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A5/1

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A5/1 is a stream cipher used to provide over-the-air communication privacy in the GSM cellular telephone standard. It is one of several implementations of the A5 security protocol. It was initially kept secret, but became public knowledge through leaks and reverse engineering . A number of serious weaknesses in the cipher have been identified.

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108-520: A5/1 is used in Europe and 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, and A5/2 was developed in 1989. Though both were initially kept secret, the general design was leaked in 1994 and the algorithms were entirely reverse engineered in 1999 by Marc Briceno from

216-571: A customs union . A large bloc of countries, the Schengen Area , have also abolished internal border and immigration controls. Regular popular elections take place every five years within the EU; they are considered to be the second-largest democratic elections in the world after India's . The EU is the third-largest economy in the world. The place name Evros was first used by the ancient Greeks to refer to their northernmost province, which bears

324-456: 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 it should be, as they shared a long border with

432-871: A German naturalist, Peter Simon Pallas , as a valley that once connected the Black Sea and the Caspian Sea, and subsequently was proposed as a natural boundary between continents. By the mid-19th century, there were three main conventions, one following the Don, the Volga–Don Canal and the Volga, the other following the Kuma–Manych Depression to the Caspian and then the Ural River, and the third abandoning

540-643: A Semitic term for west , this being either Akkadian erebu meaning 'to go down, set' (said of the sun) or Phoenician 'ereb 'evening, west', which is at the origin of Arabic maghreb and Hebrew ma'arav . Martin Litchfield West stated that "phonologically, the match between Europa's name and any form of the Semitic word is very poor", while Beekes considers a connection to Semitic languages improbable. Most major world languages use words derived from Eurṓpē or Europa to refer to

648-818: A boundary along the Terek and Kuban rivers, so southwards from the Kuma and the Manych, but still with the Caucasus entirely in Asia. However, most geographers in the Soviet Union favoured the boundary along the Caucasus crest, and this became the common convention in the later 20th century, although the Kuma–Manych boundary remained in use in some 20th-century maps. Some view the separation of Eurasia into Asia and Europe as

756-488: A ciphertext-only attack on A5/2 that requires a few dozen milliseconds of encrypted off-the-air cellular conversation and finds the correct key in less than a second on a personal computer. We extend this attack to a (more complex) ciphertext-only attack on A5/1. We then describe new (active) attacks on the protocols of networks that use A5/1, A5/3, or even GPRS. These attacks exploit flaws in the GSM protocols, and they work whenever

864-407: A few seconds of known conversation". The attack was further improved by Elad Barkan and Eli Biham in 2005. In 2003, Barkan et al. published several attacks on GSM encryption. The first is an active attack. GSM phones can be convinced to use the much weaker A5/2 cipher briefly. A5/2 can be broken easily, and the phone uses the same key as for the stronger A5/1 algorithm. A second attack on A5/1

972-514: 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 also still be secure until the advent of quantum computing . Audestad, Peter van der Arend, and 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

1080-513: 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

1188-406: A large land mass completely or almost completely surrounded by water at its borders. Prior to the adoption of the current convention that includes mountain divides, the border between Europe and Asia had been redefined several times since its first conception in classical antiquity , but always as a series of rivers, seas and straits that were believed to extend an unknown distance east and north from

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1296-495: A practical attack on A5/1. The attack requires the construction of a large look-up table of approximately 3 terabytes. Together with the scanning capabilities developed as part of the sister project, the group expected to be able to record any GSM call or SMS encrypted with A5/1, and within about 3–5 minutes derive the encryption key and hence listen to the call and read the SMS in clear. But the tables weren't released. A similar effort,

1404-763: A precise eastern boundary of Europe arises in the Early Modern period, as the eastern extension of Muscovy began to include North Asia . Throughout the Middle Ages and into the 18th century, the traditional division of the landmass of Eurasia into two continents, Europe and Asia, followed Ptolemy, with the boundary following the Turkish Straits , the Black Sea , the Kerch Strait , the Sea of Azov and

1512-543: A range of national and regional cultures, which form the central roots of the wider Western civilisation , and together commonly reference ancient Greece and ancient Rome , particularly through their Christian successors , as crucial and shared roots. Beginning with the fall of the Western Roman Empire in 476 CE, Christian consolidation of Europe in the wake of the Migration Period marked

1620-711: A residue of Eurocentrism : "In physical, cultural and historical diversity, China and India are comparable to the entire European landmass, not to a single European country. [...]." During the 2.5 million years of the Pleistocene , numerous cold phases called glacials ( Quaternary ice age ), or significant advances of continental ice sheets, in Europe and North America, occurred at intervals of approximately 40,000 to 100,000 years. The long glacial periods were separated by more temperate and shorter interglacials which lasted about 10,000–15,000 years. The last cold episode of

