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Juice Jacking: How to Charge Safely at Public USB Ports

Tap each term to learn how to charge safely at public USB ports.

What juice jacking is

Juice jacking is a name for attacks that exploit the fact that public USB charging ports and cables, at airports, cafes, and other shared locations, pass both power and data over the same connection, letting an attacker attempt to steal information or install malware on a connected device.

Why a USB cable carries both power and data

Most standard USB cables include both power lines and data lines in the same cord, meaning a connection you intend purely for charging can end up establishing a data link with whatever is on the other end of the port as well.

Using a charge-only (data-blocked) cable

A cable that has no data lines, or has them physically disabled, only supplies power with no data connection possible, making it one of the more reliable options for using a public charging port safely.

Using a small USB data blocker adapter

A small adapter placed between your cable and the charging port physically blocks the data pins while still letting power through, letting you keep using your existing cable while cutting off the data pathway.

Watch for a "Trust this computer?" prompt

If plugging into a public charger triggers a pop-up asking whether to trust the connected device, that's a sign a data connection is being attempted. Decline and unplug the cable right away.

Prefer a wall outlet when you can

Charging from a standard electrical outlet with your own power adapter, rather than a USB data port, avoids the data pathway entirely, making it the safest option for public charging when one is available.

Why airport and cafe chargers deserve some caution

It can be hard to know who actually maintains a public USB port, and a small tampering device hidden inside a cable or port isn't something you can spot by looking. Confirmed large-scale incidents of this kind of attack aren't especially common, but the fact that the structural possibility of a data connection exists at all is reason enough for a bit of caution.

A portable power bank is also a good option

The simplest precaution is carrying a charged portable power bank or battery pack. That way you never need to plug your device directly into a public port, sidestepping the data-connection risk entirely.

Frequently Asked Questions

I already used a public charger, should I be worried?

In the vast majority of cases, nothing happens beyond ordinary charging. But if you noticed an unusual pop-up during charging or your device has been behaving strangely since, running a security scan is a reasonable precaution.

Does wireless charging carry the same risk?

No. Wireless charging transfers power through electromagnetic induction with no data pins involved, so it's largely unaffected by the cable-based data-theft risk that juice jacking relies on.