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Continue Aspect of history This article may contain original research. Please improve it by checking the claims made and adding links. Applications consisting only of original research must be removed. (January 2018) (Learn how and when to delete this template message) Cryptography, the use of codes and to protect secrets, began thousands of years ago. Until recent decades, it was a story about what might be called classical cryptography - that is, techniques that use pen and paper, or perhaps simple mechanical means. In the early 20th century, the invention of sophisticated mechanical and electromechanical machines, such as the rotary machine, provided more sophisticated and efficient encryption tools; and the subsequent introduction of electronics and computing has allowed for the development of more complex circuits, most of which are completely unprocessed for pen and paper. In parallel with the development of cryptography is the development of cryptoanalysis - hacking codes and ciphers. Detection and application, early on, to read encrypted messages, sometimes changed the course of history. Thus, the telegram provoked the United States to enter ; and allied reading of the ciphers of Nazi shortening world war II, in some estimates as much as two years. Until the 1960s, safe cryptography was largely the prerogative of governments. Two events have since brought him directly into the public domain: the creation of the Public Encryption Standard (DES), and the invention of public cryptography. Ancient , an early device for encryption. The earliest known use of cryptography is found in non-standard hieroglyphics carved into the wall of the tomb from the Old Kingdom of Egypt around 1900 BC However, these are not serious attempts of secret messages, but attempts of riddles, intrigues or even entertainment for literate viewers. Some clay tablets from Mesopotamia are somewhat later explicitly intended to protect information - one from around 1500 BC was found to encrypt the artisan's recipe for pottery glaze, presumably commercially valuable. In addition, Jewish scientists used simple monoalfabetic replacement ciphers (such as the ) starting, perhaps from about 600 BC to 500 BC, in India around 400 BC to 200 AD, or the art of understanding writing in cipher, and the spelling of words was specially documented in Kama Sutra with the aim of communicating between lovers. It's also probably a simple replacement cipher. Parts of the Egyptian demotic Greek magical papiri were written with a cipher. The ancient Greeks are said to know the ciphers. Scytale was Spartan military, but it is not known definitively whether there was a scytale for encryption, authentication or avoiding bad omens in speech. Herodotus tells us about secret messages physically hidden under wax on wooden plates or as a tattoo on a slave's head, hidden from outgrown hairs, although they are not properly examples of cryptography per se, since the message is only known to be read directly; it's known as . Another Greek method was developed by Polybius (now called ). The Romans knew something about cryptography (such as Caesar's cipher and its variations). Medieval cryptography The first page of al-Kindi's manuscript on cryptographic messages, containing the first descriptions of cryptoanalysis and frequency analysis. See also: The classic cipher and manuscript of Voynich notes in Codebreakers that modern cryptology originated among Arabs, the first people to systematically document cryptoanalytic methods. Al-Khalil (717-786) wrote the Book of Cryptographic Messages, which contains the first use of permutations and combinations to list all possible Arabic words with and without vowels. The invention of the frequency analysis method to crack monoalfabetic ciphers replacing Al-Kindi, an Arab mathematician, around 800 AD, proved to be the most significant crypto-analytical progress before World War II. Al-Kindi wrote a book on cryptography called Risalah fi Istikhraj al-Mu'amma (Manuscript for the Decipheric Messages), in which he described the first cryptoanalytic methods, including polyalphabetic ciphers, cipher classification, Arabic phonetics and syntax, and most importantly, gave the first descriptions on frequency analysis. It also covered methods of enciference, cryptoanalysis of some bonds and statistical analysis of letters and combinations of letters in Arabic. An important contribution by Ibn Adlan (1187-1268) was the sample size for the use of frequency analysis. In early medieval England, between 800 and 1100, replacement ciphers were often used by scribes as a playful and clever way of entangling notes, puzzles and colophons. The ciphers are usually quite simple, but sometimes they deviate from the usual pattern, adding to their complexity, and perhaps also to their complexity. During this period, the West had vital and significant cryptographic experiments. Ahmad al-Allkashandi (1355-1418) wrote Subh al-Sha, a 14-volume encyclopedia that included a section on cryptology. This information was attributed to Ibn al-Durayhimu, who lived from 1312 AD to 1361, but whose cryptography work was lost. The list of ciphers in this work included both substitution and transposition and a cipher with multiple substitutions for each letter of simple text (later called homophonic replacement). Also traced Ibn al-Durayhim is an exposition and