Apple won't allow "antivirus" apps in the App Store, but there are many "security" apps available. For example, Norton Mobile Security costs $14.99 per year, and Lookout Premium costs $29.99 per year. But do these apps actually do anything?

You don't need an antivirus app for your iPhone. You won't find any in the App Store. So what do these "security" apps do? Are they useful, and how exactly are they protecting you?

Is Norton Mobile Security Any Good?

Let's take a look at Norton Mobile Security, which is a free download but requires at $14.99 yearly subscription fee. It has three features: Wi-Fi Security, Web Protection, and OS Alerts.

Wi-Fi Security informs you whether your Wi-Fi network is "compromised." Specifically, Norton's website says the app checks for SSL stripping, SSL decryption, content manipulation, suspicious network hardware, and hotspot reputation. This check is performed every time you connect to a new Wi-Fi network.

Basically, Norton is checking to ensure you aren't connected to a dangerous public Wi-Fi network that's attempting to snoop on or modify your traffic. That could help you spot a dangerous public Wi-Fi hotspot. You shouldn't have to worry if you're connected to a trusted Wi-Fi network at home or work---or if you just use mobile data.

Web Protection connects your phone to a VPN when you enable it. Norton uses this VPN to scan your traffic for known-dangerous websites. It can then prevent you from accessing them. For example, if you were navigating to a phishing website, Norton could block it.

This isn't the type of VPN you usually think of. Norton is using an "on-device VPN"---when you enable the VPN, your traffic is sent to the Norton app on your device, and the Norton app checks it against a blacklist and blocks any known-based websites. This isn't like a typical VPN that sends your traffic over the network in an encrypted form. Norton offers that as part of Norton Secure VPN, which requires an extra monthly fee.

This could theoretically be useful, but it's worth noting that Safari for iPhone and iPad has a built-in dangerous website blocker. Just head to Settings > Safari > Fraudulent Website Warning to ensure it's enabled.

It's possible Norton will catch more threats than Apple's protection does, but it would really just protect you against phishing websites and scams. Having Web Protection enabled will use a bit more battery life in the background, too. And, as long as you have an up-to-date operating system, the Safari browser is safe from attacks. There's no way for a malicious website to download dangerous software to your phone from outside the App Store as long as you don't install any potentially dangerous configuration profiles.

If you do want a VPN to protect your traffic on public Wi-Fi, Web Protection doesn't offer that. We recommend other VPNs.

The third icon, OS Alerts, will provide a notification when your iPhone or iPad's operating system is out of date. It's essential to keep your device updated so that you have the latest security patches. However, you don't really need this feature. On an iPhone or iPad, you can head to Settings > General > Software Update and ensure automatic updates are enabled. Your device will then automatically install them.

OS Alerts might provide you with a faster alert when an update is available, but there's probably no harm in waiting a day to install the update automatically.

We can think of one advantage to this app: OS Alerts would inform you if your iPhone or iPad is so old and out of date that Apple is no longer supporting it with security updates.

We Don't Recommend Norton, But It's Fine

We don't think Norton's features justify that $14.99 per year price tag. But, if you or someone you know feels better with some sort of security app installed, Norton isn't actively harmful. Feel free to use it.

Related: What's the Best Antivirus for iPhone? None!

Is Lookout for iPhone Helpful?

Lookout is another popular iPhone security application. It has some extra features, but it's also more expensive. Here are Lookout's features include:

• System Advisor: Like OS Alerts in Norton, Lookout can tell you if you need to update your operating system. Apple's Settings app can alert you of this and even update the iOS operating system automatically.
• Safe Browsing: Like Web Protection in Norton, this feature also provides a VPN that checks for potentially dangerous websites.
• Safe Wi-Fi: Like Wi-Fi Security in Norton, this alerts you to potentially dangerous public Wi-Fi hotspots after you've connected to them.
• Breach Report: Lookout can inform you about security breaches---for example, if a service you use is compromised and leaks your password. Services like "Have I Been Pwned?" can do that for free.
• Identity Protection: For an extra fee, Lookout offers a credit monitoring service and similar tools. You even get identity theft insurance to cover legal costs and related expenses associated with identity theft. Tools like CreditKarma offer some free credit monitoring services.
• Missing Device: Lookout provides tools to help locate your iPhone if you lose it. This is built into your iPhone with Apple's Find My iPhone. However, Lookout can send you an alert when someone removes your SIM card or enables airplane mode---that's something extra.

Lookout can tell you if your iPhone's OS needs an update or track your lost phone for free---both things that your iPhone can normally do without any extra software---but other features will cost you. Lookout Premium includes most of the other features here, and it costs $2.99 per month or $29.99 per year. Identity protection and insurance require Premium Plus for $9.99 per month or $99.99 per year.

We Don't Recommend Lookout, But It's Also Fine

We wouldn't recommend Lookout on iPhone, either. Like Norton, Lookout duplicates some security features found in iOS and some that are available separately for free. With Lookout's more expensive Premium Plus tier, you're basically just paying another $70 on top of the regular price for a credit monitoring service sold through Lookout's iPhone app. That's not really an iPhone security feature.

But, if you or a family member feel better with these services, feel free to pay for them! They won't be actively harmful to your iPhone.