Custom Hardware Attack
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cryptography Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adve ...
, a custom hardware attack uses specifically designed
application-specific integrated circuit An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-effici ...
s (ASIC) to decipher encrypted messages. Mounting a cryptographic
brute force attack In cryptography, a brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the corr ...
requires a large number of similar computations: typically trying one key, checking if the resulting decryption gives a meaningful answer, and then trying the next key if it does not. Computers can perform these calculations at a rate of millions per second, and thousands of computers can be harnessed together in a
distributed computing A distributed system is a system whose components are located on different networked computers, which communicate and coordinate their actions by passing messages to one another from any system. Distributed computing is a field of computer sci ...
network. But the number of computations required on average grows exponentially with the size of the key, and for many problems standard computers are not fast enough. On the other hand, many cryptographic algorithms lend themselves to fast implementation in hardware, i.e. networks of
logic circuit A logic gate is an idealized or physical device implementing a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate ...
s, also known as gates. Integrated circuits (ICs) are constructed of these gates and often can execute cryptographic algorithms hundreds of times faster than a general purpose computer. Each IC can contain large numbers of gates (hundreds of millions in 2005). Thus the same decryption circuit, or cell, can be replicated thousands of times on one IC. The communications requirements for these ICs are very simple. Each must be initially loaded with a starting point in the key space and, in some situations, with a comparison test value (see known plaintext attack). Output consists of a signal that the IC has found an answer and the successful key. Since ICs lend themselves to mass production, thousands or even millions of ICs can be applied to a single problem. The ICs themselves can be mounted in
printed circuit board A printed circuit board (PCB; also printed wiring board or PWB) is a medium used in electrical and electronic engineering to connect electronic components to one another in a controlled manner. It takes the form of a laminated sandwich str ...
s. A standard board design can be used for different problems since the communication requirements for the chips are the same. Wafer-scale integration is another possibility. The primary limitations on this method are the cost of chip design, IC fabrication, floor space, electric power and thermal dissipation. An alternative approach is to use FPGAs (
field-programmable gate array A field-programmable gate array (FPGA) is an integrated circuit designed to be configured by a customer or a designer after manufacturinghence the term '' field-programmable''. The FPGA configuration is generally specified using a hardware ...
s); these are slower and more expensive per gate, but can be reprogrammed for different problems
COPACOBANA
(Cost-Optimized Parallel COde Breaker) is one such machine, consisting of 120 FPGAs of type
Xilinx Xilinx, Inc. ( ) was an American technology and semiconductor company that primarily supplied programmable logic devices. The company was known for inventing the first commercially viable field-programmable gate array (FPGA) and creating the fi ...
Spartan3-1000 which run in parallel.


History

The earliest custom hardware attack may have been the
Bombe The bombe () was an electro-mechanical device used by British cryptologists to help decipher German Enigma-machine-encrypted secret messages during World War II. The US Navy and US Army later produced their own machines to the same functiona ...
used to recover Enigma machine keys in
World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
. In 1998, a custom hardware attack was mounted against the
Data Encryption Standard The Data Encryption Standard (DES ) is a symmetric-key algorithm for the encryption of digital data. Although its short key length of 56 bits makes it too insecure for modern applications, it has been highly influential in the advancement of cr ...
cipher by the
Electronic Frontier Foundation The Electronic Frontier Foundation (EFF) is an international non-profit digital rights group based in San Francisco, California. The foundation was formed on 10 July 1990 by John Gilmore, John Perry Barlow and Mitch Kapor to promote Internet ...
. Their " Deep Crack" machine cost U.S. $250,000 to build and decrypted the DES Challenge II-2 test message after 56 hours of work. The only other confirmed DES cracker was th
COPACOBANA
machine (Cost-Optimized PArallel COde Breaker) built in 2006. Unlike Deep Crack, COPACOBANA consists of commercially available FPGAs (reconfigurable logic gates). COPACOBANA costs about $10,000 to build and will recover a DES key in under 6.4 days on average. The cost decrease by roughly a factor of 25 over the EFF machine is an impressive example for the continuous improvement of digital hardware. Adjusting for inflation over 8 years yields an even higher improvement of about 30x. Since 2007, SciEngines GmbH, a spin-off company of the two project partners of COPACOBANA has enhanced and developed successors of COPACOBANA. In 2008 their COPACOBANA RIVYERA reduced the time to break DES to the current record of less than one day, using 128 Spartan-3 5000's.Break DES in less than a single day
ress release of firm, demonstrated at a 2009 workshop/ref> It is generally believed that large government code breaking organizations, such as the U.S.
National Security Agency The National Security Agency (NSA) is a national-level intelligence agency of the United States Department of Defense, under the authority of the Director of National Intelligence (DNI). The NSA is responsible for global monitoring, collectio ...
, make extensive use of custom hardware attacks, but no examples have been
declassified Declassification is the process of ceasing a protective Classified information, classification, often under the principle of freedom of information. Procedures for declassification vary by country. Papers may be withheld without being classif ...
.


See also

* TWIRL *
TWINKLE Twinkle may refer to: * Twinkling, the variation of brightness of distant objects People * Twinkle (singer) (1948–2015), born Lynn Annette Ripley, English singer-songwriter * Twinkle Khanna, Indian movie actress * Twinkle Bajpai, female conte ...


References


External links


COPACOBANA, Cost Optimized Code Breaker and Analyzer


{{Hardware acceleration Cryptographic attacks Hardware acceleration