MD5 文件加密(用于文件唯一性识别)

/// <summary>
    /// 客户端MD5码的工具类
    /// </summary>
    public class MD5Util
    {

        /// <summary>  
        /// 通过MD5CryptoServiceProvider类中的ComputeHash方法直接传入一个FileStream类实现计算MD5  
        /// 操作简单，代码少，调用即可  
        /// </summary>  
        /// <param name="path">文件地址</param>  
        /// <returns>MD5Hash</returns>  
        public static string GetMD5ByMD5CryptoService(string path)
        {
            if (!File.Exists(path))
                throw new ArgumentException(string.Format("<{0}>, 不存在", path));
            FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);
            MD5CryptoServiceProvider md5Provider = new MD5CryptoServiceProvider();
            byte[] buffer = md5Provider.ComputeHash(fs);
            string resule = BitConverter.ToString(buffer);
            resule = resule.Replace("-", "");
            md5Provider.Clear();
            fs.Close();
            return resule;
        } 
    
        /// <summary>
        /// 通过HashAlgorithm的TransformBlock方法对流进行叠加运算获得MD5  
        /// 实现稍微复杂，但可使用与传输文件或接收文件时同步计算MD5值  
        /// 可自定义缓冲区大小，计算速度较快  
        /// </summary>
        /// <param name="file">文件地址</param>
        /// <param name="bufferSize">自定义缓冲区大小,默认1024 * 16 = 16K</param>
        /// <returns>MD5Hash</returns>
        public static string GetMD5ByHashAlgorithm(string path, int bufferSize = 16384)
        {
            if (File.Exists(path))
            {
                byte[] buffer = new byte[bufferSize];
                Stream inputStream = File.Open(path, FileMode.Open, FileAccess.Read, FileShare.Read);
                HashAlgorithm hashAlgorithm = new MD5CryptoServiceProvider();
                int readLength = 0;//每次读取长度  
                var output = new byte[bufferSize];
                while ((readLength = inputStream.Read(buffer, 0, buffer.Length)) > 0)
                {
                    //计算MD5  
                    hashAlgorithm.TransformBlock(buffer, 0, readLength, output, 0);
                }
                //完成最后计算，必须调用(由于上一部循环已经完成所有运算，所以调用此方法时后面的两个参数都为0)  
                hashAlgorithm.TransformFinalBlock(buffer, 0, 0);
                string md5 = BitConverter.ToString(hashAlgorithm.Hash);
                hashAlgorithm.Clear();
                inputStream.Close();
                md5 = md5.Replace("-", "");
                return md5; 
            }
            else 
            {
                throw new ClientException(ClientExceptionStatus.FILE_NOT_FOUND, "MD5码生成时找不到文件[" + path + "]");
            }
        }
    }

 

参考地址 : http://blog.csdn.net/qiujuer/article/details/19344527