1728-685: A result, the Reconquista took the greater part of eight hundred years, in which period a long list of Alfonsos, Sanchos, Ordoños, Ramiros, Fernandos, and Bermudos would be fighting their Christian rivals as much as the Muslim invaders. During the Dark Ages, the Western Roman Empire fell under the control of various tribes. The Germanic and Slav tribes established their domains over Western and Eastern Europe, respectively. Eventually

1836-485: A total work complexity of 2 A5/1 clockings given 2 bits of known plaintext . The attack requires 32 GB of data storage after a precomputation stage of 2. Ekdahl and Johansson published an attack on the initialisation procedure which breaks A5/1 in a few minutes using two to five minutes of conversation plaintext. This attack does not require a preprocessing stage. In 2004, Maximov et al. improved this result to an attack requiring "less than one minute of computations, and

1944-401: Is also evidence that Homo sapiens arrived in Europe around 54,000 years ago, some 10,000 years earlier than previously thought. The earliest sites in Europe dated 48,000 years ago are Riparo Mochi (Italy), Geissenklösterle (Germany) and Isturitz (France). The European Neolithic period—marked by the cultivation of crops and the raising of livestock, increased numbers of settlements and

2052-581: Is an Israeli cryptographer and cryptanalyst who is a professor at the Technion - Israel Institute of Technology Computer Science department. From 2008 to 2013, Biham was the dean of the Technion Computer Science department, after serving for two years as chief of CS graduate school. Biham invented (publicly) differential cryptanalysis , for which he received his Ph.D., while working under Adi Shamir . It had been invented before by

2160-415: Is clocked if the clocking bit agrees with the majority bit. Hence at each step at least two or three registers are clocked, and each register steps with probability 3/4. Initially, the registers are set to zero. Then for 64 cycles, the 64-bit secret key K is mixed in according to the following scheme: in cycle 0 ≤ i < 64 {\displaystyle 0\leq {i}<64} ,

2268-488: Is closest to Anatolia (or Asia Minor), but is considered part of Europe politically and it is a member state of the EU. Malta was considered an island of North-western Africa for centuries, but now it is considered to be part of Europe as well. "Europe", as used specifically in British English , may also refer to Continental Europe exclusively. The term "continent" usually implies the physical geography of

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2376-503: 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 2 (the units are in terms of number of solutions of a system of linear equations which are required). 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

2484-562: Is generally considered a transcontinental country divided entirely by water, while Russia and Kazakhstan are only partly divided by waterways. France, the Netherlands, Portugal and Spain are also transcontinental (or more properly, intercontinental, when oceans or large seas are involved) in that their main land areas are in Europe while pockets of their territories are located on other continents separated from Europe by large bodies of water. Spain, for example, has territories south of

2592-506: Is outlined, a ciphertext-only time-memory tradeoff attack which requires a large amount of precomputation. In 2006, Elad Barkan , Eli Biham , Nathan Keller published the full version of their 2003 paper, with attacks against A5/X сiphers. The authors claim: We present a very practical ciphertext-only cryptanalysis of GSM encrypted communication, and various active attacks on the GSM protocols. These attacks can even break into GSM networks that use "unbreakable" ciphers. We first describe

2700-478: Is sometimes considered to mark the end of antiquity; alternatively antiquity is considered to end with the fall of the Western Roman Empire in 476 CE; the closure of the pagan Platonic Academy of Athens in 529 CE; or the rise of Islam in the early 7th century CE. During most of its existence, the Byzantine Empire was one of the most powerful economic, cultural, and military forces in Europe. During

2808-422: Is somewhat arbitrary and inconsistent compared to any clear-cut definition of the term "continent". The current division of Eurasia into two continents now reflects East-West cultural, linguistic and ethnic differences which vary on a spectrum rather than with a sharp dividing line. The geographic border between Europe and Asia does not follow any state boundaries and now only follows a few bodies of water. Turkey

2916-399: Is then used in a stream cipher mode to maintain confidentiality. A5/1 is based around a combination of three linear-feedback shift registers (LFSRs) with irregular clocking. The three shift registers are specified as follows: These degrees were not chosen at random: since the degrees of the three registers are relatively prime, the period of this generator is the product of the periods of

3024-793: The Americas , almost all of Africa and Oceania , and the majority of Asia. The Age of Enlightenment , the French Revolution , and the Napoleonic Wars shaped the continent culturally, politically, and economically from the end of the 17th century until the first half of the 19th century. The Industrial Revolution , which began in Great Britain at the end of the 18th century, gave rise to radical economic, cultural, and social change in Western Europe and eventually

