HCS410/WM Microchip Technology, HCS410/WM Datasheet - Page 2

• Manufacturer Part Number: HCS410/WM
• Description: IC CODE HOPPING ENCODER SMD
• Manufacturer: Microchip Technology
• Series: KEELOQ®r
• Type: Code Hopping Encoder and Transponderr

Specifications of HCS410/WM

• Applications: Access Control Systems
• Package / Case: *
• Lead Free Status / RoHS Status: Request inventory verification / Request inventory verification
• Mounting Type: -

HCS410/WM
1.0
1.1
• Anticollision – Allows multiple transponders to be
• Encoder Key – A unique 64-bit key generated and
• IFF – Identify friend or foe is a means of validating
• K
• Learn – The HCS product family facilitates sev-
• Manufacturer’s Code – A 64-bit word, unique to
• Transport Code – A 32-bit transport code needs to
FIGURE 1-1:
DS41116B-page 2
in the magnetic field simultaneously and be veri-
fied individually.
programmed into the encoder during the manu-
facturing process. The encoder keycontrols the
encryption algorithm and is stored in EEPROM on
the transponder device.
a token. A decoder sends a random challenge to
the token and checks that the response of the
token is a valid response.
level of the HCS410/WM is based on the patented
K
algorithm based on a block length of 32 bits and a
key length of 64 bits is used. The algorithm
obscures the information in such a way that even
if the unencrypted/challenge information differs by
only one bit from the information in the previous
challenge, the next coded response will be totally
different. Statistically, if only one bit in the 32-bit
string of information changes, approximately
50 percent of the coded transmission will change.
eral learning strategies to be implemented on the
decoder.
each manufacturer, used to produce a unique
encoder key in each transmitter (encoder).
be given before the HCS410/WM can be induc-
tively programmed. This prevents accidental
programming of the HCS410.
EE
EE
L
L
OQ
OQ
SYSTEM OVERVIEW
Key Terms
Encryption Algorithm – The high security
technology. A block cipher encryption
BASIC OPERATION OF AN IFF TOKEN
EEPROM Array
Serial Number
IFF Key
Challenge Received from Decoder
Preliminary
Algorithm
K
EE
IFF
L
OQ
1.2
The HCS410/WM is an IFF transponder for verification
of a token. In IFF mode the HCS410/WM is ideally
suited for authentication of a key before disarming a
vehicle immobilizer. Once the key has been inserted in
the car’s ignition the decoder would inductively poll the
key, validating it before disarming the immobilizer.
IFF validation of the token involves a random challenge
being sent by a decoder to a token. The token then
generates a response to the challenge and sends this
response to the decoder (Figure 1-1). The decoder cal-
culates an expected response using the same chal-
lenge. The expected response is compared to the
response received from the token. If the responses
match, the token is identified as a valid token and the
decoder can take appropriate action.
The HCS410/WM can do either 16 or 32-bit IFF. The
HCS410/WM has two encryption algorithms that can
be used to generate a response to a challenge. In addi-
tion there are up to two encoder keys that can be used
by the HCS410/WM. Typically each HCS410/WM will
be programmed with a unique encoder key(s).
In IFF mode, the HCS410/WM will wait for a command
from the base station and respond to the command.
The command can either request a read/write from
user EEPROM or an IFF challenge response. A given
16 or 32-bit challenge will produce a unique 16/32-bit
response, based on the IFF key and IFF algorithm
used.
K
EE
L
OQ
Serial Number
IFF
Read by Decoder
2001 Microchip Technology Inc.
Response