Shopping on mobile devices is incredibly convenient — and it’s popular.

By the end of last year, more than 50 percent of Americans had made purchases using a mobile phone. By 2020, mobile commerce is expected to account for 45 percent of the total U.S. e-commerce market.

But what few shoppers realize is that they may have downloaded apps that are trying to steal from them.

Here’s how it could happen: As you type in your credit card information at online checkout, some of the apps you’ve downloaded are watching and tracking your personal information in order to target advertising to you.

If that information is not safeguarded properly, or if you’ve unwittingly downloaded a phony app, your personal financial data could be siphoned off for identity theft or other fraud.

So — should you give up the convenience and online discounts of mobile shopping?

No. Just as you don’t stop driving because there’s a risk of a car crash, you don’t have to stop shopping via smartphone because there’s a risk of a data breach. But you should be aware of the risks and take steps to avoid them.

To start with, be choosy about the apps you download, said Karl Mattson, chief information security officer at City National Bank. He recommends getting apps only from a reputable app marketplace such as the Google Play Store or the Apple App Store.

Delete any apps on your phone that you don’t use regularly. And if you can’t remember where you got an app from, it’s probably best to delete it, Mattson said.

Shop Safe

It’s always a good time to ensure that your mobile shopping habits are smart ones. Consider these four tips from Mattson:

1. Shop on known and trusted networks. Never use an open network—such as the public wi-fi at an airport or coffee shop—to make purchases. Instead, use a network that is secured with a password, such as your home wi-fi network.

2. Keep your security settings up to date. As mobile usage increases, hackers are increasingly attacking mobile devices. The most secure mobile devices regularly release patches or updates to counteract the latest threats.

“Manufacturers such as Apple, Samsung and Google continually fix security issues and send out patches or updates,” Mattson said. “But if you don’t download the update, you won’t be protected from the most recent threats.”

3. Pay attention to reputations. The legitimacy of the site where you’re shopping is very important when you are online. Unlike a brick-and-mortar retailer, you’ll never meet most online shopkeepers or know how to track them down if you’re scammed.

“Check the reputation of the site you’re going to and verify that they are using a secure payment connection,” Mattson said. “If you’re unfamiliar with the site, search online for reviews before purchasing.”

4. Avoid alternative currencies. If an online seller asks you to pay with bitcoin or another crypto-currency, don’t do it.

“Someone asking for bitcoin online is essentially like a brick-and-mortar store owner asking you to pay in cash,” Mattson said. “It’s something to be wary of.”

He recommends using credit cards, or credit card-linked payment sites such as Venmo or Paypal, exclusively when shopping online. Credit cards typically provide better advantages to disputing unauthorized transactions than debit cards.

“If you use a debit card and someone steals the information, you’ve essentially given them access to your bank account,” Mattson said.