3132-845: The Carolingian Renaissance of the 9th century. From that time, the term designated the sphere of influence of the Western Church , as opposed to both the Eastern Orthodox churches and to the Islamic world . A cultural definition of Europe as the lands of Latin Christendom coalesced in the 8th century, signifying the new cultural condominium created through the confluence of Germanic traditions and Christian-Latin culture, defined partly in contrast with Byzantium and Islam , and limited to northern Iberia ,

3240-517: The Don (ancient Tanais ). But maps produced during the 16th to 18th centuries tended to differ in how to continue the boundary beyond the Don bend at Kalach-na-Donu (where it is closest to the Volga, now joined with it by the Volga–Don Canal ), into territory not described in any detail by the ancient geographers. Around 1715, Herman Moll produced a map showing the northern part of the Ob River and

3348-693: The East . This divide ended with the Revolutions of 1989 , the fall of the Berlin Wall , and the dissolution of the Soviet Union , which allowed European integration to advance significantly. European integration is being advanced institutionally since 1948 with the founding of the Council of Europe , and significantly through the realisation of the European Union (EU), which represents today

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3456-853: The Eastern Hemisphere . It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east. Europe shares the landmass of Eurasia with Asia, and of Afro-Eurasia with both Asia and Africa . Europe is commonly considered to be separated from Asia by the watershed of the Ural Mountains , the Ural River , the Caspian Sea ,

3564-628: The European population at the time. The plague had a devastating effect on Europe's social structure; it induced people to live for the moment as illustrated by Giovanni Boccaccio in The Decameron (1353). It was a serious blow to the Roman Catholic Church and led to increased persecution of Jews , beggars and lepers . The plague is thought to have returned every generation with varying virulence and mortalities until

3672-564: The Greater Caucasus , the Black Sea , and the waterway of the Bosporus Strait . Europe covers about 10.18 million km (3.93 million sq mi), or 2% of Earth's surface (6.8% of land area), making it the second-smallest continent (using the seven-continent model ). Politically, Europe is divided into about fifty sovereign states , of which Russia is the largest and most populous , spanning 39% of

3780-512: The Greeks and Phoenicians gave rise to early Mediterranean cities. Early Iron Age Italy and Greece from around the 8th century BCE gradually gave rise to historical Classical antiquity, whose beginning is sometimes dated to 776 BCE, the year of the first Olympic Games . Ancient Greece was the founding culture of Western civilisation. Western democratic and rationalist culture are often attributed to Ancient Greece. The Greek city-state,

3888-636: The Inquisition against heretics. In the Iberian Peninsula , the Reconquista concluded with the fall of Granada in 1492 , ending over seven centuries of Islamic rule in the south-western peninsula. In the east, a resurgent Byzantine Empire recaptured Crete and Cyprus from the Muslims, and reconquered the Balkans. Constantinople was the largest and wealthiest city in Europe from the 9th to

3996-733: The Irtysh River , a major tributary of the Ob, as components of a series of partly-joined waterways taking the boundary between Europe and Asia from the Turkish Straits, and the Don River all the way to the Arctic Ocean. In 1721, he produced a more up to date map that was easier to read. However, his proposal to adhere to major rivers as the line of demarcation was never taken up by other geographers who were beginning to move away from

4104-479: The Mediterranean Sea —namely, Ceuta and Melilla —which are parts of Africa and share a border with Morocco. According to the current convention, Georgia and Azerbaijan are transcontinental countries where waterways have been completely replaced by mountains as the divide between continents. The first recorded usage of Eurṓpē as a geographic term is in the Homeric Hymn to Delian Apollo , in reference to

4212-708: The Megalithic Temples of Malta and Stonehenge , were constructed throughout Western and Southern Europe. The modern native populations of Europe largely descend from three distinct lineages: Mesolithic hunter-gatherers , descended from populations associated with the Paleolithic Epigravettian culture; Neolithic Early European Farmers who migrated from Anatolia during the Neolithic Revolution 9,000 years ago; and Yamnaya Steppe herders who expanded into Europe from

4320-607: The Neandertal valley in Germany ) appeared in Europe 150,000 years ago (115,000 years ago it is found already in the territory of present-day Poland ) and disappeared from the fossil record about 40,000 years ago, with their final refuge being the Iberian Peninsula. The Neanderthals were supplanted by modern humans ( Cro-Magnons ), who seem to have appeared in Europe around 43,000 to 40,000 years ago. However, there

4428-655: The Pechenegs and the Cuman-Kipchaks , caused a massive migration of Slavic populations to the safer, heavily forested regions of the north, and temporarily halted the expansion of the Rus' state to the south and east. Like many other parts of Eurasia , these territories were overrun by the Mongols . The invaders, who became known as Tatars , were mostly Turkic-speaking peoples under Mongol suzerainty. They established

