下面的类实现了文件的加密和解密操作，试验了几种文件类型均没有问题，现在和大家共享一下。

namespace MyCryptoHelp
{
 /// <summary>
 /// 异常处理类
 /// </summary>
 public class CryptoHelpException : ApplicationException
 {
  public CryptoHelpException(string msg):base(msg){}
 }

 /// <summary>
 /// CryptHelp
 /// </summary>
 public class CryptoHelp
 {
  private const ulong FC_TAG = 0xFC010203040506CF;

  private const int BUFFER_SIZE = 128*1024;
  
  /// <summary>
  /// 检验两个Byte数组是否相同
  /// </summary>
  /// <param name="b1">Byte数组</param>
  /// <param name="b2">Byte数组</param>
  /// <returns>true－相等</returns>
  private static bool CheckByteArrays(byte[] b1, byte[] b2)
  {
   if(b1.Length == b2.Length)
   {
    for(int i = 0; i < b1.Length; ++i)
    {
     if(b1[i] != b2[i])
      return false;
    }
    return true;
   }
   return false;
  }

  /// <summary>
  /// 创建Rijndael SymmetricAlgorithm
  /// </summary>
  /// <param name="password">密码</param>
  /// <param name="salt"></param>
  /// <returns>加密对象</returns>
  private static SymmetricAlgorithm CreateRijndael(string password, byte[] salt)
  {
   PasswordDeriveBytes pdb = new PasswordDeriveBytes(password,salt,"SHA256",1000);
   
   SymmetricAlgorithm sma = Rijndael.Create();
   sma.KeySize = 256;
   sma.Key = pdb.GetBytes(32);
   sma.Padding = PaddingMode.PKCS7;
   return sma;
  }

  /// <summary>
  /// 加密文件随机数生成
  /// </summary>
  private static RandomNumberGenerator rand = new RNGCryptoServiceProvider();

  /// <summary>
  /// 生成指定长度的随机Byte数组
  /// </summary>
  /// <param name="count">Byte数组长度</param>
  /// <returns>随机Byte数组</returns>
  private static byte[] GenerateRandomBytes(int count)
  {
   byte[] bytes = new byte[count];
   rand.GetBytes(bytes);
   return bytes;
  }

  /// <summary>
  /// 加密文件
  /// </summary>
  /// <param name="inFile">待加密文件</param>
  /// <param name="outFile">加密后输入文件</param>
  /// <param name="password">加密密码</param>
  public static void EncryptFile(string inFile, string outFile, string password)
  {
   using(FileStream fin = File.OpenRead(inFile),
       fout = File.OpenWrite(outFile))
   {
    long lSize = fin.Length; // 输入文件长度
    int size = (int)lSize;
    byte[] bytes = new byte[BUFFER_SIZE]; // 缓存
    int read = -1; // 输入文件读取数量
    int value = 0;
    
    // 获取IV和salt
    byte[] IV = GenerateRandomBytes(16);
    byte[] salt = GenerateRandomBytes(16);
   &