数据加密解密时 出现 “填充无效，无法被移除”错误
当解密数据是报“填充无效，无法被移除”错误 ，加密解密类 如下，求高手解惑！！！

using System;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using Snail.Common.Extensions;

namespace Snail.Common.Security
{
    public class EncryptionService:IEncryptionService
    {
        public byte[] Decode(byte[] encodedData)
        {
            using (var symmetricAlgorithm = CreateSymmetricAlgorithm())
            {
                using (var hashAlgorithm = CreateHashAlgorithm())
                {
                    var iv = new byte[symmetricAlgorithm.BlockSize / 8];
                    var signature = new byte[hashAlgorithm.HashSize / 8];
                    var data = new byte[encodedData.Length - iv.Length - signature.Length];

                    Array.Copy(encodedData, 0, iv, 0, iv.Length);
                    Array.Copy(encodedData, iv.Length, data, 0, data.Length);
                    Array.Copy(encodedData, iv.Length + data.Length, signature, 0, signature.Length);

                    // validate the signature
                    var mac = hashAlgorithm.ComputeHash(iv.Concat(data).ToArray());

                    if (!mac.SequenceEqual(signature))
                    {
                        // message has been tampered
                        throw new ArgumentException();
                    }

                    symmetricAlgorithm.IV = iv;

                    using (var ms = new MemoryStream())
                    { 
 
                        using (var cs = new CryptoStream(ms, symmetricAlgorithm.CreateDecryptor(), CryptoStreamMode.Write))
                        {
                            cs.Write(data, 0, data.Length);
                            cs.FlushFinalBlock();//此处报 “填充无效，无法被移除”错误
                        }
                        return ms.ToArray();
                    }
                }
            }
        }

        public byte[] Encode(byte[] data)
        {
            byte[] encryptedData;
            byte[] iv;

            using (var ms = new MemoryStream())
            {
                using (var symmetricAlgorithm = CreateSymmetricAlgorithm())
                {
                    // generate a new IV each time the Encode is called
                    symmetricAlgorithm.GenerateIV();
                    iv = symmetricAlgorithm.IV;

                    using (var cs = new CryptoStream(ms, symmetricAlgorithm.CreateEncryptor(), CryptoStreamMode.Write))
                    {
                        cs.Write(data, 0, data.Length);
                        cs.FlushFinalBlock();
                    }

                    encryptedData = ms.ToArray();
                } 
 
            }

            byte[] signedData;

            // signing IV || encrypted data
            using (var hashAlgorithm = CreateHashAlgorithm())
            {
                signedData = hashAlgorithm.ComputeHash(iv.Concat(encryptedData).ToArray());
            }
            var test=iv.Concat(encryptedData).Concat(signedData).ToArray();
            return test;
        }

        private SymmetricAlgorithm CreateSymmetricAlgorithm()
        {
            var algorithm = SymmetricAlgorithm.Create();
            return algorithm;
        }

        private HMAC CreateHashAlgorithm()
        {
            var algorithm = HMAC.Create();
            algorithm.Key = "3c2d1f".ToByteArray();
            return algorithm;
        }
    }
}
//ToByteArray 扩展方法
public static byte[] ToByteArray(this string hex)
        {
            return Enumerable.Range(0, hex.Length).
                Where(x => 0 == x % 2).
                Select(x => Convert.ToByte(hex.Substring(x, 2), 16)).
                ToArray();
        }

解密 加密
[解决办法]
恭喜恭喜，接分接分。