User's Manual

ACR1281U

 Advanced Card Systems Ltd. Page 61 of 81

The authentication has to be performed in two steps. The first step is to send the Authentication

Certificate to the card. The second step is to get back two bytes of authentication data calculated

by the card.

• Step 1: Send Authentication Certificate to the Card

• Command format

Pseudo-APDU

MEM_L

CODE CLA INS P1 P2

KEY

CLK_CNT Byte1 Byte 2 …… Byte 5 Byte 6

KEY Key to be used for the computation of the authentication certificate:

00 : key 1 with no cipher block chaining

01 : key 2 with no cipher block chaining

80 : key 1 with cipher block chaining (SLE5536 and SLE6636 only)

81 : key 2 with cipher block chaining (SLE5536 and SLE6636 only)

CLK_CNT Number of CLK pulses to be supplied to the card for the computation of each bit of the

authentication certificate. Typical value is 160 clocks (A0)

BYTE 1...6 Card challenge data

• Response data format

SW1 SW2

• SW1, SW2 = 61 02 if no error, meaning two bytes of authentication data are ready.

The authentication data can be retrieved by “Get_Response” command.

• Step 2: Get back the Authentication Data (Get_Response)

• Command format

Pseudo-APDU

CLA INS P1 P2 MEM_L

• Response data format

CERT SW1 SW2

CERT 16 bits of authentication data computed by the card. The LSB of BYTE 1 is

the first authentication bit read from the card.

• SW1, SW2 = 90 00 if no error