Develop Bugs

[Q] Read NFC tags with screen off?

Is it possible?

It should read and wake the device, no?

As I understand the technology, this isn't possible with the screen completely off. It's a security feature that the secure element only turns on when the screen turns on. So it should be a hardware limitation not a software one.
Sent from my Galaxy Nexus using Tapatalk

the thing is, I can't seem to read with the screen on but no unlocked yet....
só its kinda boring having to turn it on, then unlock the read the tag...

lucasmine said:
the thing is, I can't seem to read with the screen on but no unlocked yet....
só its kinda boring having to turn it on, then unlock the read the tag...
Click to expand...
Click to collapse
It depends on the app. Some apps unlock it automatically like Google Wallet. So it depends on if the dev has added that feature.
Sent from my Galaxy Nexus using Tapatalk

RTContent said:
As I understand the technology, this isn't possible with the screen completely off. It's a security feature that the secure element only turns on when the screen turns on. So it should be a hardware limitation not a software one.
Sent from my Galaxy Nexus using Tapatalk
Click to expand...
Click to collapse
correct, the nfc card turns off when screens off

elmo61 said:
correct, the nfc card turns off when screens off
Click to expand...
Click to collapse
My understanding is that the NFC service is disabled not the hardware and this could be changed with a custom ROM.

I've tried it both ways, screen off and screen on with Google Wallet and though it takes more time for it to open the app and prompt me for my PIN when I just pull it out of my pocket and tap it, it does seem to recognize the NFC tag (at the POS at least) even with screen off.
So I'd have to agree, I think it's up to the dev.

I'm hoping that one of the NFC devs sees this and can request one of the ROM developers to allow the NFC service to be active when the screen is off. I'd make this request myself over on the One X developer forum but I don't yet have the required 10 posts

RTContent said:
It depends on the app. Some apps unlock it automatically like Google Wallet. So it depends on if the dev has added that feature.
Sent from my Galaxy Nexus using Tapatalk
Click to expand...
Click to collapse
Google Wallet doesn't unlock the device in ICS - it did in Gingerbread. It did this because the NFC Service and polling loop started when the device was awake, yet still locked. This changed in ICS.
phanover said:
My understanding is that the NFC service is disabled not the hardware and this could be changed with a custom ROM.
Click to expand...
Click to collapse
It is the service being disabled.
http://grepcode.com/file/repository...4.0.1_r1/com/android/nfc/NfcService.java?av=h
See ApplyRouting where checks are explicitly made to see if the screen is unlocked before enabling. In theory the service could be modified and compiled into a custom rom to behave like Gingerbread (where it worked with the screen locked but on).
In Gingerbread ApplyRouting was maybeEnableDiscovery and the only check was mScreenOn
http://grepcode.com/file/repository...apps/2.3.3_r1/com/android/nfc/NfcService.java

krohnjw said:
Google Wallet doesn't unlock the device in ICS - it did in Gingerbread. It did this because the NFC Service and polling loop started when the device was awake, yet still locked. This changed in ICS.
It is the service being disabled.
http://grepcode.com/file/repository...4.0.1_r1/com/android/nfc/NfcService.java?av=h
See ApplyRouting where checks are explicitly made to see if the screen is unlocked before enabling. In theory the service could be modified and compiled into a custom rom to behave like Gingerbread (where it worked with the screen locked but on).
In Gingerbread ApplyRouting was maybeEnableDiscovery and the only check was mScreenOn
http://grepcode.com/file/repository...apps/2.3.3_r1/com/android/nfc/NfcService.java
Click to expand...
Click to collapse
So, it's definitely possible to enable NFC with the screen on but still locked. But what about the OP's main question? Is it possible to keep the NFC service active 24/7 with some hackery?

LoveNFC said:
So, it's definitely possible to enable NFC with the screen on but still locked. But what about the OP's main question? Is it possible to keep the NFC service active 24/7 with some hackery?
Click to expand...
Click to collapse
Possibly I haven't looked at that part of the service, the code's all there though (assuming there isn't anything in the blobs preventing it).

how about read NFC tag in lock screen?

krohnjw said:
Google Wallet doesn't unlock the device in ICS - it did in Gingerbread. It did this because the NFC Service and polling loop started when the device was awake, yet still locked. This changed in ICS.
It is the service being disabled.
http://grepcode.com/file/repository...4.0.1_r1/com/android/nfc/NfcService.java?av=h
See ApplyRouting where checks are explicitly made to see if the screen is unlocked before enabling. In theory the service could be modified and compiled into a custom rom to behave like Gingerbread (where it worked with the screen locked but on).
In Gingerbread ApplyRouting was maybeEnableDiscovery and the only check was mScreenOn
http://grepcode.com/file/repository...apps/2.3.3_r1/com/android/nfc/NfcService.java
Click to expand...
Click to collapse
can this be include in one existing apps (the one you create) or only in rooted device ?

