MDEV-433-HH-LR8-HS Linx Technologies Inc, MDEV-433-HH-LR8-HS Datasheet - Page 3

• Manufacturer Part Number: MDEV-433-HH-LR8-HS
• Description: KIT DEV TX 433MHZ HS LONG-RANGE
• Manufacturer: Linx Technologies Inc
• Type: Transmitterr

Specifications of MDEV-433-HH-LR8-HS

• Frequency: 433MHz
• Product: RF Development Tools
• Maximum Frequency: 433.92 MHz
• Supply Voltage (max): 9 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Linx OEM Module
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

SECURITY OVERVIEW
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The HS Long-Range Handheld transmitter uses the HS
Series encoder, which is based on CipherLinx™
technology. CipherLinx™ is a high-security encryption
algorithm and wireless protocol designed for remote
control and remote keyless entry applications. It
provides a much greater level of security and many
more features than older technologies on the market,
such as fixed address or “rolling code” systems.
Additionally, the CipherLinx™ transmission protocol is much more advanced
than the simple PWM method employed by many systems. By utilizing an
advanced serial protocol for data, CipherLinx™ is able to offer superior noise
immunity, greater range, and increased link reliability, all of which are key factors
in a wireless system.
CipherLinx™ never sends or accepts the same data twice, never loses sync, and
changes codes with every packet, not just every button press. CipherLinx™
encryption is based on the Skipjack cipher developed by the U.S. National
Security Agency (NSA), and is widely considered one of the most secure ciphers
available. There have been no known successful attacks on the full Skipjack
algorithm. Skipjack is a block cipher that has 80-bit keys and 64-bit data blocks.
Since each packet is longer that 64 bits, Skipjack is employed in an encryption
mode. The particular encryption mode chosen for CipherLinx™ is based on the
CMC encryption mode, so that the resulting cipher is a special kind of function
known as a “strong PRP” (sPRP). The encryption mode uses several invocations
of Skipjack to encrypt the 128 bits in each message.
The Skipjack algorithm used by Linx has been proven secure and is not modified
to avoid any compromise of strength. CipherLinx™ is far more than just a
Skipjack implementation. CipherLinx's patent-pending technology combines
multiple calls to the encryption algorithm with a proprietary mixing algorithm.
CipherLinx™encryption, as implemented in the Linx HS Series, has been
independently evaluated by Independent Security Evaluators (ISE), a respected
security firm that is widely recognized for its expertise in electronic security. They
concluded that “the CipherLinx(™) protocol in the HS Series is well-designed
and is an excellent choice for applications requiring a secure unidirectional link.”
ISE’s full evaluation report can be found at www.cipherlinx.com. In summary,
CipherLinx™ is a powerful, independently verified, secure encryption technology
that is well-suited to a wide range of applications.
In addition to this high level of security, CipherLinx™ also offers a number of
features that are unique among remote control products. These include a large
number of data lines, internal key generation, “button level” control permissions,
an optional encoder PIN, as well as the ability for the decoder to identify the
originating encoder. Please refer to the HS Series encoder and decoder data
guides for full details.
Technology
CipherLinx
TM
TYPICAL SYSTEM SETUP
1. Create and exchange a key from the decoder development board
2. Establish Control Permissions
The HS Series Long-Range Handheld Transmitter is intended to make user
setup straightforward while ensuring the highest possible security. Its inherent
ease of use can be illustrated by a typical user setup. The Typical Applications
section of the HS Series Decoder Data Guide shows the circuit schematics on
which the receiver examples are based.
The handheld transmitter includes an on-
board infrared receiver designed to receive
the decoder’s key transmission. Sending
the key in this manner preserves security
while avoiding the need for a hardwire
connection.
The high-security key is created and
exchanged by placing the decoder in the
Create
MODE_IND LED will light to indicate that
the decoder has entered Create Key
Mode. The decoder’s CREATE_KEY
button is then pressed ten times to create
the key. This ensures that the key is random and chosen from among all 2
possible keys. After the tenth press, the MODE_IND LED will turn off and the
decoder will output the key via a 900nm infrared diode on the KEY_OUT line. A
paper clip is used to press the GET_KEY button on the back of the transmitter.
The back of the transmitter is held near the decoder’s infrared diode within
twenty seconds. Once the key has been transferred, the MODE_IND LEDs on
the transmitter and decoder development board illuminate to indicate success.
The user or manufacturer may also set “button level” Control Permissions.
Control Permissions determine which buttons on the transmitter will be
acknowledged by the decoder. Permission settings are established during set-
up, and retained in the decoder’s non-volatile memory. The HS Series Control
Permissions allow each transmitter in a system to activate different data lines.
This is especially useful in applications where differing user access or activation
capabilities are desired.
Consider this practical example: a three-door garage houses Dad’s Corvette,
Mom’s Mercedes, and Son’s Yugo. With most competitive products, any user’s
keyfob could open any garage door as long as the addresses match. In an HS-
based system, the keyfobs could easily be configured to open only certain doors
(guess which one Son gets to open!).
Setting the control permissions is intuitive. The user presses the decoder’s
LEARN button. The decoder’s MODE_IND LED will start flashing and the user
simply presses the handheld transmitter buttons that will be recognized. Control
Permissions are stored when the LEARN button is pressed again or
automatically after seventeen seconds.
There are other powerful options, such as programming a user PIN or copying a
decoder, but these two steps are all that is required for a typical setup.
Key
Mode.
The
decoder’s
Figure 2: Button Access Holes
MODE_IND
Window
GET_KEY Button
CREATE_PIN
Button
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