What is a data blocker?
Reviewed by Anthon Wansland
Head of Product & Co-Founder
Serus is a privacy company with paid tools to find and remove your personal data. This page is free and based on official sources.
Definition
A data blocker is a small USB adapter that lets a device charge while blocking the data wires, so a public charging port can't send or receive files or code. It is often called a USB condom.
- Category
- Security
- Also called
- USB data blocker, USB condom, charge-only adapter
- Last updated
Sources checked: fcc.gov
Last verified against the official page:
A USB port carries power and data through separate wires. A data blocker sits between your cable and the port and only passes the power through. A charge-only cable does the same job without an adapter.
Why people use one
The risk is called juice jacking. The FCC explains that bad actors can load malware onto public USB charging stations, or leave cables attached, to reach devices while they charge. The FCC also states that it isn't aware of any confirmed instances of it occurring, so this is a precaution rather than a common daily danger.
An example
You land at an airport with 5% battery and plug your phone into a free charging kiosk. If the port is tampered with and your phone allows a data connection, it could be reached. With a data blocker or a charge-only cable, the data pins aren't connected, so there's nothing to reach.
What the FCC recommends
The FCC's tips are to carry your own charging-only cable from a trusted supplier, choose "charge only" if a station asks what to do, use an AC power outlet when you can, and carry an external battery.
Data blocker vs. similar terms
- Charge-only cable is a cable with no data wires, which gives the same protection.
- Ad blocker or tracker blocker are different things: software that stops websites from loading ads or tracking scripts. They don't protect a charging port.
- Write blocker is a forensic tool that stops a computer changing a drive it reads. It isn't the same thing either.
How to protect yourself
- 1
Carry your own cable and charger
The FCC suggests bringing your own charging-only cable from a trusted supplier, and plugging it into an AC outlet when possible.
- 2
Choose "charge only"
If your phone asks whether to trust the computer or allow data transfer after you plug it in, pick the charge-only option or decline.
- 3
Bring a battery pack
An external battery avoids public ports altogether.
- 4
Don't use cables you find
Don't plug in a cable or drive that you didn't buy or that was left in a public place.
See where your personal data is exposed
Serus finds it on data brokers and people-search sites and removes it.
Frequently asked
Is juice jacking real?
The FCC says bad actors can load malware onto public USB charging stations, but it isn't aware of any confirmed instances of it occurring. Using your own cable and outlet is a simple precaution.
Do I need a data blocker if I have a charge-only cable?
No. A charge-only cable has no data wires, so it gives the same protection.
Does a data blocker stop phishing or hacking in general?
No. It only stops data moving through a USB charging port. It doesn't help against phishing, malware you download or weak passwords.
Sources
Something wrong or out of date? Tell us and we'll re-check it.