[C#] 10进制转62进制，实现穷举指定位数的所有密码组合（暴力破解）

因为我们这里要穷举的密码包括0-9,a-z,A-Z共62个字符，所以我们采用62进制来遍历。

首先，我们实现一个10进制转62进制的方法。

        private static char[] charSet = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ".ToCharArray();
        //private static string[] charSet = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
        //                                      "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", 
        //                                      "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z", 
        //                                      "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
        //                                      "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z" };

        /// <summary>
        /// 将指定数字转换为指定长度的62进制
        /// </summary>
        /// <param name="value">要转换的数字</param>
        /// <param name="length">需要的长度</param>
        /// <returns>62进制表示格式</returns>
        public static string ConvertTo62(long value, int length)
        {
            string sixtyNum = string.Empty;
            if (value < 62)
            {
                sixtyNum = charSet[value].ToString().PadLeft(length, '0');
            }
            else
            {
                long result = value;
                //char[] ch = new char[length];
                while (result > 0)
                {
                    long val = result % 62;
                    //ch[--length] = charSet[val];
                    sixtyNum = charSet[val] + sixtyNum;
                    result = result / 62;
                }
                sixtyNum = sixtyNum.PadLeft(length, '0');
                //for (int i = 0; i < length; i++)
                //{
                //    ch[i] = '0';
                //}
                //sixtyNum = new string(ch);
            }
            return sixtyNum;
        }

进过测试发现把charSet定义成char类型比string的要快一点，但马中的计算也采用char的方式（我注释掉的代码）也要快一点。

Console.WriteLine(ConvertTo62(520, 5));//输出：0008o

因为520转换成为62进制是8o，不足5位前面加0补齐。

然后，我们就可以写一个方法来遍历指定长度的密码了。

        /// <summary>
        /// 遍历指定位数之间的所有组合
        /// </summary>
        /// <param name="minLength">最短位数</param>
        /// <param name="maxLength">最长位数</param>
        public static void testPassword(int minLength, int maxLength)
        {
            for (int i = minLength; i <= maxLength; i++)
            {
                long maxNum = (long)Math.Pow(62, i);
                for (long j = 0; j < maxNum; j++)
                {
                    Console.WriteLine(ConvertTo62(j, i));