[SOLVED] CryptographicException: Invalid input block size AES Decrypt

Hi everybody and thanks by advance for your time

i have a trouble since 2 days with my AES encryp/decrypt
to do this i use Usecurity asset from assetstore.

but the problem is when i send an encrypted text to my database sometimes i get errors

if i send something simple like "hello world how are you today ?" that's work but if i send something stupid like:
"gaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa" i get error
i get error about invalid input block size on unity 5+ and invalid length on unity 2018+

i know the easy way it's to not send something stupid but the apk gonna be used by some people so i prefere to prevent errors .

here is the error code from unity 5+

Code (CSharp):

1. ryptographicException: Invalid input block size.
2. Mono.Security.Cryptography.SymmetricTransform.FinalDecrypt (System.Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/Mono.Security.Cryptography/SymmetricTransform.cs:462)
3. Mono.Security.Cryptography.SymmetricTransform.TransformFinalBlock (System.Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/Mono.Security.Cryptography/SymmetricTransform.cs:554)
4. System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock (System.Byte[] inputBuffer, Int32 inputOffset, Int32 inputCount) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Security.Cryptography/RijndaelManagedTransform.cs:94)
5. System.Security.Cryptography.CryptoStream.Read (System.Byte[] buffer, Int32 offset, Int32 count) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System.Security.Cryptography/CryptoStream.cs:205)
6. Assets.USecurity.AES.Decrypt (System.String value, System.String password) (at Assets/USecurity/AES.cs:70)
7. Body.ShowMessages () (at Assets/CommUnity/Scripts/Body.cs:503)
8. Header.MessagesBtn () (at Assets/CommUnity/Scripts/Header.cs:44)
9. UnityEngine.Events.InvokableCall.Invoke (System.Object[] args) (at C:/buildslave/unity/build/Runtime/Export/UnityEvent.cs:154)
10. UnityEngine.Events.InvokableCallList.Invoke (System.Object[] parameters) (at C:/buildslave/unity/build/Runtime/Export/UnityEvent.cs:637)
11. UnityEngine.Events.UnityEventBase.Invoke (System.Object[] parameters) (at C:/buildslave/unity/build/Runtime/Export/UnityEvent.cs:773)
12. UnityEngine.Events.UnityEvent.Invoke () (at C:/buildslave/unity/build/Runtime/Export/UnityEvent_0.cs:52)
13. UnityEngine.UI.Button.Press () (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:35)
14. UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:44)
15. UnityEngine.EventSystems.ExecuteEvents.Execute (IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:50)
16. UnityEngine.EventSystems.ExecuteEvents.Execute[IPointerClickHandler] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.EventFunction`1 functor) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:261)
17. UnityEngine.EventSystems.EventSystem:Update()
18.  

error code on unity 2018+:

Code (CSharp):

1. FormatException: Invalid length.
2. System.Convert.FromBase64String (System.String s) (at /Users/builduser/buildslave/mono/build/mcs/class/corlib/System/Convert.cs:146)
3. Assets.USecurity.AES.Decrypt (System.String value, System.String password) (at Assets/USecurity/AES.cs:60)
4. Body.ShowMessages () (at Assets/CommUnity/Scripts/Body.cs:503)
5. Header.MessagesBtn () (at Assets/CommUnity/Scripts/Header.cs:44)
6. UnityEngine.Events.InvokableCall.Invoke () (at C:/buildslave/unity/build/Runtime/Export/UnityEvent.cs:166)
7. UnityEngine.Events.UnityEvent.Invoke () (at C:/buildslave/unity/build/Runtime/Export/UnityEvent_0.cs:58)
8. UnityEngine.UI.Button.Press () (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:36)
9. UnityEngine.UI.Button.OnPointerClick (UnityEngine.EventSystems.PointerEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/UI/Core/Button.cs:45)
10. UnityEngine.EventSystems.ExecuteEvents.Execute (IPointerClickHandler handler, UnityEngine.EventSystems.BaseEventData eventData) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:50)
11. UnityEngine.EventSystems.ExecuteEvents.Execute[IPointerClickHandler] (UnityEngine.GameObject target, UnityEngine.EventSystems.BaseEventData eventData, UnityEngine.EventSystems.EventFunction`1 functor) (at C:/buildslave/unity/build/Extensions/guisystem/UnityEngine.UI/EventSystem/ExecuteEvents.cs:261)
12. UnityEngine.EventSystems.EventSystem:Update()

and this is the AES encryption script i use :

