex.SUB_BANNER;
 
             switch (type)
             {
@@ -420,6 +434,16 @@ namespace TwlBackupBlock
                     encryptHeaderSize = ENCRYPT_EX_HEADER_SIZE;
                     encryptSignatureSize = ENCRYPT_EX_SIGNATURE_SIZE;
                     break;
+
+                case BkpType.LEGACY:
+                    headerSize = LEGACY_HEADER_SIZE;
+                    signatureSize = LEGACY_SIGNATURE_SIZE;
+                    encryptHeaderSize = ENCRYPT_LEGACY_HEADER_SIZE;
+                    encryptSignatureSize = ENCRYPT_LEGACY_SIGNATURE_SIZE;
+                    contentsNum = MAX_CONTENTS_LEGACY;
+                    indexPublicSave = (int)SectionIndexLegacy.PUBLIC_SAVE;
+                    indexSubBanner = (int)SectionIndexLegacy.SUB_BANNER;
+                    break;
             }
 
             if (data == null)
@@ -492,13 +516,13 @@ namespace TwlBackupBlock
 
                 // TODO : Legacy 対応
                 int TMD_SIZE = (int)headerBody.fileSizes[(int)SectionIndex.TMD];
-                int[] CONTENT_SIZE = new int[MAX_CONTENTS];
-                for (int i = 0; i < MAX_CONTENTS; i++)
+                int[] CONTENT_SIZE = new int[contentsNum];
+                for (int i = 0; i < contentsNum; i++)
                 {
                     CONTENT_SIZE[i] = (int)headerBody.fileSizes[(int)SectionIndex.CONTENT + i];
                 }
-                int PUBLIC_SAVE_SIZE = (int)headerBody.fileSizes[(int)SectionIndex.PUBLIC_SAVE];
-                int SUB_BANNER_SIZE = (int)headerBody.fileSizes[(int)SectionIndex.SUB_BANNER];
+                int PUBLIC_SAVE_SIZE = (int)headerBody.fileSizes[indexPublicSave];
+                int SUB_BANNER_SIZE = (int)headerBody.fileSizes[indexSubBanner];
                 int PRIVATE_SAVE_SIZE = 0;
                 if (type == BkpType.WITH_PRIVATE_SAVE)
                 {
@@ -508,7 +532,7 @@ namespace TwlBackupBlock
                 int restSize = RoundUp(TMD_SIZE, ROUND_SCALE) +
                     RoundUp(PUBLIC_SAVE_SIZE, ROUND_SCALE) + RoundUp(SUB_BANNER_SIZE, ROUND_SCALE) +
                     AES_SIGN_HEADER_SIZE * 3;
-                for (int i = 0; i < MAX_CONTENTS; i++)
+                for (int i = 0; i < contentsNum; i++)
                 {
                     if (CONTENT_SIZE[i] > 0)
                     {
@@ -536,7 +560,7 @@ namespace TwlBackupBlock
                     Console.WriteLine("TMDブロックのハッシュが一致しません");
                     return false;
                 }
-                for (int i = 0; i < MAX_CONTENTS; i++)
+                for (int i = 0; i < contentsNum; i++)
                 {
                     if (CONTENT_SIZE[i] > 0)
                     {
@@ -560,7 +584,7 @@ namespace TwlBackupBlock
                     Console.WriteLine("publicセーブデータブロックのMACが一致しません");
                     return false;
                 }
-                if (!CheckHash(blocks.publicSave, signatureBody.digest.section[(int)SectionIndex.PUBLIC_SAVE]))
+                if (!CheckHash(blocks.publicSave, signatureBody.digest.section[indexPublicSave]))
                 {
                     Console.WriteLine("publicセーブデータブロックのハッシュが一致しません");
                     return false;
@@ -571,7 +595,7 @@ namespace TwlBackupBlock
                     Console.WriteLine("サブバナーブロックの内容とMACが一致しません");
                     return false;
                 }
-                if (!CheckHash(blocks.subBanner, signatureBody.digest.section[(int)SectionIndex.SUB_BANNER]))
+                if (!CheckHash(blocks.subBanner, signatureBody.digest.section[indexSubBanner]))
                 {
                     Console.WriteLine("サブバナーブロックのハッシュが一致しません");
                     return false;