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4536-693: The Pontic–Caspian steppe of Ukraine and southern Russia in the context of Indo-European migrations 5,000 years ago. The European Bronze Age began c. 3200 BCE in Greece with the Minoan civilisation on Crete , the first advanced civilisation in Europe. The Minoans were followed by the Myceneans , who collapsed suddenly around 1200 BCE, ushering the European Iron Age . Iron Age colonisation by

4644-406: The Serbian Principality (later Kingdom and Empire ), and the Duchy of Croatia (later Kingdom of Croatia ). To the east, Kievan Rus' expanded from its capital in Kiev to become the largest state in Europe by the 10th century. In 988, Vladimir the Great adopted Orthodox Christianity as the religion of state. Further east, Volga Bulgaria became an Islamic state in the 10th century, but

4752-408: The Warsaw Pact ; but the other countries didn't feel this way, and the algorithm as now fielded is a French design." 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 which is XORed with

4860-419: 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 even GPRS that allow attackers to tap GSM mobile phone conversations and decrypt them either in real-time, or at any later time. According to professor Jan Arild Audestad, at the standardization process which started in 1982, A5/1 was originally proposed to have

4968-426: The decline of the Roman Empire , Europe entered a long period of change arising from what historians call the " Age of Migrations ". There were numerous invasions and migrations amongst the Ostrogoths , Visigoths , Goths , Vandals , Huns , Franks , Angles , Saxons , Slavs , Avars , Bulgars , Vikings , Pechenegs , Cumans , and Magyars . Renaissance thinkers such as Petrarch would later refer to this as

5076-507: The i th key bit is added to the least significant bit of each register using XOR — Each register is then clocked. Similarly, the 22-bits of the frame number are added in 22 cycles. Then 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, and

5184-432: The last glacial period ended about 10,000 years ago. Earth is currently in an interglacial period of the Quaternary, called the Holocene . Homo erectus georgicus , which lived roughly 1.8 million years ago in Georgia , is the earliest hominin to have been discovered in Europe. Other hominin remains, dating back roughly 1 million years, have been discovered in Atapuerca , Spain . Neanderthal man (named after

5292-517: The polis , was the fundamental political unit of classical Greece. In 508 BCE, Cleisthenes instituted the world's first democratic system of government in Athens . The Greek political ideals were rediscovered in the late 18th century by European philosophers and idealists. Greece also generated many cultural contributions: in philosophy , humanism and rationalism under Aristotle , Socrates and Plato ; in history with Herodotus and Thucydides ; in dramatic and narrative verse, starting with

5400-402: The "Dark Ages". Isolated monastic communities were the only places to safeguard and compile written knowledge accumulated previously; apart from this, very few written records survive. Much literature, philosophy, mathematics, and other thinking from the classical period disappeared from Western Europe, though they were preserved in the east, in the Byzantine Empire. While the Roman empire in

5508-497: 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 which yields proper 64 bits keys. When operating in GPRS / EDGE mode, higher bandwidth radio modulation allows for larger 348 bits frames, and A5/3

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5616-461: The 12th centuries, with a population of approximately 400,000. The Empire was weakened following the defeat at Manzikert , and was weakened considerably by the sack of Constantinople in 1204 , during the Fourth Crusade . Although it would recover Constantinople in 1261, Byzantium fell in 1453 when Constantinople was taken by the Ottoman Empire . In the 11th and 12th centuries, constant incursions by nomadic Turkic tribes, such as

5724-401: The 12th to the 15th centuries, the Grand Duchy of Moscow grew from a small principality under Mongol rule to the largest state in Europe, overthrowing the Mongols in 1480, and eventually becoming the Tsardom of Russia . The state was consolidated under Ivan III the Great and Ivan the Terrible , steadily expanding to the east and south over the next centuries. The Great Famine of 1315–1317

5832-490: The 14th and 16th centuries: it saw the flowering of art , philosophy , music , and the sciences , under the joint patronage of royalty , the nobility, the Roman Catholic Church and an emerging merchant class. Patrons in Italy, including the Medici family of Florentine bankers and the Popes in Rome , funded prolific quattrocento and cinquecento artists such as Raphael , Michelangelo and Leonardo da Vinci . Eli Biham Eli Biham ( Hebrew : אלי ביהם )

5940-444: The 18th century. During this period, more than 100 plague epidemics swept across Europe. The Renaissance was a period of cultural change originating in Florence , and later spreading to the rest of Europe. The rise of a new humanism was accompanied by the recovery of forgotten classical Greek and Arabic knowledge from monastic libraries, often translated from Arabic into Latin . The Renaissance spread across Europe between

