用C#实现Base64处理，加密解密，编码解码

using System;
using System.Text;

namespace Common
{
        /// <summary>
        /// 实现Base64加密解密
        /// 作者：周公
        /// 时间：2007
        /// </summary>
        public sealed class Base64
        {
                /// <summary>
                /// Base64加密
                /// </summary>
                /// <param name="codeName">加密采用的编码方式</param>
                /// <param name="source">待加密的明文</param>
                /// <returns></returns>
                public static string EncodeBase64(Encoding encode, string source)
                {
                        byte[] bytes = encode.GetBytes(source);
                        try
                        {
                                encode = Convert.ToBase64String(bytes);
                        }
                        catch
                        {
                                encode = source;
                        }
                        return encode;
                }

                /// <summary>
                /// Base64加密，采用utf8编码方式加密
                /// </summary>
                /// <param name="source">待加密的明文</param>
                /// <returns>加密后的字符串</returns>
                public static string EncodeBase64(string source)
                {
                        return EncodeBase64(Encoding.UTF8, source);
                }

                /// <summary>
                /// Base64解密
                /// </summary>
                /// <param name="codeName">解密采用的编码方式，注意和加密时采用的方式一致</param>
                /// <param name="result">待解密的密文</param>
                /// <returns>解密后的字符串</returns>
                public static string DecodeBase64(Encoding encode, string result)
                {
                        string decode = "";
                        byte[] bytes = Convert.FromBase64String(result);
                        try
                        {
                                decode = encode.GetString(bytes);
                        }
                        catch
                        {
                                decode = result;
                        }
                        return decode;
                }

                /// <summary>
                /// Base64解密，采用utf8编码方式解密
                /// </summary>
                /// <param name="result">待解密的密文</param>
                /// <returns>解密后的字符串</returns>
                public static string DecodeBase64(string result)
                {
                        return DecodeBase64(Encoding.UTF8, result);
                }
        }
}