210 karma · joined January 22, 2020
Regarding PPS, the L76B does this cheaty thing where it actually sends the PPS signal over UART. They provide a calculation to go from “Time of first byte” to a regular PPS signal on the receiving side.
In a simple sense, NTAG cards can do NFC things, but MIFARE can do lots more (access control for example)..and also NFC things..somewhat.
Magic mifare refers to special cards that let you bypass the write-lock of genuine mifare cards. These are mostly used for cloning keys (either for red-team pentesting or for people who want a copy of an office key for whatever reason)
I've found the people over in the DT forum are pretty helpful with the cloning and usage aspect of things: https://forum.dangerousthings.com
Additionally, Iceman's Discord people has tons of smart people: https://discord.com/invite/iceman
Try wiping, then writing a URL from Android.
Then just tap to the iPhone and see if Safari opens or not. It shouldn't
I used this page as reference when I was putting together the "magic bytes" in the final section of the blog post: https://www.oreilly.com/library/view/beginning-nfc/978144932...
Something's clearly up there. You can see that even IOS and Android disagree with each other on what NDEF should look like by a few bytes. Very interesting.
Make a dump after doing "hf mf ndefformat".
Then make a dump after writing a payload from an iPhone. (since iPhone seems to want ndefformat anyways)
Then wipe again and make a dump after writing from Android.
If my Android phone wasn't dead, I'd love to compare an iPhone's write against the Android NFC Tools app's write.
If anyone else has an iPhone, an Android phone, and a Proxmark, I'd be interested in seeing a three-way diff between them all.
EDIT: I'm going to try to cross-post to the DT forum to see if anyone has ideas.
Gen 1, 1a, 3 and 4 all use special commands to unlock and edit block 0.
Gen 2 treats block 0 as always being r/w. This allows Android phones to directly write to it (but also makes it possible to lock the card).
In terms of pm3 commands, "auto" tries everything. You might also want to use "lf search" or "hf search" to only try one of your antennas and not the other.
The actual Magic part isn't really important here, since my phone doesn't even care about block 0. It just makes it easier to read and wipe the card when you have the extra command set at your disposal.
Here's the first 6 blocks of the card after I ran through the instructions of the post, then a ndefformat-only card (that never touched an iphone).
[=] 0 | 0 | 00 56 78 BB 95 08 04 00 02 B2 1E 24 23 27 1E 1D | .Vx........$#'.. [=] | 1 | 14 01 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 | ...�.�.�.�.�.�.� [=] | 2 | 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 | .�.�.�.�.�.�.�.� [=] | 3 | A0 A1 A2 A3 A4 A5 78 77 88 C1 89 EC A9 7F 8C 2A | ......xw.......* [=] 1 | 4 | 00 00 03 12 D1 01 0E 55 04 65 77 70 72 61 74 74 | ....�..U.ewpratt [=] | 5 | 65 6E 2E 63 6F 6D FE 00 00 00 00 00 00 00 00 00 | en.com�.........
[=] 0 | 0 | 00 56 78 BB 95 08 04 00 02 B2 1E 24 23 27 1E 1D | .Vx........$#'.. [=] | 1 | 14 01 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 | ...�.�.�.�.�.�.� [=] | 2 | 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 03 E1 | .�.�.�.�.�.�.�.� [=] | 3 | A0 A1 A2 A3 A4 A5 78 77 88 C1 89 EC A9 7F 8C 2A | ......xw.......* [=] 1 | 4 | 03 00 FE 00 00 00 00 00 00 00 00 00 00 00 00 00 | ..�............. [=] | 5 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ................
Going to look further at the actual data in the first 3 blocks momentarily.
..yes.
Hopefully getting that installed later this week :)
This is one of those cases where I know I really should investigate further, but I'm taking this one step at a time. Perhaps digging in to the "why" will become a follow-up post
I'm personally not a huge fan of needing to use NFC tags in the real world (parking meters use them for payment around here), but I do like creating tags.
I actually have a hotel keycard taped to my washing machine to do some laundry-based automation with my phone. Maybe I should write about that sometime..
I raised the linked issue internally with the team, and they have reason to suspect this has already been addressed.
That being said, if you (or anyone else here) are still seeing this issue occur, please raise a ticket with our support team (https://developers.cloudflare.com/support/contacting-cloudfl...) so we can investigate further.
Thanks :)
I think in some places you can set up a repeater for GMRS? You'd have to check up with the local regulations.
Of course, you could get everyone (or a few designated people) ham licensed. In many areas, operators are allowed to let other people use their radios under their supervision, so you might not need to even get every single person licensed.
Frequency plays a very big role, and the rest "depend".
There are some frequencies that'd just simply be impossible to use for communication that close (in the grand scheme of things) and others that would struggle to penetrate the trees.
Without knowing the area, I'd guess that 2 or 6 meters would be your best bet. (Probably 2m)
Your next challenge would be getting good antennas. The antenna matters a lot (even more than power output. (See me hitting Australia with 7w))
I'm always available for questions via email. You'll find it in my website.
The other comment under yours does a great job explaining things too.
As an additional note KC (Kilo Cycles) is the old way of writing Kilohertz. I just happen to prefer writing Kc for some reason even though I know it's no longer "correct"
The noise here is really bad due to my area and the construction of the building I live in. Much creativity is required to get QSOs from here.