6048-400: The 50 years of peace that followed are known as Golden Age of Athens , the seminal period of ancient Greece that laid many of the foundations of Western civilisation. Greece was followed by Rome , which left its mark on law , politics , language , engineering , architecture , government , and many more key aspects in western civilisation. By 200 BCE, Rome had conquered Italy and over

6156-405: The A5/1 Cracking Project attack tables for A5/1 were announced by Chris Paget and Karsten Nohl. The tables use a combination of compression techniques, including rainbow tables and distinguished point chains. These tables constituted only parts of the 1.7 TB completed table and had been computed during three months using 40 distributed CUDA nodes and then published over BitTorrent . More recently

6264-468: The A5/1 Cracking Project, was announced at the 2009 Black Hat security conference by cryptographers Karsten Nohl and Sascha Krißler. It created the look-up tables using Nvidia GPGPUs via a peer-to-peer distributed computing architecture. Starting in the middle of September 2009, the project ran the equivalent of 12 Nvidia GeForce GTX 260. According to the authors, the approach can be used on any cipher with key size up to 64-bits. In December 2009,

6372-403: The American National Security Agency is able to routinely 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. Originally, the weaknesses were passive attacks using the known plaintext assumption. In 2003, more serious weaknesses were identified which can be exploited in

6480-421: The British Isles, France, Christianised western Germany, the Alpine regions and northern and central Italy. The concept is one of the lasting legacies of the Carolingian Renaissance : Europa often figures in the letters of Charlemagne's court scholar, Alcuin . The transition of Europe to being a cultural term as well as a geographic one led to the borders of Europe being affected by cultural considerations in

6588-448: The Don altogether, following the Greater Caucasus watershed to the Caspian. The question was still treated as a "controversy" in geographical literature of the 1860s, with Douglas Freshfield advocating the Caucasus crest boundary as the "best possible", citing support from various "modern geographers". In Russia and the Soviet Union , the boundary along the Kuma–Manych Depression was the most commonly used as early as 1906. In 1958,

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6696-427: The Early Middle Ages, and soon spread throughout Europe. A struggle for influence between the nobility and the monarchy in England led to the writing of Magna Carta and the establishment of a parliament . The primary source of culture in this period came from the Roman Catholic Church . Through monasteries and cathedral schools , the Church was responsible for education in much of Europe. The Papacy reached

6804-452: The East, especially relating to areas under Byzantine, Ottoman, and Russian influence. Such questions were affected by the positive connotations associated with the term Europe by its users. Such cultural considerations were not applied to the Americas, despite their conquest and settlement by European states. Instead, the concept of "Western civilization" emerged as a way of grouping together Europe and these colonies. The question of defining

6912-427: The European post-classical Middle Ages . The Italian Renaissance spread in the continent a new humanist interest in art and science which led to the modern era . Since the Age of Discovery , led by Spain and Portugal , Europe played a predominant role in global affairs with multiple explorations and conquests around the world. Between the 16th and 20th centuries, European powers colonised at various times

7020-421: The Frankish tribes were united under Clovis I . Charlemagne , a Frankish king of the Carolingian dynasty who had conquered most of Western Europe, was anointed " Holy Roman Emperor " by the Pope in 800. This led in 962 to the founding of the Holy Roman Empire , which eventually became centred in the German principalities of central Europe. East Central Europe saw the creation of the first Slavic states and

7128-404: The Great 's efforts to make Russia more European, ignored the whole boundary question with his claim that neither Russia, Scandinavia, northern Germany, nor Poland were fully part of Europe. Since then, many modern analytical geographers like Halford Mackinder have declared that they see little validity in the Ural Mountains as a boundary between continents. The mapmakers continued to differ on

7236-427: The Levant and North Africa and making inroads into Asia Minor . In the mid-7th century, following the Muslim conquest of Persia , Islam penetrated into the Caucasus region. Over the next centuries Muslim forces took Cyprus , Malta , Crete , Sicily , and parts of southern Italy . Between 711 and 720, most of the lands of the Visigothic Kingdom of Iberia were brought under Muslim rule—save for small areas in

7344-414: The Mediterranean Sea without the inclusion of any mountain ranges. Cartographer Herman Moll suggested in 1715 Europe was bounded by a series of partly-joined waterways directed towards the Turkish straits, and the Irtysh River draining into the upper part of the Ob River and the Arctic Ocean . In contrast, the present eastern boundary of Europe partially adheres to the Ural and Caucasus Mountains, which

7452-433: The Soviet Geographical Society formally recommended that the boundary between the Europe and Asia be drawn in textbooks from Baydaratskaya Bay , on the Kara Sea , along the eastern foot of Ural Mountains, then following the Ural River until the Mugodzhar Hills , and then the Emba River ; and Kuma–Manych Depression, thus placing the Caucasus entirely in Asia and the Urals entirely in Europe. The Flora Europaea adopted

