diff --git a/src/Libplanet.Action/AssemblyInfo.cs b/src/Libplanet.Action/AssemblyInfo.cs
index 3b64ad1989d..d32db2c362f 100644
--- a/src/Libplanet.Action/AssemblyInfo.cs
+++ b/src/Libplanet.Action/AssemblyInfo.cs
@@ -1,6 +1,7 @@
 using System.Runtime.CompilerServices;
 
-[assembly: InternalsVisibleTo("Libplanet.Tests")]
+[assembly: InternalsVisibleTo("Libplanet")]
 [assembly: InternalsVisibleTo("Libplanet.Action.Tests")]
 [assembly: InternalsVisibleTo("Libplanet.Explorer.Tests")]
 [assembly: InternalsVisibleTo("Libplanet.Mocks")]
+[assembly: InternalsVisibleTo("Libplanet.Tests")]
diff --git a/src/Libplanet/Blockchain/StateStoreExtensions.cs b/src/Libplanet/Blockchain/StateStoreExtensions.cs
new file mode 100644
index 00000000000..333b3d1fdaf
--- /dev/null
+++ b/src/Libplanet/Blockchain/StateStoreExtensions.cs
@@ -0,0 +1,104 @@
+using System;
+using System.Security.Cryptography;
+using Bencodex.Types;
+using Libplanet.Action.State;
+using Libplanet.Common;
+using Libplanet.Crypto;
+using Libplanet.Store.Trie;
+using Libplanet.Types.Blocks;
+
+namespace Libplanet.Store
+{
+    /// <summary>
+    /// Convenient extension methods for <see cref="IStateStore"/>.
+    /// </summary>
+    public static class IStateStoreExtensions
+    {
+        /// <summary>
+        /// Commits <paramref name="data"/> representing a world state directly
+        /// to <see cref="IStateStore"/> and returns its state root hash.
+        /// The world state created is set to <see cref="BlockMetadata.CurrentProtocolVersion"/>.
+        /// </summary>
+        /// <param name="stateStore">The <see cref="IStateStore"/> to commit to.</param>
+        /// <param name="data">The data representing a world state to commit.</param>
+        /// <returns></returns>
+        /// <exception cref="ArgumentException">Thrown if given <paramref name="data"/>
+        /// is not in the right format.
+        /// <list type="bullet">
+        /// <item><description>
+        ///   Every key in <paramref name="data"/> must be a <see cref="Binary"/> of length
+        ///   <see cref="Address.Size"/>.
+        /// </description></item>
+        /// <item><description>
+        ///   Every value in <paramref name="data"/> must be a <see cref="Dictionary"/> with
+        ///   each key in the <see cref="Dictionary"/> being a <see cref="Binary"/> of length
+        ///   <see cref="Address.Size"/>.
+        /// </description></item>
+        /// </list>
+        /// </exception>
+        public static HashDigest<SHA256> CommitWorld(this IStateStore stateStore, Dictionary data)
+        {
+            var stateRoot = stateStore.GetStateRoot(null);
+            stateRoot = stateRoot.SetMetadata(
+                new TrieMetadata(BlockMetadata.CurrentProtocolVersion));
+            foreach((var key, var value) in data)
+            {
+                if (key is not Binary binary)
+                {
+                    throw new ArgumentException(
+                        $"Given {data} contains a key that is of invalid type: {key.GetType()}",
+                        nameof(data));
+                }
+
+                if (binary.ByteArray.Length != Address.Size)
+                {
+                    throw new ArgumentException(
+                        $"Given {data} contains a key that is of invalid length that is " +
+                        $"not {Address.Size}: {binary.ByteArray.Length}",
+                        nameof(data));
+                }
+
+                if (value is not Dictionary dict)
+                {
+                    throw new ArgumentException(
+                        $"Given {data} contains a value that is of invalid type: {value.GetType()}",
+                        nameof(data));
+                }
+
+                stateRoot = stateRoot.Set(
+                    KeyConverters.ToStateKey(new Address(binary.ByteArray)),
+                    new Binary(stateStore.CommitAccount(dict).ByteArray));
+            }
+
+            return stateStore.Commit(stateRoot).Hash;
+        }
+
+        private static HashDigest<SHA256> CommitAccount(this IStateStore stateStore, Dictionary data)
+        {
+            var stateRoot = stateStore.GetStateRoot(null);
+            foreach((var key, var value) in data)
+            {
+                if (key is not Binary binary)
+                {
+                    throw new ArgumentException(
+                        $"Given {data} contains a key that is of invalid type: {key.GetType()}",
+                        nameof(data));
+                }
+
+                if (binary.ByteArray.Length != Address.Size)
+                {
+                    throw new ArgumentException(
+                        $"Given {data} contains a key that is of invalid length that is " +
+                        $"not {Address.Size}: {binary.ByteArray.Length}",
+                        nameof(data));
+                }
+
+                stateRoot = stateRoot.Set(
+                    KeyConverters.ToStateKey(new Address(binary.ByteArray)),
+                    value);
+            }
+
+            return stateStore.Commit(stateRoot).Hash;
+        }
+    }
+}