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Elbridge Gerry

Elbridge Gerry (July 17, 1744 – November 23, 1814) was an American Founding Father, merchant, politician, and diplomat who served as the fifth vice president of the United States under President James Madison from 1813 until his death in 1814. The political practice of gerrymandering is named after him.

Born into a wealthy merchant family, Gerry vocally opposed British colonial policy in the 1760s and was active in the early stages of organizing the resistance in the American Revolutionary War. Elected to the Second Continental Congress, Gerry signed both the Declaration of Independence and Articles of Confederation. He was one of three men who attended the Constitutional Convention in 1787, but refused to sign the Constitution because originally it did not include a Bill of Rights. After its ratification, he was elected to the inaugural United States Congress, where he was actively involved in the drafting and passage of the Bill of Rights as an advocate of individual and state liberties.

Gerry was at first opposed to the idea of political parties and cultivated enduring friendships on both sides of the political divide between Federalists and Democratic-Republicans. He was a member of a diplomatic delegation to France that was treated poorly in the XYZ Affair, in which Federalists held him responsible for a breakdown in negotiations. Gerry thereafter became a Democratic-Republican, running unsuccessfully for Governor of Massachusetts several times before winning the office in 1810. During his second term, the legislature approved new state senate districts that led to the coining of the word "gerrymander"; he lost the next election, although the state senate remained Democratic-Republican.

Gerry was nominated by the Democratic-Republican party and elected as vice president in the 1812 election. Advanced in age and in poor health, Gerry served 21 months of his term before dying in office. Gerry is the only signatory of the Declaration of Independence to be buried in Washington, D.C.

Early life and education
Gerry was born on July 17, 1744, in the North Shore town of Marblehead, Massachusetts. His father, Thomas Gerry (1702–1774), was a merchant who operated ships out of Marblehead, and his mother, Elizabeth (Greenleaf) Gerry (1716–1771), was the daughter of a successful Boston merchant. Gerry's first name came from John Elbridge, one of his mother's ancestors. Gerry's parents had 11 children in all, although only five survived to adulthood. Of these, Elbridge was the third. He was first educated by private tutors and entered Harvard College shortly before turning 14. After receiving a Bachelor of Arts degree in 1762 and a Master of Arts in 1765, he entered his father's merchant business. By the 1770s, the Gerrys numbered among the wealthiest Massachusetts merchants, with trading connections in Spain, the West Indies, and along the North American coast. Gerry's father, who had emigrated from England in 1730, was active in local politics and had a leading role in the local militia.

Colonial business and politics
Gerry was from an early time a vocal opponent of Parliamentary efforts to tax the colonies after the French and Indian War ended in 1763. In 1770, he sat on a Marblehead committee that sought to enforce importation bans on taxed British goods. He frequently communicated with other Massachusetts opponents of British policy, including Samuel Adams, John Adams, Mercy Otis Warren, and others.

In May 1772, he won election to the Great and General Court of the Province of Massachusetts Bay, which served as the state's legislative assembly. He worked closely with Samuel Adams to advance colonial opposition to Parliamentary colonial policies. He was responsible for establishing Marblehead's committee of correspondence, one of the first to be set up after that of Boston. However, an incident of mob action prompted him to resign from the committee the next year. Gerry and other prominent Marbleheaders had established a hospital for performing smallpox inoculations on Cat Island; because the means of transmission of the disease were not known at the time, fears amongst the local population led to protests which escalated into violence that wrecked the hospital and threatened the proprietors' other properties.

Gerry reentered politics after the Boston Port Act closed that city's port in 1774, and Marblehead became an alternative port to which relief supplies from other colonies could be delivered. As one of the town's leading merchants and Patriots, Gerry played a major role in ensuring the storage and delivery of supplies from Marblehead to Boston, interrupting those activities only to care for his dying father. He was elected as a representative to the First Continental Congress in September 1774, but declined, still grieving the loss of his father.

American Revolution

Gerry was elected to the provincial assembly, which reconstituted itself as the Massachusetts Provincial Congress after Governor Thomas Gage dissolved the body in October 1774. He was assigned to its committee of safety, responsible for ensuring that the province's limited supplies of weapons and gunpowder did not fall into British hands. His actions were partly responsible for the storage of weapons and ammunition in Concord; these stores were the target of the British expedition that sparked the start of the American Revolutionary War with the battles of Lexington and Concord in April 1775. (Gerry was staying at an inn at Menotomy, now Arlington, when the British Army marched through on the night of April 18.) During the Siege of Boston that followed, Gerry continued to take a leading role in supplying the nascent Continental Army, something he would continue to do as the war progressed. He leveraged business contacts in France and Spain to acquire not just munitions, but supplies of all types, and was involved in the transfer of financial subsidies from Spain to Congress. He sent ships to ports all along the American coast and dabbled in financing privateering operations against British merchant shipping.

Unlike some other merchants, there is no evidence that Gerry profiteered directly from the hostilities. He spoke out against price gouging and in favor of price controls, although his war-related merchant activities notably increased the family's wealth. His gains were tempered to some extent by the precipitous decline in the value of paper currencies, which he held in large quantities and speculated in.

Gerry served in the Second Continental Congress in Philadelphia from February 1776 to 1780, when matters of the ongoing war occupied the body's attention. He was influential in convincing several delegates to support passage of the Declaration of Independence in the debates held during the summer of 1776; John Adams wrote of him, "If every Man here was a Gerry, the Liberties of America would be safe against the Gates of Earth and Hell." He was implicated as a member of the so-called "Conway Cabal", a group of Congressmen and military officers who were dissatisfied with the performance of General George Washington during the 1777 military campaign. However, Gerry took Pennsylvania leader Thomas Mifflin, one of Washington's critics, to task early in the episode and specifically denied knowledge of any sort of conspiracy against Washington in February 1778.

Gerry's political philosophy was one of limited central government, and he regularly advocated for the maintenance of civilian control of the military. He held these positions fairly consistently throughout his political career (wavering principally on the need for stronger central government in the wake of the 1786–87 Shays' Rebellion) and was well known for his personal integrity. In later years he opposed the idea of political parties, remaining somewhat distant from both the developing Federalist and Democratic-Republican parties until later in his career. It was not until 1800 that he formally associated with the Democratic-Republicans in opposition to what he saw as attempts by the Federalists to centralize too much power in the national government.

In 1780, he resigned from the Continental Congress over the issue and refused offers from the state legislature to return to the Congress. He also refused appointment to the state senate, claiming he would be more effective in the state's lower chamber, and also refused appointment as a county judge, comparing the offer by Governor John Hancock to those made by royally-appointed governors to benefit their political allies. He was elected a fellow of the American Academy of Arts and Sciences in 1781.

Gerry was convinced to rejoin the Confederation Congress in 1783, when the state legislature agreed to support his call for needed reforms. He served in that body, which met in New York City, until September 1785. The following year, he married Ann Thompson, the daughter of a wealthy New York City merchant who was 20 years his junior; his best man was his good friend James Monroe. The couple had ten children between 1787 and 1801, straining Ann's health.

The war made Gerry sufficiently wealthy that when it ended he sold off his merchant interests and began investing in land. In 1787, he purchased the Cambridge, Massachusetts, estate of the last royal lieutenant governor of Massachusetts, Thomas Oliver, which had been confiscated by the state. This 100 acre property, known as Elmwood, became the family home for the rest of Gerry's life. He continued to own property in Marblehead and bought several properties in other Massachusetts communities. He also owned shares in the Ohio Company, prompting some political opponents to characterize him as an owner of vast tracts of western lands.

Constitutional Convention
Gerry played a major role in the Constitutional Convention held in Philadelphia during the summer of 1787. In its deliberations, he consistently advocated for a strong delineation between state and federal government powers, with state legislatures shaping the membership of federal government positions. Gerry's opposition to popular election of representatives was rooted in part by the events of Shays' Rebellion in western Massachusetts in the year preceding the convention. He also sought to maintain individual liberties by providing checks on government power that might abuse or limit those freedoms.

He supported the idea that the Senate composition should not be determined by population; the view that it should instead be composed of equal numbers of members for each state prevailed in the Connecticut Compromise. The compromise was adopted on a narrow vote in which the Massachusetts delegation was divided, Gerry and Caleb Strong voting in favor. Gerry further proposed that senators of a state, rather than casting a single vote on behalf of the state, vote instead as individuals. Gerry was also vocal in opposing the Three-fifths Compromise, which counted slaves as three-fifths of a free person for the purposes of apportionment in the House of Representatives, whereas counting each slave individually would have given southern slave states a decided advantage. Gerry opposed slavery and said the constitution should have "nothing to do" with slavery so as "not to sanction it."

Because of his fear of demagoguery and belief the people of the United States could be easily misled, Gerry also advocated indirect elections. Although he was unsuccessful in obtaining them for the lower house of Congress, Gerry did obtain such indirect elections for the Senate, whose members were to be selected by the state legislatures. Gerry also advanced numerous proposals for indirect elections of the President of the United States, most of them involving limiting the right to vote to the state governors and electors.