7560-400: The Tanais (the modern Don River) as the boundary. The Roman Empire did not attach a strong identity to the concept of continental divisions. However, following the fall of the Western Roman Empire , the culture that developed in its place , linked to Latin and the Catholic church, began to associate itself with the concept of "Europe". The term "Europe" is first used for a cultural sphere in

7668-422: The adoption of Christianity ( c. 1000 CE) . The powerful West Slavic state of Great Moravia spread its territory all the way south to the Balkans, reaching its largest territorial extent under Svatopluk I and causing a series of armed conflicts with East Francia . Further south, the first South Slavic states emerged in the late 7th and 8th century and adopted Christianity : the First Bulgarian Empire ,

7776-648: The basis of many modern legal systems, funded the construction of the Hagia Sophia and brought the Christian church under state control. From the 7th century onwards, as the Byzantines and neighbouring Sasanid Persians were severely weakened due to the protracted, centuries-lasting and frequent Byzantine–Sasanian wars , the Muslim Arabs began to make inroads into historically Roman territory, taking

7884-563: The boundary between the lower Don and Samara well into the 19th century. The 1745 atlas published by the Russian Academy of Sciences has the boundary follow the Don beyond Kalach as far as Serafimovich before cutting north towards Arkhangelsk , while other 18th- to 19th-century mapmakers such as John Cary followed Strahlenberg's prescription. To the south, the Kuma–Manych Depression was identified c.  1773 by

7992-400: The content of the conversation. Furthermore, we describe how to fortify the attacks to withstand reception errors. As a result, our attacks allow attackers to tap conversations and decrypt them either in real-time, or at any later time. In 2007 Universities of Bochum and Kiel started a research project to create a massively parallel FPGA -based cryptographic accelerator COPACOBANA. COPACOBANA

8100-468: The continent The prevalent definition of Europe as a geographical term has been in use since the mid-19th century. Europe is taken to be bounded by large bodies of water to the north, west and south; Europe's limits to the east and north-east are usually taken to be the Ural Mountains , the Ural River , and the Caspian Sea ; to the south-east, the Caucasus Mountains , the Black Sea , and

8208-573: The continent and comprising 15% of its population. Europe had a total population of about 745 million (about 10% of the world population ) in 2021; the third-largest after Asia and Africa. The European climate is affected by warm Atlantic currents, such as the Gulf Stream , which produce a temperate climate , tempering winters and summers, on much of the continent. Further from the sea, seasonal differences are more noticeable producing more continental climates . European culture consists of

8316-573: The continent. Chinese, for example, uses the word Ōuzhōu ( 歐洲 / 欧洲 ), which is an abbreviation of the transliterated name Ōuluóbā zhōu ( 歐羅巴洲 ) ( zhōu means "continent"); a similar Chinese-derived term Ōshū ( 欧州 ) is also sometimes used in Japanese such as in the Japanese name of the European Union, Ōshū Rengō ( 欧州連合 ) , despite the katakana Yōroppa ( ヨーロッパ ) being more commonly used. In some Turkic languages,

8424-640: The continents as the lands given by Noah to his three sons; Europe was defined as stretching from the Pillars of Hercules at the Strait of Gibraltar , separating it from Northwest Africa , to the Don, separating it from Asia. The convention received by the Middle Ages and surviving into modern usage is that of the Roman era used by Roman-era authors such as Posidonius , Strabo , and Ptolemy , who took

8532-640: The development of major commercial routes along the coast of the Mediterranean and Baltic Seas . The growing wealth and independence acquired by some coastal cities gave the Maritime Republics a leading role in the European scene. The Middle Ages on the mainland were dominated by the two upper echelons of the social structure: the nobility and the clergy. Feudalism developed in France in

8640-590: The epic poems of Homer ; in drama with Sophocles and Euripides ; in medicine with Hippocrates and Galen ; and in science with Pythagoras , Euclid , and Archimedes . In the course of the 5th century BCE, several of the Greek city states would ultimately check the Achaemenid Persian advance in Europe through the Greco-Persian Wars , considered a pivotal moment in world history, as

8748-584: The following two centuries it conquered Greece , Hispania ( Spain and Portugal ), the North African coast, much of the Middle East , Gaul ( France and Belgium ), and Britannia ( England and Wales ). Expanding from their base in central Italy beginning in the third century BCE, the Romans gradually expanded to eventually rule the entire Mediterranean basin and Western Europe by the turn of

8856-651: The height of its power during the High Middle Ages. An East-West Schism in 1054 split the former Roman Empire religiously, with the Eastern Orthodox Church in the Byzantine Empire and the Roman Catholic Church in the former Western Roman Empire. In 1095 Pope Urban II called for a crusade against Muslims occupying Jerusalem and the Holy Land . In Europe itself, the Church organised

