The RFID cards that I brought have numbers printed on the back of them. That showed me the data that was being sent when the card transmitted its information.
I started by building a RFID card reader (more details in a future article). The actual data is transmitted by the card effectively shorting the coil out - this applies an additional load to the transmitter in the reader, which can be detected. For a detailed description, have a look a this page. Because the transitions are in the middle of each bit, you can ensure that you have locked onto valid data. If you want to transmit a 1, the transition would be from low to high, and if you want to transmit a 0, the transition would from from high to low. With Manchester encoding, there is always a transition in the middle of a bit. One interesting feature of the data transfer between the card and the reader, is that data is encoded using Manchester Encoding, which is a way of encoding data so that it can be transmitted over a single wire ensuring that the clock information is able to be recovered easily. I will describe what this pattern actually means in the next page. If the bit pattern does not match an authorised one, then the door won't unlock. If the bit pattern matches one that is authorised, the door will be unlocked. The reader then reads this bit pattern, and passes it onto the door controller. Once powered up, the tag modulates the bit pattern that is programmed into the tag using a signal that the reader can detect. The energy from the reader has dual use firstly, it provides power to run the card, and secondly, it provides a communication medium for data to be transmitted.
When the tag is brought into close proximity to a reader, energy is coupled inductively from the reader to the microchip within the tag. The tag consists of a coil of wire, connected to a microchip. I will describe the 125 kHz standard that is common for access control mechanisms.ġ25 kHz RFID tags are commonly encased in a business card sized piece of plastic, or a round disk. There are a number of standards, encoding formats, and frequencies in common use. RFID, or Radio Frequency IDentification is the term used to describe a wide variety of standards that allow data stored within electronic 'tags' to be read by a reader without using wires. And remember, with great power comes great responsibility! So there you go - I hope you enjoy making this project.
Will this key let you into anybodies RFID protected office? Yes it will, assuming a couple of things are trueġ) The have to be using 125kHz RFID tags that use the same encoding standard as I have designed this project for, and,Ģ) You have to have access to the number printed on the back of the tag - with that number, you can simply key it into the Universal RFID key, and it will emulate that tag. I have decided to publish this, as more people should be aware of the design flaws that are inherent in older RFID implementations, and to allow others to make their own universal key. The key I made works beautifully both on my garage door, as well as a number of other RFID readers I have tried! So, in typical fashion, I built my own reader hardware so I could have a look at the data from a card, and created my own version of the Universal RFID key.
#PROUSB HOTEL CARD SYSTEM SERIAL KEY CODE#
The original author didn't release source code for their project, but they left enough clues that I could follow. For the next couple of days, I couldn't get the image of the card out of my mind the project reminded me of how much I wanted to build a RFID spoofer myself. Even my current employer uses them.Ī while ago, I was looking at Hack A Day, and I saw an amazing project that somebody had made. Researchers have demonstrated cloners of all varieties, but simple RFID tags are still being used for access control. We have known that the cheaper RFID technologies were pretty insecure for a number of years. Even I recently purchased a RFID door lock on eBay for $15 to lock my garage (so my front neighbor could get tools if he wanted to). RFID projects have been pretty prominent recently, ranging from projects here in Instructables, to our local Silicon Chip magazine in Australia publishing a RFID door lock project in their November issue.