Reading and Writing RFID Tags

RE: Reading and Writing RFID Tags

Gough Lui — Wed, 19 Dec 2018 01:17:39 GMT

I'd avoid any of the MiFare Classic 1K tags if you care about security. Retrieval of the keys is too easy with a bit of software running under Linux with a supported reader which could allow the data to be cloned. Many MiFare Classic 1K-compatible tags do not have genuine NXP chips which are even easier to break. You can see it in dumps as some of them have odd byte sequences "bcdefghi" in some areas. It is possible to make blocks permanently inaccessible if you set the trailer permission bytes to the wrong value (which I have done intentionally in the past). It is also possible to protect the tag with a code, but retain NDEF read capability (i.e. read only key permission is default, read/write is customised).

While the UID byte is pre-burned into the chip, it's also important to note there are "backdoored" Chinese versions of the chip that allow for UID reprogramming. Being just a memory store, these really don't do much in the way of real authentication, not like the DESFire series do which is more akin to a smart card running a kind of operating system.

MiFare Ultralight tags could be useful in some instances - don't know of UID clones of these, so perhaps using UID with their OTP bytes can also be used for security so that it doesn't get reprogrammed.

- Gough

RE: Reading and Writing RFID Tags

three-phase — Mon, 17 Dec 2018 20:11:36 GMT

I have never had anything to do with RFID take before either, so I look forward to reading your blogs on this.

Kind regards.

RE: Reading and Writing RFID Tags

Fred27 — Mon, 17 Dec 2018 12:45:01 GMT

I'm glad you're enjoying your first forays into the world of RFID and NFC. If you're doing some home automation you can probably limit your efforts to just reading the ID on the card and having a list of IDs (stored wherever is convenient) that you give access to. No need to write to tags.

Fred - another NFC implantee!

RE: Reading and Writing RFID Tags

e14phil — Mon, 17 Dec 2018 11:08:42 GMT

Awesome Great work!

I have had a play with this RFID kit before, its a really neat package with great arduino library support.

The reason I have played with it is that I have an NFC/RFID chip implanted in my hand. [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-87c36033-a254-404e-8e58-b6c48e27b4aa/contentimage_5F00_2516.png:16:16]

Feel free to read my blog about it here: Life as a Cyborg - Day 0 - Implantation

Keep up the good work! I cant wait to see what you do with it next.

e14Phil