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Mifare Classic & iOS

Reading

Mifare Classic IC info and block data cannot be read via iOS, This is because Mifare Classics do not conform to the NFC Forum specification for NFC, Therefore only NFC R/W chips made by NXP can communicate with Mifare Classic. The NFC R/W chip in iPhones isnt made by NXP and therefore can't communicate with Mifare Classics.

Writing

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Guide on how to make your own Digital Business Card NFC Tag

You may have seen products like popl popping up over the last few years, they're classy, sophisticated and impressive, but in reality these products are not doing anything earth shattering. You can very easily make multiple of your own for less than 10$ total.

What you'll need

1. NTAG216 as either Stickers, Fobs, Cards. Dealers choice you can find these on amazon for very cheap*
2. A Phone capable of reading and writing nfc (most modern smart phones are capable of this but check first)
3. The NFCTools app. Android link | Apple link
4. A Free social media sharing platform such as linktree or Carrd

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Mifare Classic - SAK Swapping Explained

What is SAK Swapping

Behaviour has been observered where some system using Mifare Classic credentials will identify with one SAK (0x08/18) on a basic search (Wake up) but when the block 0 is dumped, the SAK appears to be different (0x88)

This is because the SAK reported on a Wake up is not coming from Block 0 but is instead burned into the card, The SAK in Block 0 is merely a Vanity SAK.

If the dump is loaded onto a Magic Mifare Classic that Mirrors the vanity SAK as the actual SAK on Wake up it will tell the system that the credential is a duplicate & to deny access.

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Calculating BCC by xoring

BCC calc in simplicity is just xoring the uid byte by byte starting from 0, and using the outputted xor from the first byte for the second byte so on and so forth

xor-ing is lining up the binary and if the number above and below are the same, value is 0 and if theyre different its 1

0000 0000
0000 0001 = 01
0000 0001 XOR = 0000 0001 = 01

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Keybase proof

I hereby claim:

• I am equipter on github.
• I am equipterr (https://keybase.io/equipterr) on keybase.
• I have a public key ASCObetljGFM2GzoGGplraXsLjMauhR7P7tvGrDhk7slJAo

To claim this, I am signing this object: