C#生成注册码的实例代码

string t = datetime.now.ticks.tostring();

            t = deskey.desencrypt(t, deskey.deskeystr);
            string[] strid = new string[t.length];//
            for (int i = 0; i < t.length; i++)//把字符赋给数组
            {
                strid[i] = t.substring(i, 1);
            }
            string s = "";
            random rdid = new random();
            for (int i = 0; i < 9; i++)//从数组随机抽取字符组成新的字符生成机器三
            {
                s += strid[rdid.next(0, strid.length)];
            }

class deskey
    {
        public const string deskeystr = "blue2013";

        #region des加密
        /// <summary>
        /// des加密
        /// </summary>
        /// <param name="ptoencrypt">需要加密的字符串</param>
        /// <returns>加密后的字符串</returns>
        public static string desencrypt(string ptoencrypt, string deskeystr)
        {
            try
            {
                descryptoserviceprovider des = new descryptoserviceprovider();
                byte[] inputbytearray = encoding.default.getbytes(ptoencrypt);
                des.key = asciiencoding.ascii.getbytes(deskeystr);
                des.iv = asciiencoding.ascii.getbytes(deskeystr);
                memorystream ms = new memorystream();
                cryptostream cs = new cryptostream(ms, des.createencryptor(), cryptostreammode.write);
                cs.write(inputbytearray, 0, inputbytearray.length);
                cs.flushfinalblock();
                stringbuilder ret = new stringbuilder();
                foreach (byte b in ms.toarray())
                {
                    ret.appendformat("{0:x2}", b);
                }
                ret.tostring();
                return ret.tostring();
            }
            catch
            {

                return "";
            }

        }
        #endregion

        #region des解密
        /// <summary>
        /// des解密
        /// </summary>
        /// <param name="ptodecrypt">加密后的字符串</param>
        /// <returns>解密后的字符串</returns>
        public static string desdecrypt(string ptodecrypt, string deskeystr)
        {
            try
            {
                descryptoserviceprovider des = new descryptoserviceprovider();

                byte[] inputbytearray = new byte[ptodecrypt.length / 2];
                for (int x = 0; x < ptodecrypt.length / 2; x++)
                {
                    int i = (convert.toint32(ptodecrypt.substring(x * 2, 2), 16));
                    inputbytearray[x] = (byte)i;
                }

                des.key = asciiencoding.ascii.getbytes(deskeystr);
                des.iv = asciiencoding.ascii.getbytes(deskeystr);
                memorystream ms = new memorystream();
                cryptostream cs = new cryptostream(ms, des.createdecryptor(), cryptostreammode.write);
                cs.write(inputbytearray, 0, inputbytearray.length);
                cs.flushfinalblock();

                stringbuilder ret = new stringbuilder();

                return system.text.encoding.default.getstring(ms.toarray());
            }
            catch
            {

                return "";
            }
        }
        #endregion

 

    }