worked an example of cryptoanalysis, including the use of tables of letter frequencies and sets of letters that can not happen together in one word. The earliest example of the homophonic replacement cipher is the cipher used by the Duke of Mantua in the early 1400s. The cipher is ahead of time because it combines monoalfabetic and polyalphabetic features. Essentially, all ciphers remained vulnerable to the cryptoanalytic technique of frequency analysis until the development of polyalphabet cipher, and many remained so after that. The was most clearly explained by Leon Battista Alberti around 1467 AD, for which he was called the father of Western cryptology. Johannes Tritemius in his work Polygraphia invented the , the most important component of the cipher Vigener. Trithemium also wrote a steganography. French cryptographer Blaise de Vigener developed a practical polyalphabetic system that bears his name, the Cipher Cigener. In Europe, cryptography has become (secretly) more important as a result of political competition and religious revolution. For example, in Europe during and after the Renaissance, citizens of various Italian states, including the pontifical states and the Roman Catholic Church, were responsible for the rapid spread of cryptographic methods, few of which reflected the understanding (or even knowledge) of Alberti's polyalphabetic progression. Advanced ciphers, even after Alberti, were not as advanced as their inventors/developers/users claimed (and probably even they themselves believed). They often broke down. This over- optimism may be inherent in cryptography, because it was then - and remains today - difficult in principle to know how vulnerable your own system is. In the absence of knowledge, guesswork and hope are predictably common. Cryptography, cryptanalysis and betrayal of the secret agent/courier were featured in The Babington story during the reign of queen Elizabeth I, which led to the execution of Mary, queen of Scotland. Robert Hook suggested in the chapter of Dr. Dee's Book of Spirits that John Dee used triteian steganography to hide his communication with queen Elizabeth I. He and his family created what is known as the because it remained unresolved from its original use until 1890, when the French military cryptoanalyst Etienne Baseri decided it. The encrypted message of of the Man in the Iron Mask (deciphered shortly before 1900 by Etienne Bazeri) shed some, unfortunately, neo-icom light on the the personality of this real, if legendary and unhappy, prisoner. Outside Europe, after the Mongols brought the End of the Islamic Golden Age to an end, cryptography remained relatively undeveloped. Cryptography in Japan does not seem to have been used until about 1510, and advanced methods were not known until after the discovery of the country in the West, dating back to the 1860s. Cryptography from 1800 to World War II Home article: World War I cryptography Although cryptography has a long and complex history, it was not until the 19th century that it developed nothing more than special approaches to encryption or cryptoanalysis (the science of finding weaknesses in ). Examples include Charles Babbig's work of the Crimean War era on the mathematical cryptoanalysis of polyalphabetic ciphers, reworked and published a little later by Prussian Friedrich Kasischi. Understanding cryptography at this time usually consisted of having a hard time winning the rules of the thumb; see, for example, the cryptographic works of Augustin Kerkhoff in the 19th century. Edgar Allan Poe used systematic methods to solve ciphers in the 1840s. Specifically, he posted a notice of his abilities in the Philadelphia newspaper Alexander's Weekly (Express) Messenger, inviting him to submit ciphers, of which he began to address almost all. Its success has caused a public outcry for months. He later wrote an essay on cryptography techniques that proved useful as an introduction to aspiring British cryptoanalysts trying to break German codes and ciphers during World War I, and the famous story, The Golden Bug, in which cryptoanalysis was an outstanding element. Cryptography, and its misuse, were involved in The Execution of Mata and in Dreyfus's conviction and imprisonment, both in the early 20th century. Cryptographers were also involved in exposing the machinations that led to the Dreyfus case; Mata, on the other hand, was shot. During World War I, Admiralty Room 40 violated German naval codes and played an important role in several naval battles during the war, in particular the discovery of large German sorties in the North Sea that led to the battles of Dogger Bank and Jutland when the British fleet was sent to intercept them. His most important contribution, however, was probably in the transcription of a telegram from the German Ministry of Foreign Affairs sent through Washington to his Ambassador Heinrich von Eckardt in Mexico, who was instrumental in bringing the United States to war. In 1917, Gilbert Vernam offered a teleprinter cipher, in which a previously prepared key stored on a paper tape combined character behind a character with a simple text message to create a cipher. This has led to the development of electromechanical devices in the machine cipher, and to the only indestructible cipher, a disposable time bar. In the 1920s, Polish naval officers Japanese military with and development cipher. Mathematical methods were developed