Samsung SHS-2920 *DOES NOT WORK*
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Ages ago i was in discussions with John and a few others about Samsung maybe / maybe not having dropped support for NFC
here is the most detailed info i was able to get from a guy called Amal.
Hi guys,
I checked the PDF and I'm seeing ISO14443-A support, so the NTAG203 should work as it complies with that standard. There is a gotcha though... read on.
The confusion about NFC may be that most people don't understand exactly what NFC and RFID are, and how they overlap... marketers tend to muddy the waters, and unless you read spec sheets, it just gets confusing as all heck. The short run here is that there are several standards out there like ISO14443A which cover the air interface, the way the chip communicates over the air. There are several tag types that support ISO14443A, including Mifare Classic tags like the S50 and S70, as well as the Mifare Ultralight, Ultralight C, and NTAG203. These all qualify as ISO14443A tags. Check out http://en.wikipedia.org/wiki/MIFARE when you have a minute.
NFC, when applied to RFID tags only (not peer-to-peer NFC capabilities), simply means the NFC forum took 4 different RFID tag specifications (tag types) and overlaid specific memory schemas that those tags need to be programmed with if they are to be used as NFC tags. That means that the 4 types of RFID tags that already existed in the market, which have a specific arrangement of memory blocks (including OTP bits, UID bits, and read/write memory blocks), were chosen by the NFC forum and they created specific values for OTP bits and schemas on read/write memory blocks for those tags. All that means is, when an NFC device wants to read an "NFC Tag", it is reading an RFID tag and looking for those specific values in the OTP bits (in NFC speak these formatted OTP bits are called the Capability Container), which validates the RFID tag is formatted for use with NFC devices... then it reads the memory blocks looking for an NDEF Message envelope, and inside that rest the NFC Records. The records tell the NFC reader what to do, like open a URL or launch an app.
The Samsung door locks have never been NFC devices because they do not search the ISO14443A compliant RFID tag's memory for NFC formatted OTP bits, nor do they read memory blocks looking for NDEF messages or NDEF records. The door locks are simply reading the UID bits of the tag and that's all... so the door locks are simply RFID devices reading RFID tags, and NFC has nothing to do with it. As long as your tag is ISO14443A compliant, and the marketing literature can be believed, you're good to go. The NTAG203 is ISO14443A compliant, and it is a Type 2 NFC tag, meaning it can be formatted for use with NFC devices... but regardless of how it's formatted or what the content of its memory blocks is, the Samsung door lock only cares about the UID bits of the tag and will function as expected regardless of whether the NTAG203 is formatted for NFC or not.
A mention should be made in the case of Mifare Classic tags like the S50 and S70. Those tags have memory blocks arranged into sectors, and each sector is protected by a crypto-key structure called Crypto1. More "secure" applications use these older tag types to actually store application-relevant data in secure sectors, including some door lock applications. Because UID bits are generally readable by any RFID reader that supports ISO14443A, an additional unique identifier of some kind is sometimes stored in these secure memory sectors and the access control application compares both the UID bits, but also supplies crypto-keys to unlock the memory sector used by the application and reads that identifier as well. The Mifare Classic Crypto1 algorithm has been compromised and it is possible to eavesdrop a valid conversation between an application reader (like a door lock) and a valid tag, then decrypt the keys. This has caused some RFID products to drop the standard in favor of a more modern tag type, like the Mifare DESFire tag. The DESFire tag is NFC Type 4 compliant, meaning it too can be used as an NFC tag, but access to the memory blocks in the DESFire works a different way which we won't need to dive into now... suffice to say that it too is ISO14443-A compliant, so it should also work with the Samsung door lock (if they truly support all ISO14443A tag types).
This is the one way in which Samsung might have changed things so that the NTAG203 won't work... they could be writing secure elements to more advanced ISO14443A compliant RFID tags like the DESFire and opting not to work with simpler tags like the NTAG203 or Ultralight tag. Samsung's statement that it supports ISO14443-A tags is too general to be believed. Chances are they do not support every single ISO14443A tag type out there today, they probably only support tags with basic memory structures like the Ultralight and NTAG203... but if they were concerned about security, they may have narrowed their support of ISO14443A tags to only a select few like the DESFire tag. If it would be possible to ask a pointed question and get an exact list of ISO14443A tags that the door lock supports, that should get an answer.
