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Introducing LockedUSB Adapter – USB Charger Firewall & Power Optimizer

Are you at risk of compromising your data while using that USB charging station at the Airport or in the Hotel room while traveling?

Is your USB device charging as fast as it can?

Do you want to charge your device at work without synching to your office computer?

Public Charging Stations - Hotels, Airports, Malls
Public Charging Stations – Hotels, Airports, Malls

As the folks at Krebs on Security report, “…those innocent-seeming charging stations could easily turn from saviors to devious data thieves. Those charging stations could easily be configured to copy data from your smartphone — or to even install malware on the device.”


Forbes - Security 6/02/2013
Forbes – Security 6/02/2013


PC Magazine security watch’s Max Eddy reports; “For this year’s upcoming Black Hat conference, the abstract for one talk in particular has caught peoples’ eyes. In it, researchers say they will demonstrate an innocuous-looking public charging station that can seize control of your iOS device.

Andy Greenberg at Forbes first drew our attention to the upcoming presentation titled “Mactans: Injecting Malware Into iOS Device Via Malicious Chargers.” Authors Billy Lau, Yeongjin Jang, and Chengyu Song write that their malicious charger—dubbed “Mactans”—is built off a BeagleBoard, three-inch square single-board computer from Texas Instruments.


NBC NEWS - Rosa Golijan
NBC NEWS – Rosa Golijan


That’s scary, but there is no reason to panic.

LockedUSB is an small USB adapter that allows secure charging of your personal devices. It enables portable devices to fast-charge, at their maximum rated current, anywhere there is a USB port. It physically disconnects the data lines, while keeping intruders away from your personal information.

What does it do?

  • Enables USB charging while disconnecting the USB data lines
  • Allows portable devices to fast-charge at their maximum rated current, reducing your charge time.
  • Exercise the Data lines to negotiate the maximum charging capability
  • ESD protected
  • Surge protection up to 2.3 Amps
  • Small package
  • USB type A Male to USB Type A Female Adapter

The Story

  Hearing your phone chirp desperately, in order to alert you that it’s running out of battery power is heartbreaking, especially when you’re stuck in an airport, hotel, or shopping center. Public charging stations are becoming more and more popular everywhere you go. Unfortunately, Identity Theft, Government surveillance, “rogue” and unstable chargers, are also on the rise.  I’ve searched the internet to find a firewall device, or specialized cable, that would provide the security I was looking for, and to my surprise there was nothing out there that offered secure charging capabilities.  I wanted to make a simple adapter, which I could use my own device’s cable, and have peace of mind that my personal data and information was secure.  I have designed a compact USB adapter that completely disconnects the data lines, while simultaneously providing the maximum allowed charging power so I can charge-up quickly and safely.

Proof of Concept for LockedUSB
Proof of Concept for LockedUSB

LockedUSB Charger Firewall and power optimizer was born, a single adapter that allows charging, while keeping the USB data lines physically disconnected from the host device. It also switches between multiple configurations, in order to guarantee maximum charging power which reduces charging time.

LockedUSB is very easy to use, just Plug it into the USB charging port, use your device’s charging cable and Done, you are Secure.

How does it work?

Inside the adapter we have a dedicated controller chip and current limiting power switch. An auto-detect feature monitors USB data line voltage, and automatically provides the correct electrical signatures on the data lines and allows portable devices to fast charge at their maximum rated current while keeping the data lines completely isolated.


  • Supports a USB DCP Shorting D+ Line to D– Line
  • Supports a USB DCP Applying 2.0 V on D+ Line and 2.7 V on D– Line (or a USB DCP Applying 2.7 V on D+ Line and 2.0 V on D– Line)
  • Supports a USB DCP Applying 1.2 V on D+ and D– Lines
  • Automatically Switch D+ and D– Lines Connections for an Attached Device
  • Hiccup Mode for Output Short-Circuit Protection
  • Provides CS Pin for USB Cable Compensation
  • Accurate ±10% Current-Limit at 2.3 A (typ)
  • Compatible with USB 2.0 and 3.0 Power Switch Requirements
  • Operating Range: 4.5 V to 5.5 V
Asus Nexus 7 Charging using LockedUSB Charger Firewall
Asus Nexus 7 Charging using LockedUSB Charger Firewall
Samsung Galaxy S3 Charging, All information and data is Secure
Samsung Galaxy S3 Charging, All information and data is Secure

Will it work with my device?

Yes, LockedUSB is designed to work with all USB powered devices, Smartphones, Tablets, MP3 players, Digital Cameras and more.

Here is a list of devices we have already tested:

  • iPhone (3GS, 4, 4S, 5)
  • Samsung Galaxy S2 and S3
  • iPad ( iPad2, Retina, iPad mini)
  • Nexus 7
  • HTC one
LockedUSB Adapter Prototype - Charger Firewall
LockedUSB Adapter Prototype – Charger Firewall

What we’ve done thus far…

We started with a hand-made prototype for a dedicated charger, while it was functional, it was very large, it didn’t work with the latest devices (Android and iPhones 5s) and it didn’t provide any protection from large current surges or energy transients.

  Then, we started looking for a controller that would exercise the data lines and provide the right signature and handshake signal to the host device, in order to request the maximum power available from the power source, while keeping the data lines disconnected from the charger simultaneously. After several prototypes, we were able to came up with a small adapter with all the features mentioned before.

As of right now:

Beta Prototype – Completed

Alpha Prototype PCB fabrication – Completed

Alpha Prototype PCB assembly – Completed

Preliminary case design – Completed

Beta PCB Schematics and layout – Completed

What’s next?

Your pledges will go towards building our initial goal of 1000 units, paying for the plastic injection mold tooling, the casing itself, test fixtures, assembly, packaging and shipping of rewards.

If this project is successfully funded, we will be able to source the Bill of Materials and PCB on larger quantities, which will allow us to keep the price down.

Manufacturing will be by a contract manufacturer, located here in the USA. We have already secured a quote, and time-line, for our initial production of 1000 units, with an option to manufacture up to 5000 units in the same time frame. Ultimately, we will be looking for turn-key services. Initially we will be using assembly services only, and we will be programming and testing the boards ourselves.

We have also secured a quote for sourcing the Electronics components in quantity from Avnet North America (Atlanta GA office) and Arrow Electronics for 1000 units (they have at least 10,000 units in-stock of all components needed on the Bill of Materials)

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