md5加密方法

/// <summary>
/// md5加密
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static string GenerateMD5(String str)
{
MD5 md5 = new MD5CryptoServiceProvider();
//byte[] data = System.Text.Encoding.Default.GetBytes(str);
byte[] data = Encoding.UTF8.GetBytes(str);
byte[] result = md5.ComputeHash(data);
String ret = "";
for (int i = 0; i < result.Length; i++)
ret += result[i].ToString("x").PadLeft(2, '0');
return ret;
}