8964-509: The idea of water boundaries as the only legitimate divides between Europe and Asia. Four years later, in 1725, Philip Johan von Strahlenberg was the first to depart from the classical Don boundary. He drew a new line along the Volga , following the Volga north until the Samara Bend , along Obshchy Syrt (the drainage divide between the Volga and Ural Rivers ), then north and east along

9072-429: 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 expensive preprocessing stage which requires 2 steps to compute around 300 GB of data. Several tradeoffs between preprocessing, data requirements, attack time and memory complexity are possible. The same year, Eli Biham and Orr Dunkelman also published an attack on A5/1 with

9180-596: The latter waterway to its source in the Ural Mountains . At this point he proposed that mountain ranges could be included as boundaries between continents as alternatives to nearby waterways. Accordingly, he drew the new boundary north along Ural Mountains rather than the nearby and parallel running Ob and Irtysh rivers. This was endorsed by the Russian Empire and introduced the convention that would eventually become commonly accepted. However, this did not come without criticism. Voltaire , writing in 1760 about Peter

9288-431: The majority of Europe. The European Union is a supranational political entity that lies between a confederation and a federation and is based on a system of European treaties . The EU originated in Western Europe but has been expanding eastward since the dissolution of the Soviet Union in 1991. A majority of its members have adopted a common currency, the euro , and participate in the European single market and

9396-577: The millennium. The Roman Republic ended in 27 BCE, when Augustus proclaimed the Roman Empire . The two centuries that followed are known as the pax romana , a period of unprecedented peace, prosperity and political stability in most of Europe. The empire continued to expand under emperors such as Antoninus Pius and Marcus Aurelius , who spent time on the Empire's northern border fighting Germanic , Pictish and Scottish tribes. Christianity

9504-453: The mobile phone supports a weak cipher such as A5/2. We emphasize that these attacks are on the protocols, and are thus applicable whenever the cellular phone supports a weak cipher, for example, they are also applicable for attacking A5/3 networks using the cryptanalysis of A5/1. Unlike previous attacks on GSM that require unrealistic information, like long known plaintext periods, our attacks are very practical and do not require any knowledge of

9612-710: The northwest ( Asturias ) and largely Basque regions in the Pyrenees . This territory, under the Arabic name Al-Andalus , became part of the expanding Umayyad Caliphate . The unsuccessful second siege of Constantinople (717) weakened the Umayyad dynasty and reduced their prestige. The Umayyads were then defeated by the Frankish leader Charles Martel at the Battle of Poitiers in 732, which ended their northward advance. In

9720-483: The originally Persian name Frangistan ("land of the Franks ") is used casually in referring to much of Europe, besides official names such as Avrupa or Evropa . Clickable map of Europe, showing one of the most commonly used continental boundaries Key: blue : states which straddle the border between Europe and Asia ; green : countries not geographically in Europe, but closely associated with

9828-507: The periods of the three LFSRs, which represents 2^64 bits (2 to the power of 64). One might think of using A5/1 as pseudo-random generator with a 64-bit initialization seed (key size), but it is not reliable. It loses its randomness after only 8 MB (which represents the period of the largest of the three registers). Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in

9936-501: The project has announced a switch to faster ATI Evergreen code, together with a change in the format of the tables and Frank A. Stevenson announced breaks of A5/1 using the ATI generated tables. Documents leaked by Edward Snowden in 2013 state that the NSA "can process encrypted A5/1". Since the degrees of the three LFSRs are relatively prime, the period of this generator is the product of

10044-497: The reconstructed Proto-Indo-European religion and the poetry devoted to it. An alternative view is that of Robert Beekes , who has argued in favour of a pre-Indo-European origin for the name, explaining that a derivation from eurus would yield a different toponym than Europa. Beekes has located toponyms related to that of Europa in the territory of ancient Greece, and localities such as that of Europos in ancient Macedonia . There have been attempts to connect Eurṓpē to

10152-507: The remote regions of north-western Iberia and the middle Pyrenees the power of the Muslims in the south was scarcely felt. It was here that the foundations of the Christian kingdoms of Asturias , Leon , and Galicia were laid and from where the reconquest of the Iberian Peninsula would start. However, no coordinated attempt would be made to drive the Moors out. The Christian kingdoms were mainly focused on their own internal power struggles. As

10260-692: The same name today. The principal river there – Evros (today's Maritsa ) – flows through the fertile valleys of Thrace , which itself was also called Europe, before the term meant the continent. In classical Greek mythology , Europa ( Ancient Greek : Εὐρώπη , Eurṓpē ) was a Phoenician princess. One view is that her name derives from the Ancient Greek elements εὐρύς ( eurús ) 'wide, broad', and ὤψ ( ōps , gen. ὠπός , ōpós ) 'eye, face, countenance', hence their composite Eurṓpē would mean 'wide-gazing' or 'broad of aspect'. Broad has been an epithet of Earth herself in

