CLRC63201TSLASH0FE datasheet(137/163 Pages) PHILIPS

137 / 163 page

Philips Semiconductors

Product Specification Rev. 3.0; May 2003

Multiple Protocol Contactless Reader IC

CL RC632

137

Confidential

19 MIFARE CLASSIC AUTHENTICATION AND CRYPTO1

19.1 General

The security algorithm implemented in MIFARE Classic products is called Crypto1. It is based on a

proprietary stream cipher with a key length of 48 bits. To access data of a MIFARE Classic card, the

knowledge of the according key is necessary. For successful card authentication and subsequent access to

the card’s data stored in the EEPROM, the correct key has to be available in the CL RC632. After a card is

selected as defined in ISO14443A the user may continue with the MIFARE Classic protocol. In this case it

is mandatory to perform a card authentication. The Crypto1 authentication is a 3-pass authentication. This

procedure is done automatically with the execution of Authent1- (see 18.9.3) and the Authent2-Commands

(see 18.9.4). During the card authentication procedure, the security algorithm is initialised. The

communication with a MIFARE Classic card following a successful authentication is encrypted.

19.2 Crypto1 Key Handling

During the authentication command the CL RC632 reads the key from the internal key buffer. The key is

always taken from the key buffer. Therefore, the commands for Crypto1 authentication do not require

addressing of a key. The user has to ensure, that the correct key is prepared in the key buffer before the

card authentication is triggered.

The key buffer can be loaded

•

from the E²PROM with the LoadKeyE2-Command (see 18.9.1)

•

directly from the µ-Processor via the FIFO-Buffer with the LoadKey-Command (see 18.9.2)

This is shown in the following figure:

FIFO

E²PROM:

Keys

Key Buffer

Crypto1 Module

WriteE2

Serial Data Stream In

(Plain)

Serial Data Stream Out

(Encrypted)

During

Authent1

From the

µController

LoadKey

LoadKeyE2

Figure 19-1: Key Handling: Block Diagram

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