Gerry was unhappy about the lack of enumeration of any specific individual liberties in the proposed constitution and generally opposed proposals that strengthened the central government. He was one of only three delegates who voted against the proposed constitution in the convention (the others were George Mason and Edmund Randolph), citing a concern about the convention's lack of authority to enact such major changes to the nation's system of government and to the constitution's lack of "federal features." Ultimately, Gerry refused to sign because of concerns over the rights of private citizens and the power of the legislature to raise armies and revenue.

State ratification and Bill of Rights
During the ratification debates that took place in the states following the convention, Gerry continued his opposition, publishing a widely circulated letter documenting his objections to the proposed constitution. In the document, he cites the lack of a Bill of Rights as his primary objection but also expresses qualified approval of the Constitution, indicating that he would accept it with some amendment. Strong pro-Constitution forces attacked him in the press, comparing him unfavorably to the Shaysites. Henry Jackson was particularly vicious: "[Gerry has] done more injury to this country by that infamous Letter than he will be able to make atonement in his whole life", and Oliver Ellsworth, a convention delegate from Connecticut, charged him with deliberately courting the Shays faction.

One consequence of the furor over his letter was that he was not selected as a delegate to the Massachusetts ratifying convention although he was later invited to attend by the convention's leadership. The convention leadership was dominated by Federalists, and Gerry was not given any formal opportunity to speak. He left the convention after a shouting match with convention chair Francis Dana. Massachusetts ratified the constitution by a vote of 187 to 168. The debate had the result of estranging Gerry from several previously-friendly politicians, including chairman Dana and Rufus King.

U.S. House of Representatives

Anti-Federalist forces nominated Gerry for governor in 1788, but he was predictably defeated by the popular incumbent John Hancock. Following its ratification, Gerry recanted his opposition to the Constitution, noting that other state ratifying conventions had called for amendments that he supported. He was nominated by friends (over his own opposition to the idea) for a seat in the inaugural House of Representatives, where he served two terms.

In June 1789, Gerry proposed that Congress consider all of the proposed constitutional amendments that various state ratifying conventions had called for (notably those of Rhode Island and North Carolina, which had at the time still not ratified the Constitution). In the debate that followed, he led opposition to some of the proposals, arguing that they did not go far enough in ensuring individual liberties. He successfully lobbied for inclusion of freedom of assembly in the First Amendment and was a leading architect of the Fourth Amendment protections against search and seizure. He sought unsuccessfully to insert the word "expressly" into the Tenth Amendment, which might have more significantly limited the federal government's power.

He was successful in efforts to severely limit the federal government's ability to control state militias. In tandem with this protection, he had once argued against the idea of the federal government controlling a large standing army, saying, "A standing army is like a standing member. It's an excellent assurance of domestic tranquility, but a dangerous temptation to foreign adventure."

Gerry vigorously supported Alexander Hamilton's reports on public credit, including the assumption at full value of state debts, and supported Hamilton's Bank of the United States, positions consistent with earlier calls he had made for economic centralization. Although he had speculated in depreciated Continental bills of credit (the IOUs at issue), there is no evidence he participated in large-scale speculation that attended the debate when it took place in 1790, and he became a major investor in the new bank. He used the floor of the House to speak out against aristocratic and monarchical tendencies he saw as threats to republican ideals, and generally opposed laws and their provisions that he perceived as limiting individual and state liberties. He opposed any attempt to give officers of the executive significant powers, specifically opposing establishment of the Treasury Department because its head might gain more power than the president. He opposed measures that strengthened the presidency, such as the ability to fire Cabinet officers, seeking instead to give the legislature more power over appointments.

Gerry did not stand for re-election in 1792, returning home to raise his children and care for his sickly wife. He agreed to serve as a presidential elector for John Adams in the 1796 election. During Adams' term in office, Gerry maintained good relations with both Adams and Vice President Thomas Jefferson, hoping that the divided executive might lead to less friction. His hopes were not realized: the split between Federalists (Adams) and Democratic-Republicans (Jefferson) widened.

XYZ Affair

President Adams appointed Gerry to be a member of a special diplomatic commission sent to Republican France in 1797. Tensions had risen between the two nations after the 1796 ratification of the Jay Treaty, made between the United States and Great Britain. It was seen by French leaders as signs of an Anglo-American alliance, and France had consequently stepped up seizures of American ships. Adams chose Gerry over his cabinet's opposition (on political grounds that Gerry was insufficiently Federalist), because of their long-standing relationship; Adams described Gerry as one of the "two most impartial men in America" (Adams himself being the other).

Gerry joined co-commissioners Charles Cotesworth Pinckney and John Marshall in France in October 1797 and met briefly with Foreign Minister Talleyrand. Some days after that meeting, the delegation was approached by three French agents (at first identified as "X", "Y", and "Z" in published papers, leading the controversy to be called the "XYZ Affair") who demanded substantial bribes from the commissioners before negotiations could continue. The commissioners refused and sought unsuccessfully to engage Talleyrand in formal negotiations. Believing Gerry to be the most approachable of the commissioners, Talleyrand successively froze first Pinckney and then Marshall out of the informal negotiations, and they left France in April 1798. Gerry, who sought to leave with them, stayed behind because Talleyrand threatened war if he left. Gerry refused to make any significant negotiations afterward and left Paris in August.

By then, dispatches describing the commission's reception had been published in the United States, raising calls for war. The undeclared naval Quasi-War (1798–1800) followed. Federalists, notably Secretary of State Timothy Pickering, accused Gerry of supporting the French and abetting the breakdown of the talks, while Adams and Republicans such as Thomas Jefferson supported him. The negative press damaged Gerry's reputation, and he was burned in effigy by protestors in front of his home. He was only later vindicated, when his correspondence with Talleyrand was published in 1799. In response to the Federalist attacks on him, and because of his perception that the Federalist-led military buildup threatened republican values, Gerry formally joined the Democratic-Republican Party in early 1800, standing for election as Governor of Massachusetts.

Governor of Massachusetts

For years (in the 1800, 1801, 1802, and 1803 elections) Gerry unsuccessfully sought the governorship of Massachusetts. His opponent in these races, Caleb Strong, was a popular moderate Federalist, whose party dominated the state's politics despite a national shift toward the Republicans. In 1803, Republicans in the state were divided, and Gerry only had regional support of the party. He decided not to run in the 1804 election, returning to semi-retirement and to deal with a personal financial crisis. His brother Samuel Russell had mismanaged his own business affairs, and Gerry had propped him up by guaranteeing a loan that was due. The matter ultimately ruined Gerry's finances for his remaining years.

Republican James Sullivan won the governor's seat from Strong in the 1807 election, but his successor was unable to hold the seat in the 1809 election, which went to Federalist Christopher Gore. Gerry stood for election again in the 1810 election against Gore and won a narrow victory. Republicans cast Gore as an ostentatious British-loving Tory who wanted to restore the monarchy (his parents were Loyalists during the Revolution), and Gerry as a patriotic American, while Federalists described Gerry as a "French partizan" and Gore as an honest man devoted to ridding the government of foreign influence. A temporary lessening in the threat of war with Britain aided Gerry. The two battled again in 1811, with Gerry once again victorious in a highly acrimonious campaign.

Gerry's first year as governor was less controversial than his second, because the Federalists controlled the state senate. He preached moderation in the political discourse, noting that it was important that the nation present a unified front in its dealings with foreign powers. In his second term, with full Republican control of the legislature, he became notably more partisan, purging much of the state government of Federalist appointees. The legislature also enacted "reforms" of the court system that resulted in an increase in the number of judicial appointments, which Gerry filled with Republican partisans. However, infighting within the party and a shortage of qualified candidates played against Gerry, and the Federalists scored points by complaining vocally about the partisan nature of the reforms.

Other legislation passed during Gerry's second year included a bill broadening the membership of Harvard's Board of Overseers to diversify its religious membership, and another that liberalized religious taxes. The Harvard bill had significant political slant because the recent split between orthodox Congregationalists and Unitarians also divided the state to some extent along party lines, and Federalist Unitarians had recently gained control over the Harvard board.

In 1812, the state adopted new constitutionally mandated electoral district boundaries. The Republican-controlled legislature had created district boundaries designed to enhance their party's control over state and national offices, leading to some oddly shaped legislative districts. Although Gerry was unhappy about the highly partisan districting (according to his son-in-law, he thought it "highly disagreeable"), he signed the legislation. The shape of one of the state senate districts in Essex County was compared to a salamander by a local Federalist newspaper in a political cartoon, calling it a "Gerry-mander". Ever since, the creation of such districts has been called gerrymandering.

Gerry also engaged in partisan investigations of potential libel against him by elements of the Federalist press, further damaging his popularity with moderates. The redistricting controversy, along with the libel investigation and the impending War of 1812, contributed to Gerry's defeat in 1812 (once again at the hands of Caleb Strong, whom the Federalists had brought out of retirement). The gerrymandering of the state Senate was a notable success in the 1812 election: the body was thoroughly dominated by Republicans, even though the house and the governor's seat went to Federalists by substantial margins.