Bardamuz said:
can this be include in one existing apps (the one you create) or only in rooted device ?
Click to expand...
Click to collapse
You'd need to modify the actual NFC service - so it would need to be part of a modified ROM.

I think that is not possible, "action" in NFC is kinda to emulate user activity..., I don't that that "user activity" can be done when screen off/locked...

fajarep said:
I think that is not possible, "action" in NFC is kinda to emulate user activity..., I don't that that "user activity" can be done when screen off/locked...
Click to expand...
Click to collapse
when screen is off NFC stop working , except if you root the device it will not be possible to make it run when screen is off/locked

Evening gents,
I have a simmilar requirement for a project - to enable the NFC-read capability with the screen off / device locked.
I understand this is disabled as a security measure, to stop running instructions from external tags without user knowledge.
However, does this "lock" apply to simply reading a tag, and confirming the responce?
I read in various places that there is a "mod" to allow NFC with the screen locked.
Would this need to be done on a rooted phone?
My intention is completely legit - the final app would be installed from the Play store, with permissions required being accepted by the user etc as normal.
Could this "Read NFC with screen off" be authorised and enabled as part of the apk payload installation?
(FWIW, if this is possible, I would need to "ping" (run NFC search, read responce, confirm tag ID) every x-minutes).
THX

It should be possible to "override" the security feature of turning off the NFC reader when your screen is off through a custom, modified kernel. And to those who say that it's a hardware limitation, it's not. At least not on my phone, I used to have this before, on an older version of Android. Now I'm running a CM based rom, on Android 4.4.4, and it doesn't seem to detect NFC cards at all when the screen is off.
But I like it this way, so I'm not complaining.

Hi, in AOKP KK you can set the NFC Polling Mode to "screen off", "screen on locked" and "screen on unlocked (standard)"
Maybe look af github for the code.
greetings from Germany

[Q] Can I use my GN NFC with a Wiegand Proximity Reader?

I'm not sure if the GN Near Field Communication (NFC) is the same tech as the Wiegand Proximity cards and readers we have at work. Does anyone know if it would be possible to have my phone transmit my key number so that I could use it on the door sensors?
I asked the IT guy at work and he was not sure. He told me our card readers are Wiegand Prox(imity) 126 bit readers. The access key card I have is broadcasting a number code which I know what that is. I was hoping to be able to program this number code into the GN NFC and use it as a spare access key card.
Anyone?
Jim

Android is not capable of card emulation currently.

OK thanks. By currently do you mean they have the physical capability but no software has been written? Are you aware of plans to add this in the future?
Jim

calaski8123 said:
OK thanks. By currently do you mean they have the physical capability but no software has been written? Are you aware of plans to add this in the future?
Jim
Click to expand...
Click to collapse
After looking around the NFC hacking sub-forum, i can say it's not going to happen anytime soon. I read a lot of post over there that says you need access to the Secure Element which is not going to happen(at least now)

OK well thank you for the answer. that is unfortunate. It seemed a nice addition to the phone's capabilities.
Jim

Should be possible on 4.4
I believe android 4.4 should allow this now:
developer.android.com/guide/topics/connectivity/nfc/hce.html
Unfortunately I've not seen an implementation yet

[Q] HTC One X NFC Reader/Writer

Hi XDA,
I'd like to confirm with you guys if you already tested HTC One X NFC to write on tags? Reading should not be an issue. What tag types can you recommend on writing using One X's NFC?
Thanks,
Skidz

I bought a starter pack of tags from rapidnfc which included a variety of different size sticker tags, a wrist band and a key chain fob.
I have written a few tags to test them out but only have 1 that I'm using in a real world situation (stuck to my laptop so I scan it turns my phone into a wifi hotspots which my laptop then connects to.
Sent from my ARHD powered HOX

I read and wrote some 1K and 4K cards and tags and also read an E-Passport (image, data...), no problems.
I also ordered a started pack from rapidnfc looking forwards to some stickers...