in the period before World War II (particularly in William F. Friedman's use of statistical methods for cryptoanalysis and cipher development and in the initial hacking by Marian Reevsky in the German army version of the Enigma system in 1932). Cryptography of World War II See also: Cryptography of world war II, cryptanalysis and a list of cryptographers was widely used by ; its cryptoanalysis by allies provided vital ultraintelligence information. By The Second World War, mechanical and electromechanical encrypted machines were widely used, although such machines were impractical - code books and manual systems continued. Big successes have been made in both cipher design and cryptanalysis, all in secret. Information about this period began to be declassified, as the official British 50-year period of secrecy began, as American archives slowly opened, and various memoirs and articles appeared. Germany Germans have made heavy use, in several variants, of an electromechanical rotary machine known as enigma. Mathematician of the Polish in December 1932 developed a detailed structure of the German Army Enigma, using mathematics and limited documentation provided by the captain of French . According to historian David Kahn, this was the greatest breakthrough in cryptoanalysis in a thousand years or more. Rejewski and his colleagues in the Mathematical Cipher Bureau, Yeji Roeutski and Henrik Sigalski, continued to read Enigma and keep up with the evolution of the components and procedures for the German army machine. As the resources of the strained due to the changes made by the Germans, and as the war loomed, the Bureau of Ciphers on the instructions of the on July 25, 1939 in initiated the deciphering of French and British intelligence in the secrets of deciphering Enigma. Shortly after the German invasion of on 1 September 1939, key personnel of the Cipher Bureau were evacuated to the south-east; On September 17, when the attacked Poland from the east, they moved to Romania. From there they reached , ; at PC Bruno, near Paris, they continued to work on the destruction of Enigma, collaborating with British cryptologists in Park when the British quickly got up to their job, breaking Enigma. Over time, British cryptographers, which included many chess masters and mathematicians such as , and (conceptual founder of modern computing), made significant breakthroughs in enigma scale and technology. The German code violation in World War II also had some success, most importantly, breaking the naval No 3. This allowed them to track and sink Atlantic convoys. Only -intelligence finally persuaded the Admiralty to change its codes in June 1943. This is surprising given the success of the British number 40 code breakers in the previous world war. At the end of the war, on April 19, 1945, Britain's top officers said they could never reveal that the German Enigma cipher was broken because it would give the defeated enemy a chance to say they were not well and fairly beaten. The German military also deployed several ciphers of the teleprinter. called them piphers of Pisces, and Max Newman and his colleagues developed and deployed Heath Robinson, then the world's first programmable digital electronic Colossus, to help with their cryptoanalysis. The German Ministry of Foreign Affairs began using the site at one time in 1919; some of this traffic was read during World War II partly as a result of the restoration of some key materials in South America that were discarded without sufficient care by the German courier. The Schlasselgeret 41 was developed at the end of the war as a safer replacement for Enigma, but was only used only limitedly. Japan's U.S. Army Group, SIS, managed to break the highest security of the Japanese diplomatic encryption system (an electromechanical step switch machine called Purple Americans) in 1940, before the outbreak of World War II. The On-site Purple vehicle replaced an earlier red vehicle used by the Japanese Ministry of Foreign Affairs and a related M-1 vehicle used by naval attaches that was broken by the U.S. Navy's Agnes Driscoll. All the Japanese ciphers of the machine were broken, to varying degrees, by the Allies. The Japanese navy and army mainly used code systems, later with a separate numerical supplement. Cryptographers of the U.S. Navy (in collaboration with British and Dutch cryptographers after 1940) hacked several crypto systems of the Japanese Navy. A breakthrough in one of them, the JN-25, famously led to the victory of the United States at the Battle of Midway; and to publish this fact in the Tribune shortly after the battle, although the Japanese didn't seem to notice because they continued to use the JN-25 system. Allies of the Americans referred to intelligence obtained as a result of cryptoanalysis, possibly especially from the Purple machine, like . The British eventually settled on 'Ultra' for exploration as a result of cryptoanalysis, in particular that traffic messages are protected by various Enigmas. An earlier British term for Ultra was Boniface in an attempt to suggest if betrayed that he might have an individual agent as a source. SIGABA is described in the U.S. patent 6,175,625 , filed in 1944, but not issued until 2001. Allied cipher machines used in World War II included the British and SIGABA; both were electromechanical rotor designs in spirit to Enigma, albeit with major improvements. None of