Vice presidency and death
Gerry's financial difficulties prompted him to ask President James Madison for a federal position after his loss in the 1812 election (which was held early in the year). He was chosen by the party Congressional nominating caucus to be Madison's vice presidential running mate in the 1812 presidential election, although the nomination was first offered to John Langdon. He was viewed as a relatively safe choice who would attract Northern votes but not pose a threat to James Monroe, who was thought likely to succeed Madison. Madison narrowly won re-election, and Gerry took the oath of office at Elmwood in March 1813. At that time the office of vice president was largely a sinecure; Gerry's duties included advancing the administration's agenda in Congress and dispensing patronage positions in New England. Gerry's actions in support of the War of 1812 had a partisan edge: he expressed concerns over a possible Federalist seizure of Fort Adams (as Boston's Fort Independence was then known) as a prelude to Anglo-Federalist cooperation and sought the arrest of printers of Federalist newspapers.

On November 23, 1814, Gerry suffered a heart attack while visiting Joseph Nourse of the Treasury Department, and he died soon after returning to his home in the Seven Buildings. He was 70 years old.

He is buried in the Congressional Cemetery in Washington, D.C., with a memorial by John Frazee. He is the only signer of the Declaration of Independence who was buried in the nation's capital city. The estate he left his wife and children was rich in land and poor in cash, but he had managed to repay his brother's debts with his pay as vice president. Aged 68 at the start of his vice presidency, he was the oldest person to become vice president until Charles Curtis in 1929.

Legacy
Gerry is generally remembered for the use of his name in the word gerrymander, for his refusal to sign the United States Constitution, and for his role in the XYZ Affair. His path through the politics of the age has been difficult to characterize. Early biographers, including his son-in-law James T. Austin and Samuel Eliot Morison, struggled to explain his apparent changes in position. Biographer George Athan Billias posits that Gerry was a consistent advocate and practitioner of republicanism as it was originally envisioned, and that his role in the Constitutional Convention had a significant impact on the document it eventually produced.

Gerry had ten children, nine of whom survived into adulthood:

 * 1) Catharine Gerry (1787–1850)
 * 2) Eliza Gerry (1791–1882)
 * 3) Ann Gerry (1791–1883)
 * 4) Elbridge Gerry, Jr. (1793–1867)
 * 5) Thomas Russell Gerry (1794–1848), who married Hannah Green Goelet (1804–1845)
 * 6) Helen Maria Gerry (1796–1864)
 * 7) James Thompson Gerry (1797–1854), who left West Point upon his father's death and was commander of the war-sloop USS Albany; the sloop disappeared with all hands September 28 or 29, 1854 near the West Indies.
 * 8) Eleanor Stanford Gerry (1800–1871)
 * 9) Emily Louisa Gerry (1802–1894)

Gerry's grandson Elbridge Thomas Gerry became a distinguished lawyer and philanthropist in New York. His great-grandson, Peter G. Gerry, was a member of the U.S. House of Representatives and later a U.S. Senator from Rhode Island.

Gerry is depicted in two of John Trumbull's paintings, the Declaration of Independence and General George Washington Resigning His Commission. Both are on view in the rotunda of the United States Capitol.

The upstate New York town of Elbridge is believed to have been named in his honor, as is the western New York town of Gerry. The town of Phillipston, Massachusetts was originally incorporated in 1786 under the name Gerry in his honor but was changed to its present name after the town submitted a petition in 1812, citing Democratic-Republican support for the War of 1812.

Gerry's Landing Road in Cambridge, Massachusetts, is located near the Eliot Bridge not far from Elmwood. During the 19th century, the area was known as Gerry's Landing (formerly known as Sir Richard's Landing) and was used by a Gerry relative for a short time as a landing and storehouse. The supposed house of his birth, the Elbridge Gerry House (it is uncertain whether he was born in the house currently standing on the site or an earlier structure) stands in Marblehead, and Marblehead's Elbridge Gerry School is named in his honor.

title: Elbridge Gerry


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Encryption

In cryptography, encryption is the process of transforming (more specifically, encoding) information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Despite its goal, encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor.

For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users.

Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in military messaging. Since then, new techniques have emerged and become commonplace in all areas of modern computing. Modern encryption schemes use the concepts of public-key and symmetric-key. Modern encryption techniques ensure security because modern computers are inefficient at cracking the encryption.

Ancient
One of the earliest forms of encryption is symbol replacement, which was first found in the tomb of Khnumhotep II, who lived in 1900 BC Egypt. Symbol replacement encryption is “non-standard,” which means that the symbols require a cipher or key to understand. This type of early encryption was used throughout Ancient Greece and Rome for military purposes. One of the most famous military encryption developments was the Caesar Cipher, which was a system in which a letter in normal text is shifted down a fixed number of positions down the alphabet to get the encoded letter. A message encoded with this type of encryption could be decoded with the fixed number on the Caesar Cipher.

Around 800 AD, Arab mathematician Al-Kindi developed the technique of frequency analysis – which was an attempt to systematically crack Caesar ciphers. This technique looked at the frequency of letters in the encrypted message to determine the appropriate shift. This technique was rendered ineffective after the creation of the polyalphabetic cipher by Leon Battista Alberti in 1465, which incorporated different sets of languages. In order for frequency analysis to be useful, the person trying to decrypt the message would need to know which language the sender chose.

19th–20th century
Around 1790, Thomas Jefferson theorized a cipher to encode and decode messages in order to provide a more secure way of military correspondence. The cipher, known today as the Wheel Cipher or the Jefferson Disk, although never actually built, was theorized as a spool that could jumble an English message up to 36 characters. The message could be decrypted by plugging in the jumbled message to a receiver with an identical cipher.

A similar device to the Jefferson Disk, the M-94, was developed in 1917 independently by US Army Major Joseph Mauborne. This device was used in U.S. military communications until 1942.

In World War II, the Axis powers used a more advanced version of the M-94 called the Enigma Machine. The Enigma Machine was more complex because unlike the Jefferson Wheel and the M-94, each day the jumble of letters switched to a completely new combination. Each day's combination was only known by the Axis, so many thought the only way to break the code would be to try over 17,000 combinations within 24 hours. The Allies used computing power to severely limit the number of reasonable combinations they needed to check every day, leading to the breaking of the Enigma Machine.

Modern
Today, encryption is used in the transfer of communication over the Internet for security and commerce. As computing power continues to increase, computer encryption is constantly evolving to prevent eavesdropping attacks. With one of the first "modern" cipher suites, DES, utilizing a 56-bit key with 72,057,594,037,927,936 possibilities being able to be cracked in 22 hours and 15 minutes by EFF's DES cracker in 1999, which used a brute-force method of cracking. Modern encryption standards often use stronger key sizes often 256, like AES (256-bit mode), TwoFish, ChaCha20-Poly1305, Serpent (configurable up to 512-bit). Cipher suites utilizing a 128-bit or higher key, like AES, will not be able to be brute-forced due to the total amount of keys of 3.4028237e+38 possibilities. The most likely option for cracking ciphers with high key size is to find vulnerabilities in the cipher itself, like inherent biases and backdoors or by exploiting physical side effects through Side-channel attacks. For example, RC4, a stream cipher, was cracked due to inherent biases and vulnerabilities in the cipher.

Encryption in cryptography
In the context of cryptography, encryption serves as a mechanism to ensure confidentiality. Since data may be visible on the Internet, sensitive information such as passwords and personal communication may be exposed to potential interceptors. The process of encrypting and decrypting messages involves keys. The two main types of keys in cryptographic systems are symmetric-key and public-key (also known as asymmetric-key).

Many complex cryptographic algorithms often use simple modular arithmetic in their implementations.

Types
In symmetric-key schemes, the encryption and decryption keys are the same. Communicating parties must have the same key in order to achieve secure communication. The German Enigma Machine utilized a new symmetric-key each day for encoding and decoding messages.

In public-key encryption schemes, the encryption key is published for anyone to use and encrypt messages. However, only the receiving party has access to the decryption key that enables messages to be read. Public-key encryption was first described in a secret document in 1973; beforehand, all encryption schemes were symmetric-key (also called private-key). Although published subsequently, the work of Diffie and Hellman was published in a journal with a large readership, and the value of the methodology was explicitly described. The method became known as the Diffie-Hellman key exchange.

RSA (Rivest–Shamir–Adleman) is another notable public-key cryptosystem. Created in 1978, it is still used today for applications involving digital signatures. Using number theory, the RSA algorithm selects two prime numbers, which help generate both the encryption and decryption keys.

A publicly available public-key encryption application called Pretty Good Privacy (PGP) was written in 1991 by Phil Zimmermann, and distributed free of charge with source code. PGP was purchased by Symantec in 2010 and is regularly updated.

