It also comes with standalone functionality. It comes with a large command set for most things one might want to do with contactless cards. It consists of a USB reader with a fat firmware and a terminal client, which can be used to control the device. The Proxmark is probably the most used tool when doing RFID/NFC research. Also, using the CRYPTO1 algorithm, communication with the card is encrypted. Depending on the configuration (access bits) these keys are neccessary for reading and writing data on the cards. It is important to note, that byte 9 of the Sector Trailer may contain user data.Īs “containing keys” already implies, Mifare Classic cards offer certain protection for stored data. The data sets contains of 6 byte KEY A, 3 byte access bits, 1 byte user data and 6 byte KEY B. Block 3 of each sector can not be used for data (“Sector Trailer”) (except for byte 9), but contains the applicable access keys and access bits. Sector 0, Block 0 contains the UID (either 4 byte or 7 byte) and further manufacturer information. The mostly used Mifare Classic chips come with 1k of memory, which are split into 16 sectors, with 4 blocks each. The version covered on this page is Mifare Classic, which has a very bad history of being hacked, cracked and broken… Mifare Classic Protection here has to be applied on application layer and has to cover the risk of cloning the card. As such their read protection is just as good as the protection of a printed piece of paper. They don’t have any means of protection / encryption except for the optional write protection. Access control bits managing which parts of the user data may be written / changed.Each card has a 512-bit EEPROM which contains: The most simple version is Mifare Ultralight, which is often use in contactless room keys in hotels or for short time use tickets in public transport. If you’ve ever had an access card for hotel rooms, a contactless payment card for a canteen or even a modern bus ticket in your hand, you will have used one of the Mifare flavours. Mifare is a brand of chips for contactless smart cards made by NXP.

Cracking mifare ultralight