diff --git a/NFC/Cards/NXP MIFARE DESFire/NXP_MIFARE_DESFire.cs b/NFC/Cards/NXP MIFARE DESFire/NXP_MIFARE_DESFire.cs
index c45af86..8696ca2 100644
--- a/NFC/Cards/NXP MIFARE DESFire/NXP_MIFARE_DESFire.cs	
+++ b/NFC/Cards/NXP MIFARE DESFire/NXP_MIFARE_DESFire.cs	
@@ -12,6 +12,7 @@ using Org.BouncyCastle.Crypto.Parameters;
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Security.Cryptography;
 
 namespace NFC.Cards.NXP_MIFARE_DESFire
 {
@@ -305,9 +306,9 @@ namespace NFC.Cards.NXP_MIFARE_DESFire
 
             if (rndA == null)
             {
-                Random rnd = new Random();
                 rndA = new byte[8];
-                rnd.NextBytes(rndA);
+                RNGCryptoServiceProvider cryptoProvider = new RNGCryptoServiceProvider();
+                cryptoProvider.GetBytes(rndA);
             }
             _Log.DebugFormat("rndA: {0}", HexConverter.ConvertToHexString(rndA));
 
@@ -458,9 +459,9 @@ namespace NFC.Cards.NXP_MIFARE_DESFire
 
             if (rndA == null)
             {
-                Random rnd = new Random();
                 rndA = new byte[16];
-                rnd.NextBytes(rndA);
+                RNGCryptoServiceProvider cryptoProvider = new RNGCryptoServiceProvider();
+                cryptoProvider.GetBytes(rndA);
             }
             _Log.DebugFormat("rndA: {0}", HexConverter.ConvertToHexString(rndA));