NFC Writing
tehdomil said:
I bought a starter pack of tags from rapidnfc which included a variety of different size sticker tags, a wrist band and a key chain fob.
I have written a few tags to test them out but only have 1 that I'm using in a real world situation (stuck to my laptop so I scan it turns my phone into a wifi hotspots which my laptop then connects to.
Sent from my ARHD powered HOX
Click to expand...
Click to collapse
Thanks for the info. How's the writing time? and what app did you use for writing?

NFC Tag Writer
zvieratko said:
I read and wrote some 1K and 4K cards and tags and also read an E-Passport (image, data...), no problems.
I also ordered a started pack from rapidnfc looking forwards to some stickers...
Click to expand...
Click to collapse
Hi,
Which e-passport are you referring? Are the cards and tags rewritable also?
Thanks

skidz13 said:
Hi,
Which e-passport are you referring? Are the cards and tags rewritable also?
Thanks
Click to expand...
Click to collapse
Czech passport with biometry - I think all new European passports (can) have RFID inside. All that was needed to read it was to provide passport number, date of birth and expiration date, and it decrypted the passport and displayed info (used NFC Taginfo app.)
Yes, when you buy blank cards they are rewritable, even some cards you get for access to buildings/garages, or loyalty cards are not locked and can be re-used (depends on how serious they were about security ).

anybody knows how the power usage is for NFC?
Is it a huge drain on the battery?
a friend of mine has some tags laying around and i'm picking them up next saturday.
Want to program a few tags for a couple of tasks
1) Disable BT and enable WiFi when i'm home
2) Disable WiFi and enable BT when i'm in the car
3) Start NAV when i dock my phone in my car mount
4) Disable WiFi and BT when i'm @ work

HOX NFC Topic
zvieratko said:
Czech passport with biometry - I think all new European passports (can) have RFID inside. All that was needed to read it was to provide passport number, date of birth and expiration date, and it decrypted the passport and displayed info (used NFC Taginfo app.)
Yes, when you buy blank cards they are rewritable, even some cards you get for access to buildings/garages, or loyalty cards are not locked and can be re-used (depends on how serious they were about security ).
Click to expand...
Click to collapse
I should try on my passport also using NFC Taginfo. By the way, I'm using farebot to read my mrt card info, how can I use the info itself to be written on different card?
Thanks

NFC Power
tmaniac said:
anybody knows how the power usage is for NFC?
Is it a huge drain on the battery?
a friend of mine has some tags laying around and i'm picking them up next saturday.
Want to program a few tags for a couple of tasks
1) Disable BT and enable WiFi when i'm home
2) Disable WiFi and enable BT when i'm in the car
3) Start NAV when i dock my phone in my car mount
4) Disable WiFi and BT when i'm @ work
Click to expand...
Click to collapse
I think, the power usage of NFC is not bad unlike GPS can drain faster. But if your really want to save battery, try to switch off 3G/Wifi/GPS, etc and decrease the brightness.

skidz13 said:
I should try on my passport also using NFC Taginfo. By the way, I'm using farebot to read my mrt card info, how can I use the info itself to be written on different card?
Thanks
Click to expand...
Click to collapse
You can't just clone a passport, not possible. It is like a smartcard - you ask it for data, provide some password, and it gives you the data. You don't just "read" it.

zvieratko said:
You can't just clone a passport, not possible. It is like a smartcard - you ask it for data, provide some password, and it gives you the data. You don't just "read" it.
Click to expand...
Click to collapse
I'm not referring on my passport but the mrt card which is NFC-readable. Is that possible?
Sent from my HTC One X using xda premium

skidz13 said:
I'm not referring on my passport but the mrt card which is NFC-readable. Is that possible?
Sent from my HTC One X using xda premium
Click to expand...
Click to collapse
mrt? what is that?
But the probable answer is no - altough you can read and write almost anything, security is usually also tied to the UID of the card, and you can't (usually ;-))) change that. Also, more secure cards don't allow themselves to be read completely - you can just increment/decrement some counter or make them ID themselves.

