How safe is your money when you pay your friends with apps?

Millions of Americans are paying each other without actual paper cash ever changing hands.

It's all done through peer-to-peer services like Apple Pay, Venmo and Square Cash -- but are they secure and do they protect your privacy?

Consumer Reports put these P2P services to the test to see if they can be trusted to transfer your money and keep your data safe.

It's a convenience that's growing in popularity. From millennials to baby boomers, an estimated 79 million Americans will use a mobile peer to peer payment service this year.

"It's really easy like splitting a check at the table," said one user.

"Sometimes you have to send money to your parents or your siblings so it's a lot easier for me to do that," added another.

Throw in messages and emojis and it can be sort of fun.

But with consumers worried about data breaches and hacks, can P2P services be trusted? Consumer Reports rated 5 of them, focusing on privacy and security.

"We didn't find any of the services were so bad you shouldn't use them," said Tobie Stanger, Consumer Reports Money Editor.

Although there are differences consumers should know about. Apple Pay for instance was the only one to score top marks for data privacy.

"They try to take the least amount of data and keep the least amount of data to keep your privacy protected," said Stanger.

However, it's only available if both the sender and the receiver use an Apple smart phone, watch or tablet -- and a newer version at that.

In fact, that's one thing to note with P2P in general. You have to use the same service to exchange funds.

"So I have to have Zelle, you have to have Zelle. I have to have Venmo, you have to have Venmo," said Stanger.

Depending on which service you use, accounts are linked to your bank account, credit or debit card, prepaid card, or PayPal account. So if you do sign up for a P2P service, Consumer Reports recommends you opt for the highest app privacy and security settings possible, adding, for instance, a PIN or fingerprint authentication.

Also, as fun as the feed may be, with Venmo you really set it to keep your transactions private. Most important, Don't use P2P to send money to strangers.

"You should really only pay people that you know," said Stanger

Also you want to keep your app up to date. Hackers are always trying to find new vulnerabilities so make sure you are using the most recent version available.