BEST MOBILE PHONE FOR PRIVATE CALLS
Guys if you are a businessman and your calls privacy is much matter for you so you have to use such m mobile phones which having not security features instead of that you can use such a mobile phone can't be hack by someone so according to me you have to use such a old type keyboard mobile phones for calling someone which makes your call Much private.
HOW TO KEEP MOBILE PHONE FILES PRIVATE
If you are a Android user and wants to keep your information safe and private so you have to purchase such a security like high security passwords of your private accounts and you can also take a suggestion from an ethical hacker for it.
BEST ALL IN ONE SECURITY FEATURES IN ONE MOBILE PHONE
If you want all the above security feature in one device I have a suggestion for you for use iOS operator or iPhone for best security feature or best service it can be expansive but it take care of your data very much.