c#加密类使用方法示例

using system;
using system.io;
using system.text;
using system.security.cryptography;
using system.web;

namespace encryption.app_code
{
    /// <summary>
    /// 加密码类
    /// </summary>
    public class encryption
    {
        /// <summary>
        /// 加密
        /// </summary>
        /// <param name="inputstring"></param>
        /// <returns></returns>
        public static string desencrypt(string inputstring)
        {
            return desencrypt(inputstring, key);
        }
        /// <summary>
        /// 解密
        /// </summary>
        /// <param name="inputstring"></param>
        /// <returns></returns>
        public static string desdecrypt(string inputstring)
        {
            return desdecrypt(inputstring, key);
        }
        /// <summary>
        /// 密匙
        /// </summary>
        private static string key
        {
            get
            {
                return "hongye10";
            }
        }
        /// <summary>
        /// 加密字符串
        /// 注意:密钥必须为８位
        /// </summary>
        /// <param name="strtext">字符串</param>
        /// <param name="encryptkey">密钥</param>
        /// <param name="encryptkey">返回加密后的字符串</param>
        public static string desencrypt(string inputstring, string encryptkey)
        {
            byte[] bykey = null;
            byte[] iv = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef };
            try
            {
                bykey = system.text.encoding.utf8.getbytes(encryptkey.substring(0, 8));
                descryptoserviceprovider des = new descryptoserviceprovider();
                byte[] inputbytearray = encoding.utf8.getbytes(inputstring);
                memorystream ms = new memorystream();
                cryptostream cs = new cryptostream(ms, des.createencryptor(bykey, iv), cryptostreammode.write);
                cs.write(inputbytearray, 0, inputbytearray.length);
                cs.flushfinalblock();
                return convert.tobase64string(ms.toarray());
            }
            catch (system.exception error)
            {
                //return error.message;
                return null;
            }
        }
        /// <summary>
        /// 解密字符串
        /// </summary>
        /// <param name="this.inputstring">加了密的字符串</param>
        /// <param name="decryptkey">密钥</param>
        /// <param name="decryptkey">返回解密后的字符串</param>
        public static string desdecrypt(string inputstring, string decryptkey)
        {
            byte[] bykey = null;
            byte[] iv = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef };
            byte[] inputbytearray = new byte[inputstring.length];
            try
            {
                bykey = system.text.encoding.utf8.getbytes(decryptkey.substring(0, 8));
                descryptoserviceprovider des = new descryptoserviceprovider();
                inputbytearray = convert.frombase64string(inputstring);
                memorystream ms = new memorystream();
                cryptostream cs = new cryptostream(ms, des.createdecryptor(bykey, iv), cryptostreammode.write);
                cs.write(inputbytearray, 0, inputbytearray.length);
                cs.flushfinalblock();
                system.text.encoding encoding = new system.text.utf8encoding();
                return encoding.getstring(ms.toarray());
            }
            catch (system.exception error)
            {
                //return error.message;
                return null;
            }
        }
    }
}