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Security Overview
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(
TM
) 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.linxtechnologies.com. In summary,
CipherLinx™ is a powerful, independently verified, secure encryption
technology that is well-suited to a wide range of applications.
CipherLinx
Technology
®
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.
Figure 4: CipherLinx Logo