them are known to have been broken by anyone during the war. The Poles used the machine, but its security was less than expected (by the cryptographers of the Polish army in Great Britain), and its use was discontinued. U.S. troops used the M-209 and even less secure M-94 family vehicles in the field. British SOE agents initially used poem ciphers (memorable verses were encryption/deciphering keys), but later, during the war, they began to switch to a one-off pad. The VIC cipher (used at least until 1957 in connection with Rudolf Abel's NY spy ring) was a very sophisticated hand cipher, and is said to be the most sophisticated being known to have been used by the Councils, according to David Kahn's Kahn on the codes. To decipher Soviet ciphers (especially when reusing single-folds), see the Venona project. The role of women The UK and US used a large number of women in their code-breaking operations, with nearly 7,000 reporting to Bletchley Park and 11,000 to separate US Army and Navy operations, around Washington, D.C. Traditionally in Japan and Nazi doctrine in Germany, women were suspended from military service, at least until the end of the war. Even after the encryption systems were broken, it was necessary to work hard to respond to the changes made, restore daily key stackings for multiple networks, and intercept, process, translate, prioritize, and analyze the huge volume of enemy messages generated during the global conflict. Several women, including Elizabeth Friedman and Agnes Meyer Driscoll, were heavily involved in violating the U.S. code in the , and the Navy and Army began actively recruiting top female college graduates shortly before the attack on Pearl Harbor. Lisa argues that this disparity in the use of women's talents between NATO allies and the Axis has made a strategic difference in the war. Modern encryption :p.29 nowadays is achieved by algorithms that have a key for encrypting and decrypting information. These keys convert messages and data into digital gibberish with encryption and then return them to their original form by decrypting them. In general, the longer the key, the harder it is to crack the code. This is true, because deciphering an encrypted message in brute force will require the attacker to try all possible keys. To put this into context, each binary unit of information, or , has a value of 0 or 1. The 8-bit key will have 256 or 2'8 possible keys. The 56-bit key will have 2'56, or 72 quadrillion, possible clues to try to decipher the message. Using state-of-the-art technology, ciphers using With such lengths, it is becoming easier to decipher. DES, an early U.S. government-approved cipher, has an effective key length of 56 , and test messages using this cipher were disrupted by the search for brute force keys. However, however, technology advances, so does the quality of encryption. Since World War II, one of the most notable advances in the study of cryptography has been the introduction of asymmetric key ciphers (sometimes referred to as open key ciphers). These are algorithms that use two mathematically connected keys to encrypt the same message. Some of these algorithms allow the publication of one of the keys, because of its extremely difficult to identify one key simply from the knowledge of another. Beginning around 1990, the use of the Internet for commercial purposes and the introduction of commercial transactions over the Internet have called for a broad standard of encryption. Prior to the introduction of Advanced Encryption Standard (AES), information sent over the Internet, such as financial data, was encrypted, if at all, by the Data Encryption Standard (DES). This has been approved by the NBS (US government agency) for its security, following a public appeal to, and competition between candidates for such a cipher algorithm. DES was approved for a short period of time, but saw expanded use due to complex disputes over the public's use of high-quality encryption. DES has finally been replaced by AES after another public competition organized by NBS's successor agency, NIST. Around the late 1990s and early 2000s, the use of common key algorithms became a more common approach to encryption, and soon a hybrid of the two schemes became the most common way to continue e-commerce operations. In addition, the creation of a new protocol, known as Secure Socket Layer, or SSL, has become the basis for online transactions. Transactions ranging from buying goods to online payment accounts and banking used SSL. In addition, as wireless Internet connections became more common among households, the need for encryption grew as security was required in such day-to-day situations. Claude Shannon Claude E. Shannon, considered by many, is the father of mathematical cryptography. Shannon worked for several years at Bell Labs, and during his time there, he produced an article entitled Mathematical Theory of Cryptography. This article was written in 1945 and was eventually published in the technical journal Bell System in 1949. It is generally believed that this article was the starting point for the development of modern cryptography. Shannon was inspired during the war to solve the problems of cryptography, because the secrecy systems provide an interesting application of communication theory. Shannon defined two main goals of cryptography: secrecy and authenticity. His focus was on exploring the mystery and