diff --git a/src/neo/IO/Helper.cs b/src/neo/IO/Helper.cs
index e44e5bbe0a..ab8b2ce404 100644
--- a/src/neo/IO/Helper.cs
+++ b/src/neo/IO/Helper.cs
@@ -12,8 +12,6 @@ namespace Neo.IO
 {
     public static class Helper
     {
-        public const int GroupingSizeInBytes = 16;
-
         public static T AsSerializable<T>(this byte[] value, int start = 0) where T : ISerializable, new()
         {
             using (MemoryStream ms = new MemoryStream(value, start, value.Length - start, false))
@@ -144,24 +142,6 @@ public static int GetVarSize(this string value)
             return GetVarSize(size) + size;
         }
 
-        public static byte[] ReadBytesWithGrouping(this BinaryReader reader)
-        {
-            using (MemoryStream ms = new MemoryStream())
-            {
-                int count;
-                do
-                {
-                    byte[] group = reader.ReadFixedBytes(GroupingSizeInBytes);
-                    count = reader.ReadByte();
-                    if (count > GroupingSizeInBytes)
-                        throw new FormatException();
-                    if (count > 0)
-                        ms.Write(group, 0, count);
-                } while (count == GroupingSizeInBytes);
-                return ms.ToArray();
-            }
-        }
-
         public static byte[] ReadFixedBytes(this BinaryReader reader, int size)
         {
             var index = 0;
@@ -277,25 +257,6 @@ public static void Write<T>(this BinaryWriter writer, IReadOnlyCollection<T> val
             }
         }
 
-        public static void WriteBytesWithGrouping(this BinaryWriter writer, byte[] value)
-        {
-            int index = 0;
-            int remain = value.Length;
-            while (remain >= GroupingSizeInBytes)
-            {
-                writer.Write(value, index, GroupingSizeInBytes);
-                writer.Write((byte)GroupingSizeInBytes);
-                index += GroupingSizeInBytes;
-                remain -= GroupingSizeInBytes;
-            }
-            if (remain > 0)
-                writer.Write(value, index, remain);
-            int padding = GroupingSizeInBytes - remain;
-            for (int i = 0; i < padding; i++)
-                writer.Write((byte)0);
-            writer.Write((byte)remain);
-        }
-
         public static void WriteFixedString(this BinaryWriter writer, string value, int length)
         {
             if (value == null)
diff --git a/src/neo/Ledger/StorageKey.cs b/src/neo/Ledger/StorageKey.cs
index af7258f2ce..bf1e3c447b 100644
--- a/src/neo/Ledger/StorageKey.cs
+++ b/src/neo/Ledger/StorageKey.cs
@@ -1,6 +1,7 @@
 using Neo.Cryptography;
 using Neo.IO;
 using System;
+using System.Buffers.Binary;
 using System.IO;
 
 namespace Neo.Ledger
@@ -10,31 +11,22 @@ public class StorageKey : IEquatable<StorageKey>, ISerializable
         public int Id;
         public byte[] Key;
 
-        int ISerializable.Size => sizeof(int) + (Key.Length / 16 + 1) * 17;
+        int ISerializable.Size => sizeof(int) + Key.Length;
 
-        internal static byte[] CreateSearchPrefix(int id, byte[] prefix)
+        internal static byte[] CreateSearchPrefix(int id, ReadOnlySpan<byte> prefix)
         {
-            using (MemoryStream ms = new MemoryStream())
-            {
-                int index = 0;
-                int remain = prefix.Length;
-                while (remain >= 16)
-                {
-                    ms.Write(prefix, index, 16);
-                    ms.WriteByte(16);
-                    index += 16;
-                    remain -= 16;
-                }
-                if (remain > 0)
-                    ms.Write(prefix, index, remain);
-                return Helper.Concat(BitConverter.GetBytes(id), ms.ToArray());
-            }
+            byte[] buffer = new byte[sizeof(int) + prefix.Length];
+            BinaryPrimitives.WriteInt32LittleEndian(buffer, id);
+            prefix.CopyTo(buffer.AsSpan(sizeof(int)));
+            return buffer;
         }
 
