string str = TextBox1.Text.Trim();
string str2 = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5");
Label1.Text = str2;
上例是转换为32位的方法
string str = TextBox1.Text.Trim();
string str2 = System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower.Substring(8, 16);
Label1.Text = str2;
上例是转换为16位小写的方法,其实是取了32位的9-25字符