The 5 secret iPhone apps people use to cheat on their partners.

Once upon a time, cheaters were caught by a smudge of lipstick on their collar, a whiff of someone else’s cologne, a phone number in their pocket.

Today, like everything else, cheating’s gone tech.

While not all unfaithful folks will be as blatant as signing up for Ashley Madison, there are a number of apps out there designed to make a cheater’s life easier.

These are the five most popular.

1. KYMS Private Photos

If you’re at the point where you’re suspiciously snooping through your partner’s phone, there’s an innocuous symbol you may as well look out for: a calculator. If there’s a “calculate app” named “Ky-calc” then he or she has something they don’t want you to see.

Type the correct PIN number into the fully functional calculator and you'll find a password-protected vault for photos and videos.

2. Tiger Text

No, this isn't named after the philandering golfer. In fact, it wasn't even created for cheaters at all.

Designed for 'business deals', this app has been co-opted by the unfaithful thanks to one of its nifty features: messages automatically erase. Think Snapchat for texts. One minute it's there, the next....

There are a number of apps out there with similar functions, eg. Wickr, Invisible Text and Gliph.

3. Fox Private Message

If you ever walk into a room and notice your partner shaking their phone, chances are they have this app.

A sudden move of the device will automatically close this stealthy app, protecting your messages from prying eyes.

On top of that, it's password protected, there's no app icon and you can delete all communication remotely by sending a text message to your phone.

4. Vaulty Stocks

Similar to Private Photos, the Vaulty Stocks app isn't what it first seems. No, your partner hasn't developed a sudden interest in the goings on of Wall St. Yes, they're hiding something.

It looks and works like a real stocks app, but its true purpose is to store private photographs and video.

Beware when snooping through this one, though. If you enter the incorrect password, it triggers the phone's camera to snap a picture of you.

5. Nosy Trap

This is another one of which to be wary. Especially if you don't want to get caught while trying to catch your cheating spouse.

The owner of the device simply activates the app when leaving their phone unattended, and anyone one who then touches it gets photographed.

Oh wow.

Proceed with caution.

Have you caught someone cheating before? Send your story to submissions@mamamia.com.au