Computed string MD5 value under C #

Using System.Security.Cryptography;
public static string Getmd5hash (String input) {
    if (input = = null) {return
        null;
    }

    MD5 Md5hash = MD5. Create ();

    Converts the input string to a byte array and computes the hash data
    byte[] data = Md5hash.computehash (Encoding.UTF8.GetBytes (input));

    Create a Stringbuilder to collect bytes and create a string
    Stringbuilder Sbuilder = new Stringbuilder ();

    Loops through each byte of the hash data and formats it as a hexadecimal string for
    (int i = 0; i < data. Length; i++) {
        sbuilder.append (Data[i]. ToString ("X2"));
    }

    Returns a hexadecimal string return
    sbuilder.tostring ();
}

Test
Getmd5hash ("Hello, world!");
6cd3556deb0da54bca060b4c39479839

Reference: http://msdn.microsoft.com/zh-cn/library/s02tk69a (v=vs.110). aspx