Uses
Encryption has long been used by militaries and governments to facilitate secret communication. It is now commonly used in protecting information within many kinds of civilian systems. For example, the Computer Security Institute reported that in 2007, 71% of companies surveyed utilized encryption for some of their data in transit, and 53% utilized encryption for some of their data in storage. Encryption can be used to protect data "at rest", such as information stored on computers and storage devices (e.g. USB flash drives). In recent years, there have been numerous reports of confidential data, such as customers' personal records, being exposed through loss or theft of laptops or backup drives; encrypting such files at rest helps protect them if physical security measures fail. Digital rights management systems, which prevent unauthorized use or reproduction of copyrighted material and protect software against reverse engineering (see also copy protection), is another somewhat different example of using encryption on data at rest.

Encryption is also used to protect data in transit, for example data being transferred via networks (e.g. the Internet, e-commerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines. There have been numerous reports of data in transit being intercepted in recent years. Data should also be encrypted when transmitted across networks in order to protect against eavesdropping of network traffic by unauthorized users.

Data erasure
Conventional methods for permanently deleting data from a storage device involve overwriting the device's whole content with zeros, ones, or other patterns – a process which can take a significant amount of time, depending on the capacity and the type of storage medium. Cryptography offers a way of making the erasure almost instantaneous. This method is called crypto-shredding. An example implementation of this method can be found on iOS devices, where the cryptographic key is kept in a dedicated 'effaceable storage'. Because the key is stored on the same device, this setup on its own does not offer full privacy or security protection if an unauthorized person gains physical access to the device.

Limitations
Encryption is used in the 21st century to protect digital data and information systems. As computing power increased over the years, encryption technology has only become more advanced and secure. However, this advancement in technology has also exposed a potential limitation of today's encryption methods.

The length of the encryption key is an indicator of the strength of the encryption method. For example, the original encryption key, DES (Data Encryption Standard), was 56 bits, meaning it had 2^56 combination possibilities. With today's computing power, a 56-bit key is no longer secure, being vulnerable to brute force attacks.

Quantum computing utilizes properties of quantum mechanics in order to process large amounts of data simultaneously. Quantum computing has been found to achieve computing speeds thousands of times faster than today's supercomputers. This computing power presents a challenge to today's encryption technology. For example, RSA encryption utilizes the multiplication of very large prime numbers to create a semiprime number for its public key. Decoding this key without its private key requires this semiprime number to be factored, which can take a very long time to do with modern computers. It would take a supercomputer anywhere between weeks to months to factor in this key. However, quantum computing can use quantum algorithms to factor this semiprime number in the same amount of time it takes for normal computers to generate it. This would make all data protected by current public-key encryption vulnerable to quantum computing attacks. Other encryption techniques like elliptic curve cryptography and symmetric key encryption are also vulnerable to quantum computing.

While quantum computing could be a threat to encryption security in the future, quantum computing as it currently stands is still very limited. Quantum computing currently is not commercially available, cannot handle large amounts of code, and only exists as computational devices, not computers. Furthermore, quantum computing advancements will be able to be utilized in favor of encryption as well. The National Security Agency (NSA) is currently preparing post-quantum encryption standards for the future. Quantum encryption promises a level of security that will be able to counter the threat of quantum computing.

Attacks and countermeasures
Encryption is an important tool but is not sufficient alone to ensure the security or privacy of sensitive information throughout its lifetime. Most applications of encryption protect information only at rest or in transit, leaving sensitive data in clear text and potentially vulnerable to improper disclosure during processing, such as by a cloud service for example. Homomorphic encryption and secure multi-party computation are emerging techniques to compute encrypted data; these techniques are general and Turing complete but incur high computational and/or communication costs.

In response to encryption of data at rest, cyber-adversaries have developed new types of attacks. These more recent threats to encryption of data at rest include cryptographic attacks, stolen ciphertext attacks, attacks on encryption keys, insider attacks, data corruption or integrity attacks, data destruction attacks, and ransomware attacks. Data fragmentation and active defense data protection technologies attempt to counter some of these attacks, by distributing, moving, or mutating ciphertext so it is more difficult to identify, steal, corrupt, or destroy.

The debate around encryption
The question of balancing the need for national security with the right to privacy has been debated for years, since encryption has become critical in today's digital society. The modern encryption debate started around the '90s when US government tried to ban cryptography because, according to them, it would threaten national security. The debate is polarized around two opposing views. Those who see strong encryption as a problem making it easier for criminals to hide their illegal acts online and others who argue that encryption keep digital communications safe. The debate heated up in 2014, when Big Tech like Apple and Google set encryption by default in their devices. This was the start of a series of controversies that puts governments, companies and internet users at stake.

Integrity protection of Ciphertexts
Encryption, by itself, can protect the confidentiality of messages, but other techniques are still needed to protect the integrity and authenticity of a message; for example, verification of a message authentication code (MAC) or a digital signature usually done by a hashing algorithm or a PGP signature. Authenticated encryption algorithms are designed to provide both encryption and integrity protection together. Standards for cryptographic software and hardware to perform encryption are widely available, but successfully using encryption to ensure security may be a challenging problem. A single error in system design or execution can allow successful attacks. Sometimes an adversary can obtain unencrypted information without directly undoing the encryption. See for example traffic analysis, TEMPEST, or Trojan horse.

Integrity protection mechanisms such as MACs and digital signatures must be applied to the ciphertext when it is first created, typically on the same device used to compose the message, to protect a message end-to-end along its full transmission path; otherwise, any node between the sender and the encryption agent could potentially tamper with it. Encrypting at the time of creation is only secure if the encryption device itself has correct keys and has not been tampered with. If an endpoint device has been configured to trust a root certificate that an attacker controls, for example, then the attacker can both inspect and tamper with encrypted data by performing a man-in-the-middle attack anywhere along the message's path. The common practice of TLS interception by network operators represents a controlled and institutionally sanctioned form of such an attack, but countries have also attempted to employ such attacks as a form of control and censorship.

Ciphertext length and padding
Even when encryption correctly hides a message's content and it cannot be tampered with at rest or in transit, a message's length is a form of metadata that can still leak sensitive information about the message. For example, the well-known CRIME and BREACH attacks against HTTPS were side-channel attacks that relied on information leakage via the length of encrypted content. Traffic analysis is a broad class of techniques that often employs message lengths to infer sensitive implementation about traffic flows by aggregating information about a large number of messages.

Padding a message's payload before encrypting it can help obscure the cleartext's true length, at the cost of increasing the ciphertext's size and introducing or increasing bandwidth overhead. Messages may be padded randomly or deterministically, with each approach having different tradeoffs. Encrypting and padding messages to form padded uniform random blobs or PURBs is a practice guaranteeing that the cipher text leaks no metadata about its cleartext's content, and leaks asymptotically minimal $$O(\log\log M)$$ information via its length.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Encryption


text:
Einstein–Podolsky–Rosen paradox

The Einstein–Podolsky–Rosen (EPR) paradox is a thought experiment proposed by physicists Albert Einstein, Boris Podolsky and Nathan Rosen which argues that the description of physical reality provided by quantum mechanics is incomplete. In a 1935 paper titled "Can Quantum-Mechanical Description of Physical Reality be Considered Complete?", they argued for the existence of "elements of reality" that were not part of quantum theory, and speculated that it should be possible to construct a theory containing these hidden variables. Resolutions of the paradox have important implications for the interpretation of quantum mechanics.

The thought experiment involves a pair of particles prepared in what would later become known as an entangled state. Einstein, Podolsky, and Rosen pointed out that, in this state, if the position of the first particle were measured, the result of measuring the position of the second particle could be predicted. If instead the momentum of the first particle were measured, then the result of measuring the momentum of the second particle could be predicted. They argued that no action taken on the first particle could instantaneously affect the other, since this would involve information being transmitted faster than light, which is impossible according to the theory of relativity. They invoked a principle, later known as the "EPR criterion of reality", positing that: "If, without in any way disturbing a system, we can predict with certainty (i.e., with probability equal to unity) the value of a physical quantity, then there exists an element of reality corresponding to that quantity." From this, they inferred that the second particle must have a definite value of both position and of momentum prior to either quantity being measured. But quantum mechanics considers these two observables incompatible and thus does not associate simultaneous values for both to any system. Einstein, Podolsky, and Rosen therefore concluded that quantum theory does not provide a complete description of reality.

The "Paradox" paper
The term "Einstein–Podolsky–Rosen paradox" or "EPR" arose from a paper written in 1934 after Einstein joined the Institute for Advanced Study, having fled the rise of Nazi Germany. The original paper purports to describe what must happen to "two systems I and II, which we permit to interact", and after some time "we suppose that there is no longer any interaction between the two parts." The EPR description involves "two particles, A and B, [which] interact briefly and then move off in opposite directions." According to Heisenberg's uncertainty principle, it is impossible to measure both the momentum and the position of particle B exactly; however, it is possible to measure the exact position of particle A. By calculation, therefore, with the exact position of particle A known, the exact position of particle B can be known. Alternatively, the exact momentum of particle A can be measured, so the exact momentum of particle B can be worked out. As Manjit Kumar writes, "EPR argued that they had proved that ... [particle] B can have simultaneously exact values of position and momentum. ... Particle B has a position that is real and a momentum that is real. EPR appeared to have contrived a means to establish the exact values of either the momentum or the position of B due to measurements made on particle A, without the slightest possibility of particle B being physically disturbed."

