NEW YORK -- You may think you know what's in your child's phone, but keeping up with changing technology is no simple task.
Eyewitness News talked to an expert about the latest ways to keep your kids safe.
"There is no such thing as privacy for children," retired Naperville, Illinois, Detective Richard Wistocki said.
Wistocki said many parents make the mistake of giving children smartphone privacy.
"You should have the code, the swipe code to get into the phone, the numbers to get into that phone and have the right to get into that phone anytime you want," he said.
Wistocki is now a private technology consultant for BeSure Consulting, and holds seminars around the country to educate kids, parents and law enforcement about the latest smartphone concerns and apps which can hide pictures and videos, and act as "vaults."
"The most widely used vault looks like a calculator, works like a calculator, and kids will hide all these pictures and parents have no idea," Wistocki said.
There are several different versions of those fake calculator apps, but many have to be purchased or downloaded through app stores that have a verification process, which parents can also monitor.
Wistocki also highlighted Snapchat's feature which can hide past "memories," like old stories and pictures. It's an option called "My Eyes Only."
Snapchat said it's designed so users can hand their phones to friends "without being worried they might catch an eyeful of something meant just for" them.
"So the parent grabs it, they see 'My Eyes Only' on there, wham, they hit that, put the code in," Wistocki said. "If there is a code pad there, then they are hiding stuff in their stories, in their vault."
Snapchat said users must be at least 13, and its Safety Center said parents should discuss safety with teens. If they believe teens are in danger using the app, Snapchat said parents should deactivate their account with the username and password.
Snapchat also said "built-in parental control settings" are an option.
Snapchat's Safety and Education Overview
Snapchat Safety Center
Wistocki said parents should also take phones away at bedtime.
"When you allow your child to charge their devices in their rooms at night, you're sleeping, they shut the door so you can't hear them, they don't need to talk," he said. "It's typing, reading."
And you may want to turn off two-step authentication on your teen's phone if you're using apps to track and monitor your kids, he said.
Wistocki said improved two-factor authentication can make it difficult for parents to use third-party monitoring software.
"Because now, if there is a third party going in there to look at the stuff, it sends the owner an email, you must change your password," he said. "So now, no one can monitor."
However, Apple and data experts urge all customers to use two-factor authentication for all devices for data security.
MORE TIPS FOR TEEN PHONE SAFETY
Illinois Attorney General's Office Information on Cyberbullying
Illinois Attorney General's Office Guide to Safeguarding Children
Chicago Children's Advocacy Center: Internet Safety
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How to keep your kids safe on their smartphones