Access bits of Mifare 1K NFC cards

Question

Mifare (S50) 1K NFC cards have 16 sectors, each sector has 4 blocks and each block holds 16 bytes of data.

Each sector's last block is the Sector Trailer where the KeyA and KeyB are specified with the access bits that are used to authenticate the sector: Sector trailer: KeyA(6bytes) + Access Bits (4bytes) + KeyB (6bytes).

I am trying to read and write these cards but I cannot figure out what the access bits should be for the sector trailer if I want KeyA to have Read permission only and KeyB to have Read AND Write permissions.

Answer 1

In order to achieve the above you have to set the Access bits to the following:

78 77 88 00

There is a great app called MifareWnd that allows you to create costume Access bits by specifying the permissions in the program.

Here is the link to the free mifareWnd: http://philips-semiconductors-mifarewnd.software.informer.com/1.7/