thirty-five years later, G.J. Simmons would decide on the issue of authenticity. Shannon wrote another article entitled Mathematical communication, which highlights one of the most important aspects of the work: the transition of cryptography from art to science. In his work, Shannon described two main types of secrecy systems. First, those designed to protect against hackers and intruders who have endless resources with which to decipher the message (a theoretical secret, now unconditional security), and the second are those designed to protect against hackers and attacks with finite resources with which to decrypt the message (practical secret, now computing security). Much of Shannon's work focused on theoretical secrecy; here Shannon presented a definition of the inviolability of the cipher. If the cipher was defined as indestructible, it was considered an ideal mystery. Proving perfect secrecy, Shannon decided that this could only be obtained with a secret key, the length of which, presented in binary numbers, was larger or equal to the number of bits contained in encrypted information. In addition, Shannon has developed a distance of unity, defined as the amount of that ... determines the secret key. Shannon's work influenced further research into cryptography in the 1970s, as cryptography developers M. E. Hellman and W. Diffie called Shannon's research a major influence. His work has also influenced modern designs of secret ciphers. At the end of Shannon's cryptography work, progress slowed until Hellman and Diffie presented their work, which involved open key cryptography. The mid-1970s encryption standard saw two major public (i.e. unclassified) achievements. First, on March 17, 1975, a draft data encryption standard was published in the U.S. Federal Register. The proposed DES cipher was presented by a research team at IBM at the invitation of the National Standards Bureau (now NIST) to develop secure electronic communications for businesses such as banks and other large financial institutions. After consultations and modifications by the NSA operating behind the scenes, it was adopted and published as the Federal Information Processing Standard Publication in 1977 (now on FIPS 46- 3). DES was the first publicly available cipher that was blessed by a national agency such as the NSA. The release of its NBS specification spurred an explosion of public and academic interest in cryptography. The aging DES was officially replaced by Advanced Encryption Standard (AES) in 2001 when NIST announced FIPS 197. After an open competition, NIST chose Rijndael, represented by two Belgian cryptographers, for AES. DES, and safer versions of it (such as Triple DES), are still in use today, being incorporated into many national and organizational standards. However, its 56-bit key size was shown insufficient to defend against brute force attacks of such attacks by the cyber-rights group The Border Fund in 1997, succeeded in 56 hours. As a result, the use of direct DES encryption is now no doubt unsafe to use in the new crypto-system designs, and messages protected by older crypto systems using DES, and all messages sent since 1976 with DES are also under threat. Regardless of the quality of des' inherent, the size of the DES key (56-bits) was thought to be too small by some even in 1976, perhaps most publicly Whitfield Diffie. It was suspected that government agencies already had sufficient computing power to break DES messages; it is clear that others have reached that potential. The public key of the Second Development, in 1976, was perhaps even more important because it radically changed the way crypto-systems work. This was the publication of Whitfield Diffie and Martin Hellman's New Directions in Cryptography. It introduced a radically new method of distributing cryptographic keys that went far toward solving one of the fundamental problems of cryptography, key distribution, and became known as diffie-Hellman . The article also stimulated the almost immediate public development of a new class of encryption algorithms, asymmetrical key algorithms. Until that time, all the useful modern encryption algorithms were symmetrical key algorithms, in which the same cryptographic key was used with the basic algorithm of both the sender and the recipient, who should keep it secret. All the electromechanical machines used in World War II were of this logical class, like the ciphers of Caesar and Asbash and, in fact, all encrypted systems throughout history. The key for the code is, of course, , which should also be distributed and kept secret, and therefore shares most of the same problems in practice. If necessary, the key in each such system had to be exchanged between the parties communicating in some safe way before any use of the system (a term commonly used through a ) such as a reliable courier with a portfolio of handcuffs on his wrist, or face-to-face contact, or a loyal pigeon carrier. This requirement is never trivial and very quickly becomes unmanageable as the number of participants increases, or when secure channels are unavailable for key exchange, or when, as is reasonable cryptographic practice, keys often change. In particular, if messages are designed to protect against other users, each possible pair of users requires a separate key. This kind of system is known as a secret key, or a symmetrical key of the crypto system. Sharing D-H keys (and