Using mobile devices to store private data can be a big security risk in case you lose them and they are not conveniently protected. If you use these kind of devices you should follow some rules.
Password protection. You should use passwords or a PIN to access your device. This might be a very basic protection, but can stop casual attackers from accessing your data.
Cipher your data. Many mobile device include this capability built-in, but if yours don’t you should find some software which you can trust.
Use a firewall. If you need access to Internet you should use the same levels of protection as at home, so use a firewall to avoid attacks.
Use device lockdown functions. Many mobile devices include some way to wipe its contents remotely if someone steals it. Be sure to have copies of this information before wiping it.
If you don’t follow some simple rules your information might fall in the wrong hands.