CLRC632 Datasheet, PDF (79/163 Pages) NXP Semiconductors – Multiple Protocol Contactless Reader IC

Philips Semiconductors
Product Specification Rev. 3.0; May 2003
Multiple Protocol Contactless Reader IC
CL RC632
6.4.1 KEY FORMAT
To store a key in the E²PROM, it has to be written in a specific format. Each key byte has to be split into the
lower four bits k0 to k3 (lower nibble) and the higher four bits k4 to k7 (higher nibble). Each nibble is stored
twice in one byte and one of the two nibbles is bit-wise inverted. This format is a precondition for successful
execution of the LoadKeyE2- (see 18.9.1) and the LoadKey-Command (see 18.9.2).
With this format, 12 bytes of the E²PROM memory are needed to store a 6 byte long key.
This is shown in the following table:
Master Key Byte
0 (LSB)
1
Master Key Bits k7 k6 k5 k4 k7 k6 k5 k4 k3 k2 k1 k0 k3 k2 k1 k0 k7 k6 k5 k4 k7 k6 k5 k4 k3 k2 k1 k0 k3 k2 k1 k0
E²PROM Byte
Address
n
n+1
n+2
n+3
Example
5A_hex
F0_hex
5A_hex
E1_hex
Table 6-8: Key Storage Format
5 (MSB)
k7 k6 k5 k4 k7 k6 k5 k4 k3 k2 k1 k0 k3 k2 k1 k0
n+10
n+11
5A_hex
A5_hex
Example: For the actual key A0 A1 A2 A3 A4 A5_hex the value 5A F0 5A E1 5A D2 5A C3 5A B4 5A A5_hex
must be written into the E²PROM.
Note: Although it is possible to load data of any other format into the key storage location of the E²PROM, it
is not possible to obtain a valid card authentication with such a key. The LoadKeyE2-Command (see 18.9.1)
will fail.
6.4.2 STORAGE OF KEYS IN THE E²PROM
The CL RC632 reserves 384 bytes of memory area in the E²PROM to hold Crypto1 keys. It uses no memory
segmentation to mirror the 12 bytes structure of key storage. Thus, every byte of the dedicated memory area
may be the start of a key.
Example: If a key loading cycle starts at the last byte address of an E²PROM block, e.g. key byte 0 is stored
at 12F_hex, the following bytes are stored in the next E²PROM block , e.g. key byte 1 is stored at 130_hex, byte 2
at 131_hex, up to byte 11 at 13A_hex.
With 384 bytes of memory and 12 bytes needed for one key, 32 different keys may be stored in the
E²PROM.
Note: It is not possible to load a key exceeding the E²PROM byte location 1FF_hex.
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