[NFC Hacking] dbennett428:
A couple questions...

I apologize if these have been answered, but what about MST (Magnetic Secure Transport; LoopPay Tech acquired and used by Samsung). While I know it was designed to transmit, I have read conflicting information regarding whether the tech built into new Samsung devices can read magnetic stripes as well. While I question the veracity of such claims, seeing as the card would need to be swiped directly over the sensor at a very short distance, there is a very sensitive magnetic field detector (plus the low power magnetic field detector used for gleaning cardinal direction) present in galaxy devices that I can confirm at least is able to register when a card is placed within proximity of the sensor- and since I could see Samsung placing tech to serve purpose for a built in "Square-like" payment system for possible future implementation, it makes me think that reading mag stripes may be possible too (although the tech would obviously be disabled/highly restricted with stock firmware, to prevent people from using their phone as a card stealing device. I've seen news articles stating that software modified "smart phones can read any credit card if placed against a wallet". Although we all know how the media has no idea what they're talking about when it comes to tech- so they may be referring to the ability to read NFC/contactless cards. Anyone have any info on this? Just curious.

**Question two (most important): Does anyone know how to "replay" captured cards, or custom NFC data? Does any app exist? I can read NFC cards and alter the data, then copy it back, or to other cards, but it seems the NFC will only send data when a card is detected. I want to be able to be able to copy an NFC card (more specifically the building entry card for my work which I often forget and need to wait outside for someone lol) and then use my phone to beam it into the reader. I always have my phone, so I'd never be locked out. The issue is, even though I can copy the card data to a new card with my device (it's an old Mifare system and actually unencrypted, simple code transfer), there's no way for me to get the phone to send the data when up against the scanner. I have tried a dozen apps, spent like $30 on pro versions, etc. I assume it's the same as sending the data as if transferring data to a new card, but since it doesn't recognize the sensor as a card, it won't activate NFC to send the data. I once placed a blank card between my phone and the sensor, and copied the data while quickly pulling the card, which seemed to work (although it may have been the card opening the door once it was made- I just was trying to figure out if the copy op was the same signal as a card being read (I'm assuming plus a header, but my thinking was that would be ignored by the reader.

So is there any way to get the NFC to playback data even when (for whatever reason) it doesn't detect anything to playback the data to?

IDK why the reader isn't recognized, but it isn't. But since the card is recognized, and copy ops work, I don't see why if the card data is replayed, the reader wouldn't pick it up. I just need to somehow replay it.

Also, any way to force the NFC to scan mode and log any raw data? That would be useful as well.

Thanks.