diff --git a/de4dot.code/deobfuscators/dotNET_Reactor/v4/EncryptedResource.cs b/de4dot.code/deobfuscators/dotNET_Reactor/v4/EncryptedResource.cs
index b5b8c3d0..2280af5f 100644
--- a/de4dot.code/deobfuscators/dotNET_Reactor/v4/EncryptedResource.cs
+++ b/de4dot.code/deobfuscators/dotNET_Reactor/v4/EncryptedResource.cs
@@ -155,12 +155,7 @@ namespace de4dot.code.deobfuscators.dotNET_Reactor.v4 {
 			if (encryptedDataResource == null || key == null || iv == null)
 				throw new ApplicationException("Can't decrypt resource");
 
-			using (var aes = new RijndaelManaged { Mode = CipherMode.CBC }) {
-				using (var transform = aes.CreateDecryptor(key, iv)) {
-					var encryptedData = encryptedDataResource.GetResourceData();
-					return transform.TransformFinalBlock(encryptedData, 0, encryptedData.Length);
-				}
-			}
+			return DeobUtils.aesDecrypt(encryptedDataResource.GetResourceData(), key, iv);
 		}
 
 		public byte[] encrypt(byte[] data) {
diff --git a/de4dot.code/deobfuscators/dotNET_Reactor/v4/StringDecrypter.cs b/de4dot.code/deobfuscators/dotNET_Reactor/v4/StringDecrypter.cs
index d726548e..0bd3db46 100644
--- a/de4dot.code/deobfuscators/dotNET_Reactor/v4/StringDecrypter.cs
+++ b/de4dot.code/deobfuscators/dotNET_Reactor/v4/StringDecrypter.cs
@@ -20,7 +20,6 @@
 using System;
 using System.Text;
 using System.Collections.Generic;
-using System.Security.Cryptography;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
 using de4dot.blocks;
@@ -249,13 +248,7 @@ namespace de4dot.code.deobfuscators.dotNET_Reactor.v4 {
 				else
 					throw new ApplicationException("Unknown string decrypter version");
 
-				byte[] decryptedStringData;
-				using (var aes = new RijndaelManaged { Mode = CipherMode.CBC }) {
-					using (var transform = aes.CreateDecryptor(info.key, info.iv)) {
-						decryptedStringData = transform.TransformFinalBlock(encryptedStringData, 0, encryptedStringData.Length);
-					}
-				}
-				return Encoding.Unicode.GetString(decryptedStringData);
+				return Encoding.Unicode.GetString(DeobUtils.aesDecrypt(encryptedStringData, info.key, info.iv));
 			}
 		}