A5/1 is a stream cipher used to provide over-the-air communication privacy in the GSM cellular telephone standard. It is one of seven algorithms, it was kept secret, but became public knowledge through leaks and reverse engineering. A number of serious weaknesses in the cipher have been identified. A5/1 is used in the United States. A5/2 was a deliberate weakening of the algorithm for certain export regions. A5/1 was developed in 1987, when GSM was not yet considered for use outside Europe, A5/2 was developed in 1989. Though both were kept secret, the general design was leaked in 1994 and the algorithms were reverse engineered in 1999 by Marc Briceno from a GSM telephone. In 2000, around 130 million GSM customers relied on A5/1 to protect the confidentiality of their voice communications. Security researcher Ross Anderson reported in 1994 that "there was a terrific row between the NATO signal intelligence agencies in the mid-1980s over whether GSM encryption should be strong or not; the Germans said as they shared a long border with the Warsaw Pact.
A GSM transmission is organised as sequences of bursts. In a typical channel and in one direction, one burst is sent every 4.615 milliseconds and contains 114 bits available for information. A5/1 is used to produce for each burst a 114 bit sequence of keystream, XORed with the 114 bits prior to modulation. A5/1 is initialised using a 64-bit key together with a publicly known 22-bit frame number. Older fielded GSM implementations using Comp128v1 for key generation, had 10 of the key bits fixed at zero, resulting in an effective key length of 54 bits; this weakness was rectified with the introduction of Comp128v3. When operating in GPRS / EDGE mode, higher bandwidth radio modulation allows for larger 348 bits frames, A5/3 is used in a stream cipher mode to maintain confidentiality. A5/1 is based around a combination of three linear feedback shift registers with irregular clocking; the three shift registers are specified as follows: The bits are indexed with the least significant bit as 0. The registers are clocked in a stop/go fashion using a majority rule.
Each register has an associated clocking bit. At each cycle, the clocking bit of all three registers is examined and the majority bit is determined. A register is clocked. Hence at each step at least two or three registers are clocked, each register steps with probability 3/4; the registers are set to zero. For 64 cycles, the 64-bit secret key is mixed in according to the following scheme: in cycle 0 ≤ i < 64, the ith key bit is added to the least significant bit of each register using XOR — R = R ⊕ K. Each register is clocked; the 22-bits of the frame number are added in 22 cycles. The entire system is clocked using the normal majority clocking mechanism for 100 cycles, with the output discarded. After this is completed, the cipher is ready to produce two 114 bit sequences of output keystream, first 114 for downlink, last 114 for uplink. A number of attacks on A5/1 have been published, the American National Security Agency is able to decrypt A5/1 messages according to released internal documents.
Some attacks require an expensive preprocessing stage after which the cipher can be broken in minutes or seconds. Until the weaknesses have been passive attacks using the known plaintext assumption. In 2003, more serious weaknesses were identified which can be exploited in the ciphertext-only scenario, or by an active attacker. In 2006 Elad Barkan, Eli Biham and Nathan Keller demonstrated attacks against A5/1, A5/3, or GPRS that allow attackers to tap GSM mobile phone conversations and decrypt them either in real-time, or at any time. According to professor Jan Arild Audestad, at the standardization process which started in 1982, A5/1 was proposed to have a key length of 128 bits. At that time, 128 bits was projected to be secure for at least 15 years, it is now believed that 128 bits would in fact still be secure until the advent of quantum computing. Audestad, Peter van der Arend, Thomas Haug says that the British insisted on weaker encryption, with Haug saying he was told by the British delegate that this was to allow the British secret service to eavesdrop more easily.
