Encryption/Decryption Issue in Android Device in Unity3d

I am trying to encrypt/decrypt my game score. its working fine as it shoud in Unity Editor. But after build on android device its not working.

Its throwing an error in LogCat, screenshot below

Here is the Scrips I used:

using UnityEngine;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.Security.Cryptography;

public class TripleDESEncryptor : MonoBehaviour {

    private static string encryptionKey = DataEncryptor.Encrypt("@!#$%6+_|:><{}-=)!:%(#+&*><|");

    public static string Encrypt(string toEncrypt, bool useHash){
        if (string.IsNullOrEmpty(encryptionKey))
            return "";

        byte[] keyArray;
        byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

        if(useHash){
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(encryptionKey));
            hashmd5.Clear();
        }else
            keyArray = UTF8Encoding.UTF8.GetBytes(encryptionKey);

        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = keyArray;
        tdes.Mode = CipherMode.ECB;
        tdes.Padding = PaddingMode.PKCS7;

        ICryptoTransform ctransform = tdes.CreateEncryptor();
        byte[] resultArray = ctransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);
        tdes.Clear();

        return Convert.ToBase64String(resultArray, 0, resultArray.Length);

    }

    public static string Decrypt(string cipherString, bool useHash){
        if (string.IsNullOrEmpty(encryptionKey))
            return "";

        byte[] keyArray;
        byte[] toDecryptArray = Convert.FromBase64String(cipherString.Replace(' ', '+'));

        if(useHash){
            MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
            keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(encryptionKey));
            hashmd5.Clear();
        }else 
            keyArray = UTF8Encoding.UTF8.GetBytes(encryptionKey);

        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = keyArray;
        tdes.Mode = CipherMode.ECB;
        tdes.Padding = PaddingMode.PKCS7;

        ICryptoTransform cTransform = tdes.CreateDecryptor();
        byte[] resultArray = cTransform.TransformFinalBlock(toDecryptArray, 0, toDecryptArray.Length);

        return UTF8Encoding.UTF8.GetString(resultArray);

    }
}

And the other script i use for decryption is below:

using UnityEngine;
using System.Collections;
using System.Security.Cryptography;
using System.IO;
using System.Text;
using System.Globalization;

public class DataEncryptor : MonoBehaviour {

    private static string k1_1 = "@!#$%6+_|:><";
    private static string k2_1 = "@!#$%6+_|:><{}-=)!:%(#+&*><|";

    protected static DataEncryptor instance;


    // Use this for initialization
    void Start () {
        if(instance != null){
            Destroy(gameObject);
            return;
        }

        instance = this;
        transform.parent = null;
        DontDestroyOnLoad(gameObject);

    }

    // Update is called once per frame
    void Update () {

    }


    public static string Encrypt(string data){
        //Debug.Log("Data "+data);
        if(string.IsNullOrEmpty(data)){
            return "";
        }
        Rijndael aes = Rijndael.Create();
        aes.Padding = PaddingMode.PKCS7;
        aes.IV = Encoding.ASCII.GetBytes(k1_1);
        aes.Key = Encoding.ASCII.GetBytes(k2_1);

        byte[] rawData = Encoding.Unicode.GetBytes(data);
        MemoryStream memoryStream = new MemoryStream();
        CryptoStream cryptoStream = new CryptoStream(memoryStream, aes.CreateEncryptor(), CryptoStreamMode.Write);

        cryptoStream.Write (rawData, 0, rawData.Length);
        cryptoStream.FlushFinalBlock();
        cryptoStream.Close();

        byte[] encrypted =  memoryStream.ToArray();
        memoryStream.Close();

        return System.Convert.ToBase64String(encrypted);
    }

    public static string Decrypt(string data){
        if(string.IsNullOrEmpty(data)){
            return "";
        }

        byte[] rawData = System.Convert.FromBase64String(data);
        if(rawData.Length < 8){
            Debug.Log("Exception");
            throw new System.ArgumentException("Invalid Input data");
        }

        Rijndael aes = Rijndael.Create();
        aes.Padding = PaddingMode.PKCS7;
        aes.IV = Encoding.ASCII.GetBytes(k1_1);
        aes.Key = Encoding.ASCII.GetBytes(k2_1);

        MemoryStream memoryStream = new MemoryStream();
        CryptoStream cryptoStream = new CryptoStream(memoryStream, aes.CreateDecryptor(), CryptoStreamMode.Write);
        cryptoStream.Write(rawData, 0, rawData.Length);
        cryptoStream.FlushFinalBlock();
        cryptoStream.Close();

        byte[] decrypted = memoryStream.ToArray();
        memoryStream.Close();

        return Encoding.Unicode.GetString(decrypted);
    } 

}

I am saving and encrypting score on OnTriggerEnter like

encryptedScore = TripleDESEncryptor.Encrypt(CoinDetection.currentScore.ToString(), true);
Debug.Log(encryptedScore);

These all are working fine as it should in Unity Editor but not in android device (Didnot checked in iOS). Why? I am hitting my head since 4 days. Please help. Thanks.

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