subsequent improvements and options) have made these systems work a lot easier and safer than ever In all of history. In contrast, asymmetrical key encryption uses a pair of mathematically connected keys, each of which deciphers encryption made with the other. Another. but not all of these algorithms have the added property that one of the paired keys cannot be derived from the other by any known method other than trial and error. This kind of algorithm is known as a public key or asymmetric key system. Using this algorithm, only one key pair is required per user. Visiting one key pair as a private (always secret) and the other as a public (often widely available), the key exchange does not require a secure channel. As long as the private key remains secret, the open key can be widely known for a very long time without compromising security, making it safe to reuse the same pair of keys indefinitely. For two users of an asymmetrical key algorithm to securely communicate through an unsafe channel, each user will need to know their own public and private keys, as well as another user's public key. Take this basic scenario: Alice and Bob each have a couple of keys they've used over the years with many other users. At the beginning of their message, they exchange public keys that are unencrypted along an unsafe line. Alice then encrypts the message with her personal key, and then re-encrypts the message using Bob's public key. A double encrypted message is sent in the form of digital data over the wire from Alice to Bob. Bob gets a bit of a stream and deciphers it using his personal key and then deciphers that bit of flow using Alice's public key. If the end result is recognizable as a message, Bob can be sure that the message actually came from someone who knows Alice's personal key (presumably actually her if she was careful with her personal key), and that any eavesdropping on the channel would need Bob's personal key to understand the message. Asymmetrical algorithms rely on their effectiveness on class problems in mathematics, called one-way functions that require relatively little computing power to perform, but a huge amount of energy to reverse if a reversal is possible at all. A classic example of a function with one method is multiplying a very large, simple number. It's pretty quick to multiply the two big primes, but it's very hard to find the product factors of two big primes. Because of the math of functions with one way, the most possible clues are poor choices as cryptographic keys; Only a small fraction of possible keys of a certain length are suitable, so asymmetrical algorithms require very long keys to achieve the same level of security as relatively short symmetrical keys. The need to both generate key pairs and perform encryption/decryption operations makes asymmetrical algorithms expensive, compared to most symmetrical algorithms. Because symmetrical algorithms can often use any sequence of (random or at least unpredictable) bits as a key, a one-time session key can be quickly generated for short-term use. Therefore, it is common practice to use the use of asymmetric key for exchanging disposable, much shorter (but equally strong) symmetrical key. The slower asymmetrical algorithm reliably sends a symmetrical session key, and the faster the symmetrical algorithm takes over the rest of the message. Asymmetrical cryptography of keys, Diffie-Hellman's key exchange and the most well-known of public key/private key algorithms (i.e. what is commonly referred to as the RSA algorithm) all seem to have been independently developed by the British intelligence agency prior to the public announcement of Diffie and Hellman in 1976. The SCCP published documents alleging that they developed open-key cryptography prior to the publication of Diffie and Hellman's work. Various classified documents were written in the SCCP in the 1960s and 1970s, which eventually led to schemes essentially identical to RSA encryption and the exchange of Diffie-Hellman keys in 1973 and 1974. Some have already been published, and inventors (James H. Ellis, Clifford Cox and Malcolm Williamson) have published (some of) their work. Hashing is a common method used in cryptography to quickly encode information using typical algorithms. Typically, the algorithm is applied to the text line, and the resulting line becomes the hash value. This creates a digital fingerprint of the message, as the specific hash value is used to identify a particular message. Exiting the algorithm is also called a message digest or check-sum. Hashing is good for determining whether the information in the transmission has been altered. If the hash value is different when you receive it than when you send it, there is evidence that the message has been changed. Once the algorithm has been applied to the data for hashing, the hash function produces a fixed length output. In fact, anything that passes through the hash function should be allowed at the same length output as anything else passed through the same hash function. It is important to note that hashing is not the same as encryption. Hashing is a one-way operation used to convert data into a compressed digest message. In addition, the integrity of the message can be measured by hashing. Conversely, encryption is a two-dimensional operation that is used to convert plain text into cipher, and then vice versa. Encryption guarantees the