The British proposed a key length of 48 bits, while the West Germans wanted stronger encryption to protect against East German spying, so the compromise became a key length of 54 bits. The first attack on the A5/1 was proposed by Ross Anderson in 1994. Anderson's basic idea was to guess the complete content of the registers R1 and R2 and about half of the register R3. In this way the clocking of all three registers is determined and the second half of R3 can be computed. In 1997, Golic presented an attack based on solving sets of linear equations which has a time complexity of 240.16. In 2000, Alex Biryukov, Adi Shamir and David Wagner showed that A5/1 can be cryptanalysed in real time using a time-memory tradeoff attack, based on earlier work by Jovan Golic. One tradeoff allows an attacker to reconstruct the key in one second from two minutes of known plaintext or in several minutes from two seconds of known plain text, but he must first complete an expen
Santa Barbara, California
Santa Barbara is the county seat of Santa Barbara County in the U. S. state of California. Situated on a south-facing section of coastline, the longest such section on the West Coast of the United States, the city lies between the steeply rising Santa Ynez Mountains and the Pacific Ocean. Santa Barbara's climate is described as Mediterranean, the city has been promoted as the "American Riviera"; as of 2014, the city had an estimated population of 91,196, up from 88,410 in 2010, making it the second most populous city in the county after Santa Maria. The contiguous urban area, which includes the cities of Goleta and Carpinteria, along with the unincorporated regions of Isla Vista, Mission Canyon, Hope Ranch and others, has an approximate population of 220,000; the population of the entire county in 2010 was 423,895. In addition to being a popular tourist and resort destination, the city economy includes a large service sector, technology, health care, agriculture and local government. In 2004, the service sector accounted for 35% of local employment.
Education in particular is well represented, with four institutions of higher learning on the south coast. The Santa Barbara Airport serves the city, Santa Barbara Aviation provides jet charter aircraft and train service is provided by Amtrak the Pacific Surfliner which runs from San Diego to San Luis Obispo). U. S. Highway 101 connects the Santa Barbara area with Los Angeles to the southeast and San Francisco to the northwest. Behind the city, in and beyond the Santa Ynez Mountains, is the Los Padres National Forest, which contains several remote wilderness areas. Channel Islands National Park and Channel Islands National Marine Sanctuary are located 20 miles offshore. Evidence of human habitation of the area begins at least 13,000 years ago. Evidence for a Paleoindian presence includes a fluted Clovis-like point found in the 1980s along the western Santa Barbara County coast, as well as the remains of Arlington Springs Man, found on Santa Rosa Island in the 1960s. An estimated 8,000 to 10,000 Chumash lived on the south coast of Santa Barbara County at the time of the first European explorations.
Five Chumash villages flourished in the area. The present-day area of Santa Barbara City College was the village of Mispu. Portuguese explorer João Cabrilho, sailing for the Kingdom of Spain, sailed through what is now called the Santa Barbara Channel in 1542, anchoring in the area. In 1602, Spanish maritime explorer Sebastián Vizcaíno gave the name "Santa Barbara" to the channel and to one of the Channel Islands. A land expedition led by Gaspar de Portolà visited around 1769, Franciscan missionary Juan Crespi, who accompanied the expedition, named a large native town "Laguna de la Concepcion". Cabrillo's earlier name, however, is the one; the first permanent European residents were Spanish missionaries and soldiers under Felipe de Neve, who came in 1782 to build the Presidio. They were sent both to fortify the region against expansion by other powers such as England and Russia, to convert the natives to Christianity. Many of the Spaniards brought their families with them, those formed the nucleus of the small town – at first just a cluster of adobes – that surrounded the Presidio of Santa Barbara.
The Santa Barbara Mission was established on the Feast of Saint Barbara, December 4, 1786. It was the tenth of the California Missions to be founded by the Spanish Franciscans, it was dedicated by Padre Fermín Lasuén, who succeeded Padre Junipero Serra as the second president and founder of the California Franciscan Mission Chain. The Mission fathers began the slow work of converting the native Chumash to Christianity, building a village for them on the Mission grounds; the Chumash laborers built a connection between the canyon creek and the Santa Barbara Mission water system through the use of a dam and an aqueduct. During the following decades, many of the natives died of diseases such as smallpox, against which they had no natural immunity; the most dramatic event of the Spanish period was the powerful 1812 earthquake, tsunami, with an estimated magnitude of 7.1, which destroyed the Mission as well as the rest of the town. The Mission was rebuilt by 1820 after the earthquake. Following the earthquake, the Mission fathers chose to rebuild in a grander manner, it is this construction that survives to the present day, the best-preserved of the California Missions, still functioning as an active church by the Franciscans.