EPR tried to set up a paradox to question the range of true application of quantum mechanics: Quantum theory predicts that both values cannot be known for a particle, and yet the EPR thought experiment purports to show that they must all have determinate values. The EPR paper says: "We are thus forced to conclude that the quantum-mechanical description of physical reality given by wave functions is not complete." The EPR paper ends by saying: "While we have thus shown that the wave function does not provide a complete description of the physical reality, we left open the question of whether or not such a description exists. We believe, however, that such a theory is possible." The 1935 EPR paper condensed the philosophical discussion into a physical argument. The authors claim that given a specific experiment, in which the outcome of a measurement is known before the measurement takes place, there must exist something in the real world, an "element of reality", that determines the measurement outcome. They postulate that these elements of reality are, in modern terminology, local, in the sense that each belongs to a certain point in spacetime. Each element may, again in modern terminology, only be influenced by events which are located in the backward light cone of its point in spacetime (i.e. in the past). These claims are founded on assumptions about nature that constitute what is now known as local realism.

Though the EPR paper has often been taken as an exact expression of Einstein's views, it was primarily authored by Podolsky, based on discussions at the Institute for Advanced Study with Einstein and Rosen. Einstein later expressed to Erwin Schrödinger that, "it did not come out as well as I had originally wanted; rather, the essential thing was, so to speak, smothered by the formalism." Einstein would later go on to present an individual account of his local realist ideas. Shortly before the EPR paper appeared in the Physical Review, The New York Times ran a news story about it, under the headline "Einstein Attacks Quantum Theory". The story, which quoted Podolsky, irritated Einstein, who wrote to the Times, "Any information upon which the article 'Einstein Attacks Quantum Theory' in your issue of May 4 is based was given to you without authority. It is my invariable practice to discuss scientific matters only in the appropriate forum and I deprecate advance publication of any announcement in regard to such matters in the secular press."

The Times story also sought out comment from physicist Edward Condon, who said, "Of course, a great deal of the argument hinges on just what meaning is to be attached to the word 'reality' in physics." The physicist and historian Max Jammer later noted, "[I]t remains a historical fact that the earliest criticism of the EPR paper — moreover, a criticism which correctly saw in Einstein's conception of physical reality the key problem of the whole issue — appeared in a daily newspaper prior to the publication of the criticized paper itself."

Bohr's reply
The publication of the paper prompted a response by Niels Bohr, which he published in the same journal (Physical Review), in the same year, using the same title. (This exchange was only one chapter in a prolonged debate between Bohr and Einstein about the nature of quantum reality.) He argued that EPR had reasoned fallaciously. Bohr said measurements of position and of momentum are complementary, meaning the choice to measure one excludes the possibility of measuring the other. Consequently, a fact deduced regarding one arrangement of laboratory apparatus could not be combined with a fact deduced by means of the other, and so, the inference of predetermined position and momentum values for the second particle was not valid. Bohr concluded that EPR's "arguments do not justify their conclusion that the quantum description turns out to be essentially incomplete."

Einstein's own argument
In his own publications and correspondence, Einstein indicated that he was not satisfied with the EPR paper and that Rosen had authored most of it. He later used a different argument to insist that quantum mechanics is an incomplete theory. He explicitly de-emphasized EPR's attribution of "elements of reality" to the position and momentum of particle B, saying that "I couldn't care less" whether the resulting states of particle B allowed one to predict the position and momentum with certainty.

For Einstein, the crucial part of the argument was the demonstration of nonlocality, that the choice of measurement done in particle A, either position or momentum, would lead to two different quantum states of particle B. He argued that, because of locality, the real state of particle B could not depend on which kind of measurement was done in A and that the quantum states therefore cannot be in one-to-one correspondence with the real states. Einstein struggled unsuccessfully for the rest of his life to find a theory that could better comply with his idea of locality.

Bohm's variant
In 1951, David Bohm proposed a variant of the EPR thought experiment in which the measurements have discrete ranges of possible outcomes, unlike the position and momentum measurements considered by EPR. The EPR–Bohm thought experiment can be explained using electron–positron pairs. Suppose we have a source that emits electron–positron pairs, with the electron sent to destination A, where there is an observer named Alice, and the positron sent to destination B, where there is an observer named Bob. According to quantum mechanics, we can arrange our source so that each emitted pair occupies a quantum state called a spin singlet. The particles are thus said to be entangled. This can be viewed as a quantum superposition of two states, which we call state I and state II. In state I, the electron has spin pointing upward along the z-axis (+z) and the positron has spin pointing downward along the z-axis (−z). In state II, the electron has spin −z and the positron has spin +z. Because it is in a superposition of states, it is impossible without measuring to know the definite state of spin of either particle in the spin singlet.

Alice now measures the spin along the z-axis. She can obtain one of two possible outcomes: +z or −z. Suppose she gets +z. Informally speaking, the quantum state of the system collapses into state I. The quantum state determines the probable outcomes of any measurement performed on the system. In this case, if Bob subsequently measures spin along the z-axis, there is 100% probability that he will obtain −z. Similarly, if Alice gets −z, Bob will get +z. There is nothing special about choosing the z-axis: according to quantum mechanics the spin singlet state may equally well be expressed as a superposition of spin states pointing in the x direction.

Whatever axis their spins are measured along, they are always found to be opposite. In quantum mechanics, the x-spin and z-spin are "incompatible observables", meaning the Heisenberg uncertainty principle applies to alternating measurements of them: a quantum state cannot possess a definite value for both of these variables. Suppose Alice measures the z-spin and obtains +z, so that the quantum state collapses into state I. Now, instead of measuring the z-spin as well, Bob measures the x-spin. According to quantum mechanics, when the system is in state I, Bob's x-spin measurement will have a 50% probability of producing +x and a 50% probability of -x. It is impossible to predict which outcome will appear until Bob actually performs the measurement. Therefore, Bob's positron will have a definite spin when measured along the same axis as Alice's electron, but when measured in the perpendicular axis its spin will be uniformly random. It seems as if information has propagated (faster than light) from Alice's apparatus to make Bob's positron assume a definite spin in the appropriate axis.

Bell's theorem
In 1964, John Stewart Bell published a paper investigating the puzzling situation at that time: on one hand, the EPR paradox purportedly showed that quantum mechanics was nonlocal, and suggested that a hidden-variable theory could heal this nonlocality. On the other hand, David Bohm had recently developed the first successful hidden-variable theory, but it had a grossly nonlocal character. Bell set out to investigate whether it was indeed possible to solve the nonlocality problem with hidden variables, and found out that first, the correlations shown in both EPR's and Bohm's versions of the paradox could indeed be explained in a local way with hidden variables, and second, that the correlations shown in his own variant of the paradox couldn't be explained by any local hidden-variable theory. This second result became known as the Bell theorem.

To understand the first result, consider the following toy hidden-variable theory introduced later by J.J. Sakurai: in it, quantum spin-singlet states emitted by the source are actually approximate descriptions for "true" physical states possessing definite values for the z-spin and x-spin. In these "true" states, the positron going to Bob always has spin values opposite to the electron going to Alice, but the values are otherwise completely random. For example, the first pair emitted by the source might be "(+z, −x) to Alice and (−z, +x) to Bob", the next pair "(−z, −x) to Alice and (+z, +x) to Bob", and so forth. Therefore, if Bob's measurement axis is aligned with Alice's, he will necessarily get the opposite of whatever Alice gets; otherwise, he will get "+" and "−" with equal probability.

Bell showed, however, that such models can only reproduce the singlet correlations when Alice and Bob make measurements on the same axis or on perpendicular axes. As soon as other angles between their axes are allowed, local hidden-variable theories become unable to reproduce the quantum mechanical correlations. This difference, expressed using inequalities known as "Bell's inequalities", is in principle experimentally testable. After the publication of Bell's paper, a variety of experiments to test Bell's inequalities were carried out, notably by the group of Alain Aspect in the 1980s; all experiments conducted to date have found behavior in line with the predictions of quantum mechanics. The present view of the situation is that quantum mechanics flatly contradicts Einstein's philosophical postulate that any acceptable physical theory must fulfill "local realism". The fact that quantum mechanics violates Bell inequalities indicates that any hidden-variable theory underlying quantum mechanics must be non-local; whether this should be taken to imply that quantum mechanics itself is non-local is a matter of continuing debate.

Steering
Inspired by Schrödinger's treatment of the EPR paradox back in 1935, Howard M. Wiseman et al. formalised it in 2007 as the phenomenon of quantum steering. They defined steering as the situation where Alice's measurements on a part of an entangled state steer Bob's part of the state. That is, Bob's observations cannot be explained by a local hidden state model, where Bob would have a fixed quantum state in his side, that is classically correlated but otherwise independent of Alice's.

