转载 URL短地址压缩算法
文章转载http://www.nowamagic.net/webdesign/webdesign_ShortUrlInTwitter.php
/// <summary> /// 生成salt /// </summary> /// <returns></returns> public static string GenerateSalt() { byte[] data = new byte[0x10]; new RNGCryptoServiceProvider().GetBytes(data); return Convert.ToBase64String(data); }
public static string[] ShortUrl(string url) { //可以自定义生成MD5加密字符传前的混合KEY string key = "anech"; //要使用生成URL的字符 string[] chars = new string[]{ "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" , "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" }; //对传入网址进行MD5加密 string hex = MD5(key + url); string[] resUrl = new string[4]; for (int i = 0; i < 4; i++) { //把加密字符按照8位一组16进制与0x3FFFFFFF进行位与运算 int hexint = 0x3FFFFFFF & Convert.ToInt32("0x" + hex.Substring(i * 8, 8), 16); string outChars = string.Empty; for (int j = 0; j < 6; j++) { //把得到的值与0x0000003D进行位与运算,取得字符数组chars索引 int index = 0x0000003D & hexint; //把取得的字符相加 outChars += chars[index]; //每次循环按位右移5位 hexint = hexint >> 5; } //把字符串存入对应索引的输出数组 resUrl[i] = outChars; } return resUrl; } public static string MD5(String input) { byte[] res = new MD5CryptoServiceProvider().ComputeHash(Encoding.Default.GetBytes(input)); return BitConverter.ToString(res).Replace("-", ""); }