After the Mexican government secularized the missions in the 1830s, the baptismal and burial records of other missions were transferred to Santa Barbara, now found in the Santa Barbara Mission Archive-Library. C-SPAN has produced a program on the mission archive-library; the Spanish period ended in 1822 with the end of the Mexican War of Independence, which terminated 300 years of colonial rule. The flag of Mexico went up the flagpole at the Presidio, but only for 24 years. Santa Barbara street names reflect this time period as well; the names de le Guerra and Carrillo come from citizens of the town of this time. They were instrumental in building up the town, so they were honored by having streets after them. After the forced secularization of the Missions in 1833
In computer science, a lookup table is an array that replaces runtime computation with a simpler array indexing operation. The savings in terms of processing time can be significant, since retrieving a value from memory is faster than undergoing an "expensive" computation or input/output operation; the tables may be precalculated and stored in static program storage, calculated as part of a program's initialization phase, or stored in hardware in application-specific platforms. Lookup tables are used extensively to validate input values by matching against a list of valid items in an array and, in some programming languages, may include pointer functions to process the matching input. FPGAs make extensive use of reconfigurable, hardware-implemented, lookup tables to provide programmable hardware functionality. Before the advent of computers, lookup tables of values were used to speed up hand calculations of complex functions, such as in trigonometry and statistical density functions. In ancient India, Aryabhata created one of the first sine tables, which he encoded in a Sanskrit-letter-based number system.
In 493 AD, Victorius of Aquitaine wrote a 98-column multiplication table which gave the product of every number from 2 to 50 times and the rows were "a list of numbers starting with one thousand, descending by hundreds to one hundred descending by tens to ten by ones to one, the fractions down to 1/144" Modern school children are taught to memorize "times tables" to avoid calculations of the most used numbers. Early in the history of computers, input/output operations were slow – in comparison to processor speeds of the time, it made sense to reduce expensive read operations by a form of manual caching by creating either static lookup tables or dynamic prefetched arrays to contain only the most occurring data items. Despite the introduction of systemwide caching that now automates this process, application level lookup tables can still improve performance for data items that if change. Lookup tables were one of the earliest functionalities implemented in computer spreadsheets, with the initial version of VisiCalc including a LOOKUP function among its original 20 functions.
This has been followed by subsequent spreadsheets, such as Microsoft Excel, complemented by specialized VLOOKUP and HLOOKUP functions to simplify lookup in a vertical or horizontal table. This is known as a linear search or brute-force search, each element being checked for equality in turn and the associated value, if any, used as a result of the search; this is the slowest search method unless occurring values occur early in the list. For a one-dimensional array or linked list, the lookup is to determine whether or not there is a match with an'input' data value. An example of a "divide and conquer algorithm", binary search involves each element being found by determining which half of the table a match may be found in and repeating until either success or failure; this is only possible if the list is sorted but gives good performance if the list is lengthy. For a trivial hash function lookup, the unsigned raw data value is used directly as an index to a one-dimensional table to extract a result.
For small ranges, this can be amongst the fastest lookup exceeding binary search speed with zero branches and executing in constant time. One discrete problem, expensive to solve on many computers is that of counting the number of bits which are set to 1 in a number, sometimes called the population function. For example, the decimal number "37" is "00100101" in binary, so it contains three bits that are set to binary "1". A simple example of C code, designed to count the 1 bits in a int, might look like this: This simple algorithm can take hundreds of cycles on a modern architecture, because it makes many branches in the loop - and branching is slow; this can be ameliorated using some other compiler optimizations. There is however a simple and much faster algorithmic solution - using a trivial hash function table lookup. Construct a static table, bits_set, with 256 entries giving the number of one bits set in each possible byte value. Use this table to find the number of ones in each byte of the integer using a trivial hash function lookup on each byte in turn, sum them.