Locality
Locality has several different meanings in physics. EPR describe the principle of locality as asserting that physical processes occurring at one place should have no immediate effect on the elements of reality at another location. At first sight, this appears to be a reasonable assumption to make, as it seems to be a consequence of special relativity, which states that energy can never be transmitted faster than the speed of light without violating causality; however, it turns out that the usual rules for combining quantum mechanical and classical descriptions violate EPR's principle of locality without violating special relativity or causality. Causality is preserved because there is no way for Alice to transmit messages (i.e., information) to Bob by manipulating her measurement axis. Whichever axis she uses, she has a 50% probability of obtaining "+" and 50% probability of obtaining "−", completely at random; according to quantum mechanics, it is fundamentally impossible for her to influence what result she gets. Furthermore, Bob is able to perform his measurement only once: there is a fundamental property of quantum mechanics, the no-cloning theorem, which makes it impossible for him to make an arbitrary number of copies of the electron he receives, perform a spin measurement on each, and look at the statistical distribution of the results. Therefore, in the one measurement he is allowed to make, there is a 50% probability of getting "+" and 50% of getting "−", regardless of whether or not his axis is aligned with Alice's.

As a summary, the results of the EPR thought experiment do not contradict the predictions of special relativity. Neither the EPR paradox nor any quantum experiment demonstrates that superluminal signaling is possible; however, the principle of locality appeals powerfully to physical intuition, and Einstein, Podolsky and Rosen were unwilling to abandon it. Einstein derided the quantum mechanical predictions as "spooky action at a distance". The conclusion they drew was that quantum mechanics is not a complete theory.

Mathematical formulation
Bohm's variant of the EPR paradox can be expressed mathematically using the quantum mechanical formulation of spin. The spin degree of freedom for an electron is associated with a two-dimensional complex vector space V, with each quantum state corresponding to a vector in that space. The operators corresponding to the spin along the x, y, and z direction, denoted Sx, Sy, and Sz respectively, can be represented using the Pauli matrices: $$ S_x = \frac{\hbar}{2} \begin{bmatrix} 0 &  1 \\ 1 &  0 \end{bmatrix}, \quad S_y = \frac{\hbar}{2} \begin{bmatrix} 0 & -i \\ i & 0 \end{bmatrix}, \quad S_z = \frac{\hbar}{2} \begin{bmatrix} 1 & 0 \\ 0 & -1 \end{bmatrix}, $$ where $$\hbar$$ is the reduced Planck constant (or the Planck constant divided by 2π).

The eigenstates of Sz are represented as $$ \left|+z\right\rangle \leftrightarrow \begin{bmatrix}1\\0\end{bmatrix}, \quad \left|-z\right\rangle \leftrightarrow \begin{bmatrix}0\\1\end{bmatrix} $$ and the eigenstates of Sx are represented as $$ \left|+x\right\rangle \leftrightarrow \frac{1}{\sqrt{2}} \begin{bmatrix}1\\1\end{bmatrix}, \quad \left|-x\right\rangle \leftrightarrow \frac{1}{\sqrt{2}} \begin{bmatrix}1\\-1\end{bmatrix}. $$

The vector space of the electron-positron pair is $$ V \otimes V $$, the tensor product of the electron's and positron's vector spaces. The spin singlet state is $$ \left|\psi\right\rangle = \frac{1}{\sqrt{2}} \biggl(   \left|+z\right\rangle \otimes \left|-z\right\rangle -    \left|-z\right\rangle \otimes \left|+z\right\rang  \biggr), $$ where the two terms on the right hand side are what we have referred to as state I and state II above.

From the above equations, it can be shown that the spin singlet can also be written as $$ \left|\psi\right\rangle = -\frac{1}{\sqrt{2}} \biggl(   \left|+x\right\rangle \otimes \left|-x\right\rangle -    \left|-x\right\rangle \otimes \left|+x\right\rangle  \biggr), $$ where the terms on the right hand side are what we have referred to as state Ia and state IIa.

To illustrate the paradox, we need to show that after Alice's measurement of Sz (or Sx), Bob's value of Sz (or Sx) is uniquely determined and Bob's value of Sx (or Sz) is uniformly random. This follows from the principles of measurement in quantum mechanics. When Sz is measured, the system state $$|\psi\rangle$$ collapses into an eigenvector of Sz. If the measurement result is +z, this means that immediately after measurement the system state collapses to $$ \left| +z \right\rangle \otimes \left| -z \right\rangle = \left| +z \right\rangle \otimes \frac{\left| +x \right\rangle - \left| -x \right\rangle}{\sqrt2}.$$

Similarly, if Alice's measurement result is −z, the state collapses to $$ \left|-z\right\rangle \otimes \left|+z\right\rangle = \left| -z \right\rangle \otimes \frac{\left| +x \right\rangle + \left| -x \right\rangle}{\sqrt2}.$$ The left hand side of both equations show that the measurement of Sz on Bob's positron is now determined, it will be −z in the first case or +z in the second case. The right hand side of the equations show that the measurement of Sx on Bob's positron will return, in both cases, +x or -x with probability 1/2 each.

Selected papers

 * A. Fine, Do Correlations need to be explained?, in Philosophical Consequences of Quantum Theory: Reflections on Bell's Theorem, edited by Cushing & McMullin (University of Notre Dame Press, 1986).
 * M. Mizuki, A classical interpretation of Bell's inequality. Annales de la Fondation Louis de Broglie 26 683 (2001)
 * P. Pluch, "Theory for Quantum Probability", PhD Thesis University of Klagenfurt (2006)
 * A. Fine, Do Correlations need to be explained?, in Philosophical Consequences of Quantum Theory: Reflections on Bell's Theorem, edited by Cushing & McMullin (University of Notre Dame Press, 1986).
 * M. Mizuki, A classical interpretation of Bell's inequality. Annales de la Fondation Louis de Broglie 26 683 (2001)
 * P. Pluch, "Theory for Quantum Probability", PhD Thesis University of Klagenfurt (2006)
 * M. Mizuki, A classical interpretation of Bell's inequality. Annales de la Fondation Louis de Broglie 26 683 (2001)
 * P. Pluch, "Theory for Quantum Probability", PhD Thesis University of Klagenfurt (2006)
 * P. Pluch, "Theory for Quantum Probability", PhD Thesis University of Klagenfurt (2006)

Books

 * Bell, John S. (1987). Speakable and Unspeakable in Quantum Mechanics. Cambridge University Press. ISBN 0-521-36869-3.
 * Fine, Arthur (1996). The Shaky Game: Einstein, Realism and the Quantum Theory. 2nd ed. Univ. of Chicago Press.
 * Gribbin, John (1984). In Search of Schrödinger's Cat. Black Swan. ISBN 978-0-552-12555-0
 * Leaderman, Leon; Teresi, Dick (1993). The God Particle: If the Universe Is the Answer, What Is the Question? Houghton Mifflin Company, pp. 21, 187–189.
 * Selleri, Franco (1988). Quantum Mechanics Versus Local Realism: The Einstein–Podolsky–Rosen Paradox. New York: Plenum Press. ISBN 0-306-42739-7.

title: Einstein–Podolsky–Rosen paradox


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Talk:Einstein–Podolsky–Rosen paradox

Section under "the crux of the matter" is wrong
The section under "the crux of the matter" is wrong. By only measuring the x or z axis you cannot distinguish between a classical system with hidden variables and a quantum system. One has to measure at 45 degrees also. The description is wrong.

Sorry, I meant to put this somewhere else, but I do not know how to delete this.

Observer as Variable
The impact of consciousness is unquestioned, how much more abstract is consciousness greater will its power both in size and complexity?

particles are not states...
In the first line of description of the EPR experiment it is currently written:
 * The thought experiment involves a pair of particles prepared in what would later become known as an entangled state.

I think it is misleading to link "particles" to "states". In quantum mechanics (not quantum field theory), a particle is in a state or it has a state, but it is not a state. In addition, there is a single quantum state not a pair of them involved in the EPR thought experiment. Since undid my change in the article, I'm starting the discussion here to come to a better formulation. I think it's uncontroversial that
 * The thought experiment involves a pair of particles prepared in what would later become known as an entangled state.

The only question is where to put the wikilinks. I object to linking "particles" to "quantum state" since the two are very different objects; if we don't and link "entangled state" to "quantum entanglement" then the concept of quantum state doesn't appear in the sentence (which is why I linked "entangled" to entanglement and "state" to "quantum state"). An alternative could be:
 * The thought experiment involves a pair of particles prepared in a state of the kind that would later become known as an entangled state.

