
CLRC632_35
NXP B.V. 2009. All rights reserved.
Product data sheet
PUBLIC
Rev. 3.5 — 10 November 2009
073935
42 of 126
NXP Semiconductors
CLRC632
Multiple protocol contactless reader IC (MIFARE/I-CODE1)
9.14 MIFARE authentication and Crypto1
The security algorithm used in the MIFARE products is called Crypto1. It is based on a
proprietary stream cipher with a 48-bit key length. To access data on MIFARE cards,
knowledge of the key format is needed. The correct key must be available in the CLRC632
to enable successful card authentication and access to the card’s data stored in the
EEPROM.
After a card is selected as dened in ISO/IEC 14443 A standard, the user can continue
with the MIFARE protocol. It is mandatory that card authentication is performed.
Crypto1 authentication is a 3-pass authentication which is automatically performed when
During the card authentication procedure, the security algorithm is initialized. After a
successful authentication, communication with the MIFARE card is encrypted.
9.14.1 Crypto1 key handling
On execution of the authentication command, the CLRC632 reads the key from the key
buffer. The key is always read from the key buffer and ensures Crypto1 authentication
commands do not require addressing of a key. The user must ensure the correct key is
prepared in the key buffer before triggering card authentication.
The key buffer can be loaded from:
Fig 15. Crypto1 key handling block diagram
001aak624
FIFO BUFFER
from the microcontroller
WriteE2
LoadKey
EEPROM
KEYS
KEY BUFFER
LoadKeyE2
during
Authent1
CRYPTO1
MODULE
serial data stream out
serial data stream in
(plain)
(encrypted)