10368-535: The state of the Golden Horde with headquarters in Crimea, which later adopted Islam as a religion, and ruled over modern-day southern and central Russia for more than three centuries. After the collapse of Mongol dominions, the first Romanian states (principalities) emerged in the 14th century: Moldavia and Walachia . Previously, these territories were under the successive control of Pechenegs and Cumans. From

10476-401: The three registers. Thus the period of A5/1 (before repetition) is 2^64 bits (2 to the power of 64). The bits are indexed with the least significant bit (LSB) 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

10584-407: The waterways connecting the Black Sea to the Mediterranean Sea . Islands are generally grouped with the nearest continental landmass, hence Iceland is considered to be part of Europe, while the nearby island of Greenland is usually assigned to North America , although politically belonging to Denmark. Nevertheless, there are some exceptions based on sociopolitical and cultural differences. Cyprus

10692-562: The west and the north, transmitting newly acquired skills in producing copper artifacts. In Western Europe the Neolithic period was characterised not by large agricultural settlements but by field monuments, such as causewayed enclosures , burial mounds and megalithic tombs . The Corded Ware cultural horizon flourished at the transition from the Neolithic to the Chalcolithic . During this period giant megalithic monuments, such as

10800-535: The west continued to decline, Roman traditions and the Roman state remained strong in the predominantly Greek-speaking Eastern Roman Empire , also known as the Byzantine Empire . During most of its existence, the Byzantine Empire was the most powerful economic, cultural, and military force in Europe. Emperor Justinian I presided over Constantinople's first golden age: he established a legal code that forms

10908-518: The western shore of the Aegean Sea . As a name for a part of the known world, it is first used in the 6th century BCE by Anaximander and Hecataeus . Anaximander placed the boundary between Asia and Europe along the Phasis River (the modern Rioni River on the territory of Georgia ) in the Caucasus, a convention still followed by Herodotus in the 5th century BCE. Herodotus mentioned that

11016-772: The wider world. Both world wars began and were fought to a great extent in Europe, contributing to a decline in Western European dominance in world affairs by the mid-20th century as the Soviet Union and the United States took prominence and competed over dominance in Europe and globally. The resulting Cold War divided Europe along the Iron Curtain , with NATO in the West and the Warsaw Pact in

11124-739: The widespread use of pottery—began around 7000 BCE in Greece and the Balkans , probably influenced by earlier farming practices in Anatolia and the Near East . It spread from the Balkans along the valleys of the Danube and the Rhine ( Linear Pottery culture ), and along the Mediterranean coast ( Cardial culture ). Between 4500 and 3000 BCE, these central European neolithic cultures developed further to

11232-627: The world had been divided by unknown persons into three parts—Europe, Asia, and Libya (Africa)—with the Nile and the Phasis forming their boundaries—though he also states that some considered the River Don , rather than the Phasis, as the boundary between Europe and Asia. Europe's eastern frontier was defined in the 1st century by geographer Strabo at the River Don. The Book of Jubilees described

11340-422: Was legalised by Constantine I in 313 CE after three centuries of imperial persecution . Constantine also permanently moved the capital of the empire from Rome to the city of Byzantium (modern-day Istanbul ) which was renamed Constantinople in his honour in 330 CE. Christianity became the sole official religion of the empire in 380 CE, and in 391–392 CE the emperor Theodosius outlawed pagan religions. This

11448-619: Was eventually absorbed into Russia several centuries later. The period between the year 1000 and 1250 is known as the High Middle Ages , followed by the Late Middle Ages until c. 1500. During the High Middle Ages the population of Europe experienced significant growth, culminating in the Renaissance of the 12th century . Economic growth, together with the lack of safety on the mainland trading routes, made possible

11556-554: Was the first crisis that would strike Europe in the late Middle Ages. The period between 1348 and 1420 witnessed the heaviest loss. The population of France was reduced by half. Medieval Britain was afflicted by 95 famines, and France suffered the effects of 75 or more in the same period. Europe was devastated in the mid-14th century by the Black Death , one of the most deadly pandemics in human history which killed an estimated 25 million people in Europe alone—a third of

11664-490: Was the first commercially available solution using fast time-memory trade-off techniques that could be used to attack the popular A5/1 and A5/2 algorithms, used in GSM voice encryption, as well as the Data Encryption Standard (DES). It also enables brute force attacks against GSM eliminating the need of large precomputed lookup tables. In 2008, the group The Hackers Choice launched a project to develop

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