Would that be ok? --Qcomp (talk) 09:26, 2 September 2023 (UTC)

 * Please check the history, your version is the current one. Jähmefyysikko (talk) 09:36, 2 September 2023 (UTC)
 * @Qcomp thank you for this great explanation. my change was an error which I undid immediately afterwards. I'm sorry for the mistake and confusion. Johnjbarton (talk) 15:05, 2 September 2023 (UTC)
 * ok, sorry for the fuss - I got the notice about the revert and didn't notice that it had already been undone again. Thanks to all for caring about the article. --Qcomp (talk) 15:13, 2 September 2023 (UTC)

Uncertainty principle
The article states, "... it is impossible to measure both the momentum and the position of particle B exactly; however, it is possible to measure the exact position of particle A." This is an error. The uncertainty principle also says it is impossible to measure the exact position of particle A! The idea that knowing the position of particle A allows calculation of the exact position of particle B is also highly suspect. Please, would some Quantum Mechanics guru (which I am not) check this article carefully. Meanwhile, I will take the whole article with a grain of salt. Wcmead3 (talk) Wcmead3 (talk) 03:13, 23 February 2024 (UTC)

 * You claim:
 * "The uncertainty principle also says it is impossible to measure the exact position of particle A!"
 * Do you have a source for this assertion? If not then I think the article is not in error.
 * If one places a small metal cup in the area where one expects particle A, then the detection of a particle in the cup fixes its position. Such a cup cannot be made arbitrarily small, but the QM theory discussed in the EPR article is not about such practicality. Rather it is about the position operator, which can be arbitrarily exact. Johnjbarton (talk) 03:58, 23 February 2024 (UTC)
 * For myself, I'd regard having to divide Planck's constant by zero to get the uncertainty in momentum after making my perfectly precise position measurement as pretty decisive. Surely it it means at the very least that if a particle's position is precisely known, the uncertainty in its momentum is undefined. So we can approach perfect measurement arbitrarily closely, watching the uncertainty in the momentum tend to infinity as we do so, but things break down once we get to zero uncertainty. Musiconeologist (talk) 23:21, 22 March 2024 (UTC)
 * The uncertainty principle is about measurements as it says in this article as well. Johnjbarton (talk) 23:43, 22 March 2024 (UTC)
 * @Johnjbarton Well yes, but it states a mathematical relationship between their uncertainties, which becomes a contradictory one if either uncertainty is zero. Musiconeologist (talk) 23:54, 22 March 2024 (UTC)
 * Putting it more worryingly, if ΔpΔx=h/2π (or is it 4π? It's too many years since I learnt this stuff) and Δx=0, then h=0. But it's not. Musiconeologist (talk) 23:48, 22 March 2024 (UTC)
 * Well is physics not math and its greater than rather that equal to, so we can rest easy. Johnjbarton (talk) 00:22, 23 March 2024 (UTC)
 * @Johnjbarton Ah of course. Though multiplying two things one of which is zero to get an answer greater than h/2π still bothers me. It still seems to me to imply straight away that Δx ≠ 0, i.e. x can't be precisely measured. Anyway my guess is that this is where the statement about the impossibility of a perfect measurement comes from. But I suppose it might be reasonable to say that since the relation breaks down for a perfect measurement, it can't be applied to one and therefore doesn't rule it out. But I only learnt the electronic engineering version of this stuff, and it was a few decades ago . . . Musiconeologist (talk) 01:21, 23 March 2024 (UTC)

The "Paradox" paper
" According to Heisenberg's uncertainty principle, it is impossible to measure both the momentum and the position of particle B exactly; however, it is possible to measure the exact position of particle A. By calculation, therefore, with the exact position of particle A known, the exact position of particle B can be known. Alternatively, the exact momentum of particle A can be measured, so the exact momentum of particle B can be worked out. "

Well, no. As per Heisenberg's uncertainty, no measurement is absolute, neither combined nor separate. There are always digits missing, and thus exactness is never reached. However, both can be approximated at nearly the same approximated time, which all measurements are. Hence, no true predictions are possible, and yet approximations are, which will invariably vary over the entire extrapolation, increasing in variablility over the main components, time and distance, if and when these apply.

title: Talk:Einstein–Podolsky–Rosen paradox


text: Talk:JavaScript

title: Talk:JavaScript


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Encapsulation

Encapsulation may refer to:

Chemistry

 * Molecular encapsulation, in chemistry, the confinement of an individual molecule within a larger molecule
 * Micro-encapsulation, in material science, the coating of microscopic particles with another material

Biology

 * Cell encapsulation, technology made to overcome the existing problem of graft rejection in tissue engineering applications

Computing and electronics

 * An alternate term for conformal coating or potting, which protects electronic components
 * Encapsulation (networking), the process of adding control information as it passes through the layered model
 * Encapsulation (computer programming), the combination of program code and data, and/or restriction (hide) of access to data except through dedicated code

כימוס

title: Encapsulation


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Ethnologue

Ethnologue: Languages of the World is an annual reference publication in print and online that provides statistics and other information on the living languages of the world. It is the world's most comprehensive catalogue of languages. It was first issued in 1951, and is now published by SIL International, an American evangelical Christian non-profit organization.

Overview and content
Ethnologue has been published by SIL International (formerly known as the Summer Institute of Linguistics), a Christian linguistic service organization with an international office in Dallas, Texas. The organization studies numerous minority languages to facilitate language development, and to work with speakers of such language communities in translating portions of the Bible into their languages. Despite the Christian orientation of its publisher, Ethnologue is not ideologically or theologically biased.

Ethnologue includes alternative names and autonyms, the number of L1 and L2 speakers, language prestige, domains of use, literacy rates, locations, dialects, language classification, linguistic affiliations, typology, language maps, country maps, publication and use in media, availability of the Bible in each language and dialect described, religious affiliations of speakers, a cursory description of revitalization efforts where reported, intelligibility and lexical similarity with other dialects and languages, writing scripts, an estimate of language viability using the Expanded Graded Intergenerational Disruption Scale (EGIDS), and bibliographic resources. Coverage varies depending on languages. For instance, as of 2008, information on word order was present for 15% of entries while religious affiliations were mentioned for 38% of languages. According to Lyle Campbell "language maps are highly valuable" and most country maps are of high quality and user-friendly.

Ethnologue gathers information from SIL's thousands of field linguists, surveys done by linguists and literacy specialists, observations of Bible translators, and crowdsourced contributions. SIL's field linguists use an online collaborative research system to review current data, update it, or request its removal. SIL has a team of editors by geographical area who prepare reports to Ethnologue's general editor. These reports combine opinions from SIL area experts and feedback solicited from non-SIL linguists. Editors have to find compromises when opinions differ. Most of SIL's linguists have taken three to four semesters of graduate linguistics courses, and half of them have a master's degree. They're trained by 300 PhD linguists in SIL. The determination of what characteristics define a single language depends upon sociolinguistic evaluation by various scholars; as the preface to Ethnologue states, "Not all scholars share the same set of criteria for what constitutes a 'language' and what features define a 'dialect'." The criteria used by Ethnologue are mutual intelligibility and the existence or absence of a common literature or ethnolinguistic identity. The number of languages identified has been steadily increasing, from 5,445 in the 10th edition (in 1984) to 6,909 in the 16th (in 2009), partly due to governments according designation as languages to mutually intelligible varieties and partly due to SIL establishing new Bible translation teams. Ethnologue codes were used as the base to create the new ISO 639-3 international standard. Since 2007, Ethnologue relies only on this standard, administered by SIL International, to determine what is listed as a language.

In addition to choosing a primary name for a language, Ethnologue provides listings of other name(s) for the language and any dialects that are used by its speakers, government, foreigners and neighbors. Also included are any names that have been commonly referenced historically, regardless of whether a name is considered official, politically correct or offensive; this allows more complete historic research to be done. These lists of names are not necessarily complete.

History
Ethnologue was founded in 1951 by Richard S. Pittman and was initially focused on minority languages, to share information on Bible translation needs. The first edition included information on 46 languages. Hand-drawn maps were introduced in the fourth edition (1953). The seventh edition (1969) listed 4,493 languages. In 1971, Ethnologue expanded its coverage to all known languages of the world.

Ethnologue database was created in 1971 at the University of Oklahoma under a grant from the National Science Foundation. In 1974 the database was moved to Cornell University. Since 2000, the database has been maintained by SIL International in their Dallas headquarters. In 1997 (13th edition), the website became the primary means of access.

In 1984, Ethnologue released a three-letter coding system, called an 'SIL code', to identify each language that it described. This set of codes significantly exceeded the scope of other existing standards, e.g. ISO 639-1 and ISO 639-2.

The 14th edition, published in 2000, included 7,148 language codes. In 2002, Ethnologue was asked to work with the International Organization for Standardization (ISO) to integrate its codes into a draft international standard. Ethnologue codes have then been adopted by ISO as the international standard, ISO 639-3. The 15th edition of Ethnologue was the first edition to use this standard. This standard is now administered separately from Ethnologue. SIL International is the registration authority for languages names and codes, according to rules established by ISO. Since then Ethnologue relies on the standard to determine what is listed as a language. In only one case, Ethnologue and the ISO standards treat languages slightly differently. ISO 639-3 considers Akan to be a macrolanguage consisting of two distinct languages, Twi and Fante, whereas Ethnologue considers Twi and Fante to be dialects of a single language (Akan), since they are mutually intelligible. This anomaly resulted because the ISO 639-2 standard has separate codes for Twi and Fante, which have separate literary traditions, and all 639-2 codes for individual languages are automatically part of 639-3, even though 639-3 would not normally assign them separate codes.

In 2014, with the 17th edition, Ethnologue introduced a numerical code for language status using a framework called EGIDS (Expanded Graded Intergenerational Disruption Scale), an elaboration of Fishman's GIDS (Graded Intergenerational Disruption Scale). It ranks a language from 0 for an international language to 10 for an extinct language, i.e. a language with which no-one retains a sense of ethnic identity.