My hunch is that they haven't bothered with the more complicated tag types and are still simply using simple, easy tags like the NTAG203, Ultralight, etc. I'd be very surprised if they have dropped support for these tags in favor of more expensive, exponentially more difficult to work with tags like the DESFire.
Thanks,
Amal ;) -
...snip...
Thanks for sharing that, the entire post was a very good bit of info from Amal who certainly knows NFC.
The section I've quoted is the assumption I've been operating under (bad form to assume, I know, but still) - the Samsung door lock I've received will read mifare tags and register them but is rejecting or failing to read NTAG203.
The part about them only registering the UID is why I felt safe ordering one and why I would prefer a door lock that only reads UID - it means that no matter what I do with the tag it will still open the door once it's registered to it, even if I later on change the info stored on the tag as I've been doing at random moments.
That this lock is reading the mifare tags but not the NTAG203 (I've tested quite a few) possibly means that it's also checking something else whether it's total storage available or tag type or whatever it may be.
The tags once registered still work after I have re-written the storage space so it can't be writing a key or password of some sort and must still be operating off a list of allowed UIDs, just perhaps also checking tag type in some manner.All in all, bloody infuriating. I've been regularly using far worse words than that.
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I also bought a 2920 to test this and it doesn't support any ISO 14443 A cards so this is basically a unit we would[b:2uo0tlou] strongly recommend ring barers avoid purchasing a SHS-2920![/b:2uo0tlou]
What a joke!
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Quite a surprise isn't it... the write up touts it's ISO14443A compatibility, then doesn't deliver.
Could we get some verification of which units you've tried and successfully used, John?
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Tested okay:
SHS-1321
SHS- the red oneOrdered to test:
SHS-2320
SHS-1311Should have some more results within a few weeks, wish someone else would be doing this though, I really don't have a lot of time to do thorough tests!
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Cool, thanks for that John!
The red one is the 2420/2421 I reckon.
I think the majority are sitting back and waiting to hear which ones work... -
[quote:zazyja4v]I think the majority are sitting back and waiting to hear which ones work...[/quote:zazyja4v]
Don't wait for me on this!
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It'll be another month before I can spring for another.
Everyone reading this, c'mon and take a punt, grab a lock and test it and report how you go here.
We'll get through them all a lot quicker and have a decent list of what works and what doesn't! -
What about the 1521 which seems to be the latest model? We use 2 of these at work and they are very good - they are the only reason why I have ordered the ring! I guess if it works most of our 25 staff will buy a ring as currently we make 20 of them use a code and not the tags.
Am happy to test but it looks like a couple of months before I'll get the ring!
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To be honest I don't think we will know until you try it, all I can offer is to be persistent and test it thoroughly before letting us know how you go.
Samsung have taken a slightly liberal approach to interpreting the standards which is quite frankly pissing me off. -
...because of following the NFC forum for sooooo long whilst still awaiting the shipment of my original kickstarter order... I have purchased the Samsung door lock and LOVE IT! Turns out the NFC ring can merely hold either - the unlock code or personal info - not two info-bits... Mmmmh Well, I keep snooping around in the blogs for more info, feeling like a well inforemd NFC ring geek without the very item that would make me a "fully respected" member... Until soon!
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Hi @chefraphael, which model did you end up buying? The NFC ring should be good on a doorlock regardless of what is programmed onto the inlay, most doorlocks will only bother reading the UID (which is fine by me!)
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I got the 2920 - looks snazy and everyone around me is now pondering to purchase one too! ha hhere is one oddity with the door lock - when programming a new NFC tag you have to "re-program" all the older ones too... hence I figgured it does not just "read" the UID...
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Ah. You may have issues with the 2920 reading NTAG203. The one I have here simply does not like NTAG chips and will only function with mifare cards/fobs.
I found it's key storage design to be ridiculous, every time you enter programming mode it dumps its memory and you have to enter each key again.
You can prove to yourself that it uses UID by programming the cards into the door lock, then re-writing what's on one of the cards - it should still work with the lock fine regardless of what you've personally got stored on it.
Now for the kicker, as I figured out (I still stare at the 2920 sitting half in and half out of it's box in the dunce corner of the lounge room) the 2920 doesn't like the NFC Ring.
This would be due to it's refusal to work with NTAG203, the NFC chip which the NFC Ring is based on.
