MD5加密在Net framework 4.5下面会警告过时

users.Password = Md5Hash(txt_Phone.Value.ToString().Trim());
public String Md5Hash(String pwd)
{
MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();
byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(pwd));
StringBuilder sb = new StringBuilder();
for (int i = 0; i < data.Length; i++)
{
sb.Append(data[i].ToString("x2"));
}
return sb.ToString();
}