zvieratko said:
mrt? what is that?
But the probable answer is no - altough you can read and write almost anything, security is usually also tied to the UID of the card, and you can't (usually ;-))) change that. Also, more secure cards don't allow themselves to be read completely - you can just increment/decrement some counter or make them ID themselves.
Click to expand...
Click to collapse
Actually, mrt is a train service in my country. Their card is NFC supported and I'm able to read its data. What I want is if I can add extra data to the card or copy its data to another mrt card. Is overwriting possible without losing its current data?
Sent from my HTC One X using xda premium

lol you wanted to transfer the $ from 1 card to another?
hmm..~

HOX NFC
athenodorus said:
lol you wanted to transfer the $ from 1 card to another?
hmm..~
Click to expand...
Click to collapse
Not really, just want to try adding commands to my existing CEPAS card using NFC.

i have similar idea, so maybe will join this thread.
my thoughts are to clone travel card (to phone) and use phone instead of card (p.ex. to open gates in metro).
is it possible? i couldn't find any app on market

The problem with some actions like change wifi, etc, is the need to unlock the screen for all the actions.
I understand the security point of view, but if I need to unlock the screen, and touch it on a tag, is easier to click a shortcut on my home.
Does have any paramter, or rom that alows to use NFC without unlocking the screen ?

Farebot
skidz13 said:
I should try on my passport also using NFC Taginfo. By the way, I'm using farebot to read my mrt card info, how can I use the info itself to be written on different card?
Thanks
Click to expand...
Click to collapse
My farebot is not reading any details of my ezlink card from HTC One X.
Could you help me please

angusbrasil said:
The problem with some actions like change wifi, etc, is the need to unlock the screen for all the actions.
I understand the security point of view, but if I need to unlock the screen, and touch it on a tag, is easier to click a shortcut on my home.
Does have any paramter, or rom that alows to use NFC without unlocking the screen ?
Click to expand...
Click to collapse
[MOD] NFC on screenoff
Sent from my HTC One X using xda premium

tehdomil said:
I bought a starter pack of tags from rapidnfc which included a variety of different size sticker tags, a wrist band and a key chain fob.
I have written a few tags to test them out but only have 1 that I'm using in a real world situation (stuck to my laptop so I scan it turns my phone into a wifi hotspots which my laptop then connects to.
Sent from my ARHD powered HOX
Click to expand...
Click to collapse
Sorry in advance for the potentially daft question. I would like to do similar to what others have posted, ie a tag in the car to turn on BT and turn off WiFi etc. Will order some tags but don't know how to write them. Can the One X write to the tags using NFC ReTag or similar? If not whats the procedure?
Thanks all

How to use nfc to open rfid door lock

Hi all,
I have a Samsung EZON door lock. The lock has rfid and uses 13.56mhz tags. I'm trying to figure out if it's possible to use my S4 to unlock the door. Anyone have any thoughts or ideas about this? Any help or information would be appreciated.
TIA

Wouldn't you just need some kind of app to do it? If the frequency and protocol is correct (hardware is compatible), I would think you just need a way to transmit the data. I assume there are apps for that. It seems to me all you need is an app to "copy" the data from the key and transmit it when requested. However, I have no idea if there is security in preventing the copy, if there is a random code change at each interaction (like a garage door opener), etc.
Try checking the NFC tag reader/writer apps in the play store and see if any of them will read the tag with the phone hardware. That would be the first step I would think.

NFC war problem

I downloaded the app NFC war by radiowar and whenever I click on read a card
or war it tells me to touch a NFC tag but when I do nothing happens..
Could someone send me a tutorial for this app or explain to me how it works?

yonatansss said:
I downloaded the app NFC war by radiowar and whenever I click on read a card
or war it tells me to touch a NFC tag but when I do nothing happens..
Could someone send me a tutorial for this app or explain to me how it works?
Click to expand...
Click to collapse
Not sure about the specific app, but typically with NFC (RFID) make sure:
1. Your phone has NFC capability and is turned ON (yes, there have been people trying it without their phone supporting it!!!)
2. Make sure you know where the NFC antenna is on your phone and place the tag right on top of it
3. Maximum distance between the tag and your NFC antenna ~3cm. It might work at greater distance, but typically the shorter the better
4. Your NFC tag is working! If one does not work, try another one. Dead tags is not uncommon.
5. The application may not be compatible with your phone's NFC chip! In that case, the app will simply not work. Check with the developer regarding compatible handsets.

nfc
is this nfc an hardware, my phone doesn't have, can I get it with rom updates?

ztobs said:
is this nfc an hardware, my phone doesn't have, can I get it with rom updates?
Click to expand...
Click to collapse
Yes, NFC is hardware. If your phone doesn't have it then you're out of luck.

Might have figured this already but sometimes you need to leave the card on for between a minute and 30 seconds before it can read all the data