In 2015, SIL's funds decreased and in December 2015, Ethnologue launched a metered paywall to cover its cost, as it is financially self-sustaining. Users in high-income countries who wanted to refer to more than seven pages of data per month had to buy a paid subscription. The 18th edition released that year included a new section on language policy country by country.

In 2016, Ethnologue added date about language planning agencies to the 19th edition.

As of 2017, Ethnologue 's 20th edition described 237 language families including 86 language isolates and six typological categories, namely sign languages, creoles, pidgins, mixed languages, constructed languages, and as yet unclassified languages.

The early focus of the Ethnologue was on native use (L1) but was gradually expanded to cover L2 use as well.

In 2019, Ethnologue disabled trial views and introduced a hard paywall to cover its nearly $1 million in annual operating costs (website maintenance, security, researchers, and SIL's 5,000 field linguists). Subscriptions start at $480 per person per year, while full access costs $2,400 per person per year. Users in low and middle-income countries as defined by the World Bank are eligible for free access and there are discounts for libraries and independent researchers. Subscribers are mostly institutions: 40% of the world's top 50 universities subscribe to Ethnologue, and it is also sold to business intelligence firms and Fortune 500 companies. The introduction of the paywall was harshly criticized by the community of linguists who rely on Ethnologue to do their work and cannot afford the subscription The same year, Ethnologue launched its contributor program to fill gaps and improve accuracy, allowing contributors to submit corrections and additions and to get a complimentary access to the website. Ethnologue 's editors gradually review crowdsourced contributions before publication. As 2019 was the International Year of Indigenous Languages, this edition focused on language loss: it added the date when last fluent speaker of the language died, standardized the age range of language users, and improved the EGIDS estimates.

In 2020, the 23rd edition listed 7,117 living languages, an increase of 6 living languages from the 22nd edition. In this edition, Ethnologue expanded its coverage of immigrant languages: previous editions only had full entries for languages considered to be "established" within a country. From this edition, Ethnologue includes data about first and second languages of refugees, temporary foreign workers and immigrants.

In 2021, the 24th edition had 7,139 modern languages, an increase of 22 living languages from the 23rd edition. Editors especially improved data about language shift in this edition.

In 2022, the 25th edition listed a total of 7,151 living languages, an increase of 12 living languages from the 24th edition. This edition specifically improved the use of languages in education.

In 2023, the 26th edition listed a total of 7,168 living languages, an increase of 17 living languages from the 25th edition.

In 2024, the 27th edition listed a total of 7,164 living languages, a decrease of 4 living languages from the 26th edition.

Reception, reliability, and use
In 1986, William Bright, then editor of the journal Language, wrote of Ethnologue that it "is indispensable for any reference shelf on the languages of the world". The 2003 International Encyclopedia of Linguistics described Ethnologue as "a comprehensive listing of the world's languages, with genetic classification", and follows Ethnologue's classification. In 2005, linguists Lindsay J. Whaley and Lenore Grenoble considered that Ethnologue "continues to provide the most comprehensive and reliable count of numbers of speakers of the world's languages", still they recognize that "individual language surveys may have far more accurate counts for a specific language, but The Ethnologue is unique in bringing together speaker statistics on a global scale". In 2006, computational linguists John C. Paolillo and Anupam Das conducted a systematic evaluation of available information on language populations for the UNESCO Institute for Statistics. They reported that Ethnologue and Linguasphere were the only comprehensive sources of information about language populations and that Ethnologue had more specific information. They concluded that: "the language statistics available today in the form of the Ethnologue population counts are already good enough to be useful" According to linguist William Poser, Ethnologue was, as of 2006, the "best single source of information" on language classification. In 2008 linguists Lyle Campbell and Verónica Grondona highly commended Ethnologue in Language. They described it as a highly valuable catalogue of the world's languages that "has become the standard reference" and whose "usefulness is hard to overestimate". They concluded that Ethnologue was "truly excellent, highly valuable, and the very best book of its sort available."

In a review of Ethnologue 's 2009 edition in Ethnopolitics, Richard O. Collin, professor of politics, noted that "Ethnologue has become a standard resource for scholars in the other social sciences: anthropologists, economists, sociologists and, obviously, sociolinguists". According to Collin, Ethnologue is "stronger in languages spoken by indigenous peoples in economically less-developed portions of the world" and "when recent in-depth country-studies have been conducted, information can be very good; unfortunately [...] data are sometimes old".

In 2012, linguist Asya Pereltsvaig described Ethnologue as "a reasonably good source of thorough and reliable geographical and demographic information about the world's languages". She added in 2021 that its maps "are generally fairly accurate although they often depict the linguistic situation as it once was or as someone might imagine it to be but not as it actually is". Linguist George Tucker Childs wrote in 2012 that: "Ethnologue is the most widely referenced source for information on languages of the world", but he added that regarding African languages, "when evaluated against recent field experience [Ethnologue] seems at least out of date". In 2014, Ethnologue admitted that some of its data was out-of-date and switched from a four-year publication cycle (in print and online) to yearly online updates.

In 2017, Robert Phillipson and Tove Skutnabb-Kangas described Ethnologue as "the most comprehensive global source list for (mostly oral) languages". According to the 2018 Oxford Research Encyclopedia of Linguistics, Ethnologue is a "comprehensive, frequently updated [database] on languages and language families'. According to quantitative linguists Simon Greenhill, Ethnologue offers, as of 2018, "sufficiently accurate reflections of speaker population size". Linguists Lyle Campbell and Kenneth Lee Rehg wrote in 2018 that Ethnologue was "the best source that list the non-endangered languages of the world". Lyle Campbell and Russell Barlow also noted that the 2017 edition of Ethnologue "improved [its] classification markedly". They note that Ethnologue 's genealogy is similar to that of the World Atlas of Language Structures (WALS) but different from that of the Catalogue of Endangered Languages (ELCat) and Glottolog. Linguist Lisa Matthewson commented in 2020 that Ethnologue offers "accurate information about speaker numbers". In a 2021 review of Ethnologue and Glottolog, linguist Shobhana Chelliah noted that "For better or worse, the impact of the site is indeed considerable. [...] Clearly, the site has influence on the field of linguistics and beyond." She added that she, among other linguists, integrated Ethnologue in her linguistics classes."

The Encyclopedia of Language and Linguistics uses Ethnologue as its primary source for the list of languages and language maps. According to linguist Suzanne Romaine, Ethnologue is also the leading source for research on language diversity. According to The Oxford Handbook of Language and Society, Ethnologue is "the standard reference source for the listing and enumeration of Endangered Languages, and for all known and "living" languages of the world"." Similarly, linguist David Bradley describes Ethnologue as "the most comprehensive effort to document the level of endangerment in languages around the world." The US National Science Foundation uses Ethnologue to determine which languages are endangered. According to Hammarström et al., Ethnologue is, as of 2022, one of the three global databases documenting language endangerment with the Atlas of the World's Languages in Danger and the Catalogue of Endangered Languages (ELCat). The University of Hawaii Kaipuleohone language archive uses Ethnologue 's metadata as well. The World Atlas of Language Structures uses Ethnologue 's genealogical classification. The Rosetta Project uses Ethnologue 's language metadata.

In 2005, linguist Harald Hammarström wrote that Ethnologue was consistent with specialist views most of the time and was a catalog "of very high absolute value and by far the best of its kind". In 2011, Hammarström created Glottolog in response to the lack of a comprehensive language bibliography, especially in Ethnologue. In 2015, Hammarström reviewed the 16th, 17th, and 18th editions of Ethnologue and described the frequent lack of citations as its only "serious fault" from a scientific perspective. He concluded: "Ethnologue is at present still better than any other nonderivative work of the same scope. [It] is an impressively comprehensive catalogue of world languages, and it is far superior to anything else produced prior to 2009. In particular, it is superior by virtue of being explicit." According to Hammarström, as of 2016, Ethnologue and Glottolog are the only global-scale continually maintained inventories of the world's languages. The main difference is that Ethnologue includes additional information (such as speaker numbers or vitality) but lacks systematic sources for the information given. In contrast, Glottolog provides no language context information but points to primary sources for further data. Contrary to Ethnologue, Glottolog does not run its own surveys, but it uses Ethnologue as one of its primary sources. As of 2019, Hammarström uses Ethnologue in his articles, noting that it "has (unsourced, but) detailed information associated with each speech variety, such as speaker numbers and map location". In response to feedback about the lack of references, Ethnologue added in 2013 a link on each language to language resources from the Open Language Archives Community (OLAC) Ethnologue acknowledges that it rarely quotes any source verbatim but cites sources wherever specific statements are directly attributed to them, and corrects missing attributions upon notification. The website provides a list of all of the references cited. In her 2021 review, Shobhana Chelliah noted that Glottolog aims to be better than Ethnologue in language classification and genetic and areal relationships by using linguists' original sources.

Editions
Starting with the 17th edition, Ethnologue has been published every year, on February 21, which is International Mother Language Day.

title: Ethnologue