+        //If the base stream of the reader doesn't support seeking, a NotSupportedException is thrown.
+        //But StorageKey never works with NetworkStream, so it doesn't matter.
         void ISerializable.Deserialize(BinaryReader reader)
         {
             Id = reader.ReadInt32();
-            Key = reader.ReadBytesWithGrouping();
+            Key = reader.ReadBytes((int)(reader.BaseStream.Length - reader.BaseStream.Position));
         }
 
         public bool Equals(StorageKey other)
@@ -60,7 +52,7 @@ public override int GetHashCode()
         void ISerializable.Serialize(BinaryWriter writer)
         {
             writer.Write(Id);
-            writer.WriteBytesWithGrouping(Key);
+            writer.Write(Key);
         }
     }
 }
diff --git a/tests/neo.UnitTests/IO/UT_IOHelper.cs b/tests/neo.UnitTests/IO/UT_IOHelper.cs
index 3b36695b2d..1128270716 100644
--- a/tests/neo.UnitTests/IO/UT_IOHelper.cs
+++ b/tests/neo.UnitTests/IO/UT_IOHelper.cs
@@ -285,45 +285,6 @@ public void TestGetVarSizeString()
             Assert.AreEqual(3, result);
         }
 
-        [TestMethod]
-        public void TestReadBytesWithGrouping()
-        {
-            for (int i = 0; i < 2; i++)
-            {
-                if (i == 0)
-                {
-                    byte[] caseArray = new byte[] { 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                    0xAA, 0xAA, 0xAA, 0xAA};
-                    MemoryStream stream = new MemoryStream();
-                    BinaryWriter writer = new BinaryWriter(stream);
-                    Neo.IO.Helper.WriteBytesWithGrouping(writer, caseArray);
-                    stream.Seek(0, SeekOrigin.Begin);
-                    BinaryReader reader = new BinaryReader(stream);
-                    byte[] result = Neo.IO.Helper.ReadBytesWithGrouping(reader);
-                    Assert.AreEqual(Encoding.Default.GetString(caseArray), Encoding.Default.GetString(result));
-                }
-                else
-                {
-                    byte[] caseArray = new byte[] { 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,0x10,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,0x10,
-                                                    0xAA, 0xAA, 0xAA, 0xAA, 0x00, 0x00, 0x00, 0x00,
-                                                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,0x11};
-                    MemoryStream stream = new MemoryStream();
-                    BinaryWriter writer = new BinaryWriter(stream);
-                    writer.Write(caseArray);
-                    stream.Seek(0, SeekOrigin.Begin);
-                    BinaryReader reader = new BinaryReader(stream);
-                    Action action = () => Neo.IO.Helper.ReadBytesWithGrouping(reader);
-                    action.Should().Throw<FormatException>();
-                }
-            }
-        }
-
         [TestMethod]
         public void TestReadFixedString()
         {
@@ -474,28 +435,6 @@ public void TestWriteGeneric()
                                                                          0x00,0x00,0x00,0x00,0x00}), Encoding.Default.GetString(byteArray));
         }
 
-
-        [TestMethod]
-        public void TestWriteBytesWithGrouping()
-        {
-            MemoryStream stream = new MemoryStream();
-            BinaryWriter writer = new BinaryWriter(stream);
-            Neo.IO.Helper.WriteBytesWithGrouping(writer, new byte[] { 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                                      0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                                      0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                                      0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                                      0xAA, 0xAA, 0xAA, 0xAA});
-            stream.Seek(0, SeekOrigin.Begin);
-            byte[] byteArray = new byte[stream.Length];
-            stream.Read(byteArray, 0, (int)stream.Length);
-            Assert.AreEqual(Encoding.Default.GetString(new byte[] { 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,0x10,
-                                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,
-                                                                    0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA, 0xAA,0x10,
-                                                                    0xAA, 0xAA, 0xAA, 0xAA, 0x00, 0x00, 0x00, 0x00,
-                                                                    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,0x04}), Encoding.Default.GetString(byteArray));
-        }
-
         [TestMethod]
         public void TestWriteFixedString()
         {