LFSRs are notoriously insecure from a cryptographic standpoint because the structure of an n-bit LFSR can be easily deduced by observing 2n consecutive bits. Owing to the good statistical properties, large period and low implementation costs, LFSR have achieved wide acceptance in developing stream ciphers. The Linear Shift Feedback Registers have always received considerable attention in cryptography. These are extremely useful to know when trying to crack Mifare RFID cards: Manufactures pre-load Mifare cards with default keys – these can be found within their design/specification documentation, below is a list of the most common default keys.
Sec 1 Block 3| Key A |Permissions | Key B Sec 0 Block 3| Key A |Permissions | Key B Sec 0 Block 2| Mifare Application Directory | R/W Sec 0 Block 1| Mifare Application Directory | R/W
Sec 0 Block 0| UID | Manufacturer Data | Read Only I am only demonstrating the first 2 Sectors, as Sector 1 layout is typically repeated right down to Sector 15 (Mifare 1K card): Sector Block | 16 Byte Data Field | Read/Write Technical Detailsīelow is a simplified depiction of the layout of a Mifare RFID card. These cards are relativity cheap and cost approximately £1(GBP) each.
One of the most used RFID cards (13.56MHz), based on ISO14443 A/B standard and uses the proprietary crypto1 algorithm with 48bit keys. The organisations that tend to be vulnerable are early adopters of the technology, and in some cases departments that have a fixed limited security budget? Mifare Specification Overview RFID is our future, and unless implemented in a secure fashion – it to can be vulnerable to attack.īelow we will walk through a valid attack methodology, including hardware and software, that can be used to subvert some RFID Access Control Systems. Our previous posting on Access Control Part 1: Magstripes Revisited, demonstrated the use and subversion of magstripe technology.
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