This requires no branches, just four indexed memory accesses faster than the earlier code. The above source can be improved by'recasting"x' as a 4 byte unsigned char array and, coded in-line as a single statement instead of being a function. Note that this simple algorithm can be too slow now, because the original code might run faster from the cache of modern processors, lookup tables do not fit well in caches and can cause a slower access to memory. In data analysis applications, such as image processing, a lookup table is used to transform the input data into a more desirable output format. For example, a grayscale picture of the planet Saturn will be transformed into a color image to emphasize the differences in its rings. A classic example of reducing run-time computations using lookup tables is to obtain the result of a trigonometry calculation, such as the sine of a value. Calculating trigonometric functions can slow a computing application; the same application can finish much sooner when it firs
Bruce Schneier is an American cryptographer, computer security professional, privacy specialist and writer. Schneier is a fellow at the Berkman Center for Internet & Society at Harvard Law School, a program fellow at the New America Foundation's Open Technology Institute, he has been working for IBM since they acquired Resilient Systems where Schneier was CTO. He is the author of several books on computer security and cryptography. Schneier is a contributing writer for The Guardian news organization. Bruce Schneier is the son of a Brooklyn Supreme Court judge, he grew up in the Flatbush neighborhood of Brooklyn, New York, attending P. S. 139 and Hunter High School. After receiving a physics bachelor's degree from the University of Rochester in 1984, he went to American University in Washington, D. C. and got his master's degree in computer science in 1988. He was awarded an honorary Ph. D from the University of Westminster in London, England in November 2011; the award was made by the Department of Electronics and Computer Science in recognition of Schneier's'hard work and contribution to industry and public life'.
Schneier was a founder and chief technology officer of BT Managed Security Solutions Counterpane Internet Security, Inc. In 1994, Schneier published Applied Cryptography, which details the design and implementation of cryptographic algorithms. In 2010 he published Cryptography Engineering, focused more on how to use cryptography in real systems and less on its internal design, he has written books on security for a broader audience. In 2000, Schneier published Secrets and Lies: Digital Security in a Networked World. Schneier writes a available monthly Internet newsletter on computer and other security issues, Crypto-Gram, as well as a security weblog, Schneier on Security; the blog focuses on the latest threats, his own thoughts. The weblog started out as a way to publish essays before they appeared in Crypto-Gram, making it possible for others to comment on them while the stories were still current, but over time the newsletter became a monthly email version of the blog, re-edited and re-organized.
Schneier is quoted in the press on computer and other security issues, pointing out flaws in security and cryptographic implementations ranging from biometrics to airline security after the September 11 attacks. Schneier revealed on his blog that in the December 2004 issue of the SIGCSE Bulletin, three Pakistani academics, Khawaja Amer Hayat, Umar Waqar Anis, S. Tauseef-ur-Rehman, from the International Islamic University in Islamabad, plagiarized an article written by Schneier and got it published; the same academics subsequently plagiarized another article by Ville Hallivuori on "Real-time Transport Protocol security" as well. Schneier complained to the editors of the periodical; the editor of the SIGCSE Bulletin removed the paper from their website and demanded official letters of admission and apology. Schneier noted on his blog that International Islamic University personnel had requested him "to close comments in this blog entry". Schneier warns about misplaced trust in blockchain and the lack of use cases, calling Blockchain a solution in search of a problem.
"What blockchain does is shift some of the trust in people and institutions to trust in technology. You need to trust the protocols, the software, the computers and the network, and you need to trust them because they’re single points of failure." He goes on to say that cryptocurrencies are useless and are only used by speculators looking for quick riches. To Schneier, peer review and expert analysis are important for the security of cryptographic systems. Mathematical cryptography is not the weakest link in a security chain; the term Schneier's law was coined by Cory Doctorow in a 2004 speech. The law is phrased as: Any person can invent a security system so clever that he or she can't imagine a way of breaking it, he attributes this to Bruce Schneier, who wrote in 1998: "Anyone, from the most clueless amateur to the best cryptographer, can create an algorithm that he himself can't break. It's not hard. What is hard is creating an algorithm that no one else can break after years of analysis."Similar sentiments had been expressed by others before.