Code (CSharp):

1. using System;
2. using System.IO;
3. using System.Security.Cryptography;
4. using System.Text;
5.  
6. namespace Assets.USecurity
7. {
8.     /// <summary>
9.     /// AES (Advanced Encryption Standard) implementation with 128-bit key (default);
10.     /// 128-bit AES is approved  by NIST, but not the 256-bit AES;
11.     /// 256-bit AES is slower than the 128-bit AES (by about 40%);
12.     /// Use it for secure data protection;
13.     /// Do NOT use it for data protection in RAM (in most common scenarios);
14.     /// </summary>
15.     public static class AES
16.     {
17.         /// <summary>
18.         /// Key lenght, 128 (default) or 256.
19.         /// </summary>
20.         public static int KeyLength = 128;
21.         private const string SaltKey = "ShMG8hLyZ7k~Ge5@";
22.         private const string VIKey = "~6YUi0Sv5@|{aOZO"; // TODO: It's strongy recommended to generate random VI each encryption (and store it with encrypted value)
23.  
24.         /// <summary>
25.         /// Encrypt plain string using password.
26.         /// </summary>
27.         public static string Encrypt(string value, string password)
28.         {
29.             return Encrypt(Encoding.UTF8.GetBytes(value), password);
30.         }
31.  
32.         /// <summary>
33.         /// Encrypt plain byte array using password.
34.         /// </summary>
35.         public static string Encrypt(byte[] value, string password)
36.         {
37.             var keyBytes = new Rfc2898DeriveBytes(password, Encoding.UTF8.GetBytes(SaltKey)).GetBytes(KeyLength / 8);
38.             var symmetricKey = new RijndaelManaged { Mode = CipherMode.CBC, Padding = PaddingMode.Zeros };
39.             var encryptor = symmetricKey.CreateEncryptor(keyBytes, Encoding.UTF8.GetBytes(VIKey));
40.  
41.             using (var memoryStream = new MemoryStream())
42.             {
43.                 using (var cryptoStream = new CryptoStream(memoryStream, encryptor, CryptoStreamMode.Write))
44.                 {
45.                     cryptoStream.Write(value, 0, value.Length);
46.                     cryptoStream.FlushFinalBlock();
47.                     cryptoStream.Close();
48.                     memoryStream.Close();
49.  
50.                     return Convert.ToBase64String(memoryStream.ToArray());
51.                 }
52.             }
53.         }
54.  
55.         /// <summary>
56.         /// Decrypt AES-encrypted string using password.
57.         /// </summary>
58.         public static string Decrypt(string value, string password)
59.         {
60.             var cipherTextBytes = Convert.FromBase64String(value);
61.             var keyBytes = new Rfc2898DeriveBytes(password, Encoding.UTF8.GetBytes(SaltKey)).GetBytes(KeyLength / 8);
62.             var symmetricKey = new RijndaelManaged { Mode = CipherMode.CBC, Padding = PaddingMode.None };
63.             var decryptor = symmetricKey.CreateDecryptor(keyBytes, Encoding.UTF8.GetBytes(VIKey));
64.  
65.             using (var memoryStream = new MemoryStream(cipherTextBytes))
66.             {
67.                 using (var cryptoStream = new CryptoStream(memoryStream, decryptor, CryptoStreamMode.Read))
68.                 {
69.                     var plainTextBytes = new byte[cipherTextBytes.Length];
70.                     var decryptedByteCount = cryptoStream.Read(plainTextBytes, 0, plainTextBytes.Length);
71.  
72.                     memoryStream.Close();
73.                     cryptoStream.Close();
74.  
75.                     return Encoding.UTF8.GetString(plainTextBytes, 0, decryptedByteCount).TrimEnd("\0".ToCharArray());
76.                 }
77.             }
78.         }
79.     }
80. }

please help me to solve this , i really dont understand what's the problem.
thanks a lot for your help i really appreciate that .

or maybe check if the length is invalid and send "error message"
because in my apk if i get the error message i can't access to the messaging center anymore

 

i solved it by waiting to receive the encrypted text and after this decrypt the text , it was a conflit because and decrypt it in the same time i received it .

that was the problem

 

I am having same problem but didnt understand a bit from your solution what do you mean by waiting to receive, lease help