In The Codebreakers, David Kahn states: "Few false ideas have more gripped the minds of so many intelligent men than the one that, if they just tried, they could invent a cipher that no one could break", in "A Few Words On Secret Writing", in July 1841, Edgar Allan Poe had stated: "Few persons can be made to believe that it is not quite an easy thing to invent a method of secret writing which shall baffle investigation. Yet it may be roundly asserted that human ingenuity cannot concoct a cipher which human ingenuity cannot resolve." Schneier is critical of digital rights management and has said that it allows a vendor to increase lock-in. Proper implementation of control-based security for the user via trusted computing is difficult, security is not the same thing as control. Schneier is a proponent of full disclosure. If researchers don't go public, things don’t get fixed. Companies don't see it as a security problem. Schnei
International Cryptology Conference
CRYPTO, the International Cryptology Conference, is one of the largest academic conferences in cryptography and cryptanalysis. It is organized by the International Association for Cryptologic Research, it is held yearly in August in Santa Barbara, California at the University of California, Santa Barbara; the first CRYPTO was held in 1981. It was the first major conference on cryptology and was all the more important because relations between government and academia were rather tense. Encryption was considered a sensitive subject and the coming together of delegates from different countries was unheard-of at the time; the initiative for the formation of the IACR came during CRYPTO'82, CRYPTO'83 was the first IACR sponsored conference. ASIACRYPT EUROCRYPT List of cryptology conferences INDOCRYPT Bibliography of past CRYPTO conferences CRYPTO 2011
Telecommunications Industry Association
The Telecommunications Industry Association is accredited by the American National Standards Institute to develop voluntary, consensus-based industry standards for a wide variety of Information and Communication Technologies products, represents nearly 400 companies. TIA's Standards and Technology Department operates twelve engineering committees, which develop guidelines for private radio equipment, cellular towers, data terminals, telephone terminal equipment, accessibility, VoIP devices, structured cabling, data centers, mobile device communications, multimedia multicast, vehicular telematics, healthcare ICT, machine to machine communications, smart utility networks. Overall, more than 500 active participants, communications equipment manufacturers, service providers, government agencies, academic institutions, end-users are engaged in TIA's standards setting process. To ensure that these standards become incorporated globally, TIA is engaged in the International Telecommunication Union, the International Organization for Standardization, the International Electrotechnical Commission.
The Telecommunications Industry Assoc's most adopted standards include: TIA-942 Telecommunications Infrastructure Standard for Data Centers TIA-568-C. TIA-569-B Commercial Building Standards for Telecommunications Pathways and Spaces TIA-607-B TIA-598-C TIA-222-G Structural Standard for Antenna Supporting Structures and Antennas TIA-602-A Data Transmission Systems and Equipment, which standardized the common basic Hayes command set. TIA-102 - Land Mobile Communications for Public Safety TIA encourages engineers who represent the manufacturers and/or users of network equipment technology products and services, to become engaged in TIA's engineering committees, by voting and submitting technical contributions for inclusion in future standards. TIA is a participating standards organization of the ITU-T Global Standards Collaboration initiative; the GSC has created a Machine-to-Machine Standardization Task Force to foster industry collaboration on standards across different vertical markets, such as finance, e-health, connected vehicles, utilities.
TIA supported the E-LABEL Act, a bill that would direct the Federal Communications Commission to allow manufacturers of electronic devices with a screen to display information required by the agency digitally on the screen rather than on a label affixed to the device. Grant Seiffert argued that "by granting device manufacturers the ability to use e-labels, the legislation eases the technical and logistical burdens on manufactures and improves consumer access to important device information." Telecommunications Industry Association Website
David A. Wagner
David A. Wagner is a Professor of Computer Science at the University of California, Berkeley and a well-known researcher in cryptography and computer security, he is a member of the Election Assistance Commission's Technical Guidelines Development Committee, tasked with assisting the EAC in drafting the Voluntary Voting System Guidelines. He is a member of the ACCURATE project. Wagner received an A. B. in Mathematics from Princeton University in 1995, an M. S. in Computer Science from Berkeley in 1999, a Ph. D. in Computer Science from Berkeley in 2000. He has published two books and over 90 peer-reviewed scientific papers, his notable achievements include: 2007 Served as Principal Investigator for the source code review and the documentation review of the historic California state Top-to-Bottom review of electronic voting systems certified for use. Flaws found with vendor-supplied voting machines resulted in decertification and provisional recertification by the Secretary of State. 2001 Cryptanalysis of WEP, the security protocol used in 802.11 "WiFi" networks.
2000 Cryptanalysis of the A5/1 stream cipher used in GSM cellphones. 1999 Cryptanalysis of Microsoft's PPTP tunnelling protocol. 1999 Invention of the slide attack, a new form of cryptanalysis. 1998 Development of Twofish block cipher, a finalist for NIST's Advanced Encryption Standard competition. 1997 Cryptanalyzed the CMEA algorithm used in many U. S. cellphones. 1995 Discovered a flaw in the implementation of SSL in Netscape Navigator. Professor Wagner's home page David Wagner election research papers Some of Wagner's publications Interview and biography at the Wayback Machine Another interview