confidentiality of the message. Hash functions can be used to verify digital signatures, so that when signing documents over the Internet, the signature applies to one particular person. Like a handwritten signature, these signatures are verified by assigning an exact hash code to a person. In addition, hashing is applied to passwords for computer systems. Password hashing began with the UNIX operating system. The user in the system will first create This password will be hashed using an algorithm or key and then saved password file. This is still evident today, as web applications that require passwords often hash out user passwords and store them in a database. The cryptography of the politics of the Public Events of the 1970s broke almost a monopoly on high quality cryptography conducted by government organizations (see S Levi Crypto for the journalistic account of some of the political disputes of the time in the US). For the first time, these external governmental organizations gained access to cryptography that was not easily broken by anyone (including governments). Significant disputes and conflicts, both public and private, began more or less immediately, sometimes called crypto wars. They haven't subsided yet. In many countries, for example, the export of cryptography is subject to restrictions. Until 1996, exports from U.S. cryptography using keys longer than 40 bits (too small to be very safe against a know-it-all intruder) were severely restricted. As recently as 2004, former FBI Director Louis Gray, testifying before the 9/11 Commission, called for new laws against the public use of encryption. One of the most significant people who prefer strong encryption for public use was Phil zimmermann. He wrote and then in 1991 released PGP (Pretty Good Privacy), a very high quality crypto system. He distributed a free version of PGP when he felt threatened by the legislation, something under consideration by the U.S. government that would require backdoors to be included in all cryptographic products developed in the U.S. His system was released worldwide shortly after he released it in the U.S., and it launched a lengthy criminal investigation against him by the U.S. Department of Justice for alleged violation of export restrictions. The Department of Justice eventually dropped its case against zimmermann, and the distribution of free PGP software continues around the world. PGP even eventually became the open standard of the Internet (RFC 2440 or OpenPGP). Modern cryptoanalysis While modern ciphers such as AES and better asymmetric ciphers are widely considered indestructible, bad projects and implementations are still sometimes accepted and have been important crypto-analytical interruptions of deployed crypto systems in recent years. Notable examples of broken crypto structures include the first Wi-Fi WEP encryption scheme, the scrambling content scrambling system used to encrypt and control the use of DVDs, the A5/1 and A5/2 ciphers used in GSM cell phones, and the CRYPTO1 cipher used in NXP Semiconductors' widely deployed MIFARE Classic smart cards. All of them are symmetrical ciphers. So far, none of the mathematical ideas underlying cryptography keys have not been proven as indestructible and so some future pre-mathematical analysis can make the systems based on them unsafe. While few informed observers foresee such a thing, the key size recommended for security, as the best practice is to increase the computing power needed to break the codes, it becomes cheaper and more accessible. The quantum , if ever built with sufficient power, can break existing public key algorithms and efforts are being made to develop and standardize post-. Even without breaking encryption in the traditional sense, side attacks can be installed that use information derived from the way a computer system is used, such as the use of cache memory, time information, energy consumption, electromagnetic leaks or even sounds emitted. New cryptographic algorithms are being developed to overshadow such attacks. See also the NSA Steganography Encryption System Timeline of Cryptography Topics in The Cryptography of Japanese Cryptology from the 1500s to the Meiji World War I Cryptography List of Cryptographers Category: Inaudible Historical Codes and Cipher Links - b d A Brief . Syfer Research Laboratories. January 24, 2006. Received on September 18, 2013. Cryptography in ancient civilizations. Received on September 18, 2013. Kahn, David. Codebreakers: A comprehensive history of secret links from ancient times on the Internet, revised and updated. Scribner. New York, New York. A brief history of cryptography. Cryptosine. May 16, 2008. b c 2.1 - A short history of cryptography. all.net. received on March 19, 2018. Translators: Richard Burton, Bhagavanlal Indrajit, Shivaram Parashur Bhaide (January 18, 2009). Kama Sutra of Vacayana (translated from Sanscrit in seven parts with a foreword, introduction and closing remarks). The Gutenberg Project. 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Po: A sad and endless memory. New York: Harper Perennial, 1991. page 152-3 - Infographic - the history of encryption. www.egress.com received on March 19, 2018. Fenton, Ben (June 22, 2006). Enigma and the British Code of Honour. The Daily Telegraph. London. Fessenden, Marissa (January 27, 2015). In Bletchley Park, women were the key to breaking the World War II code. Smithsonian magazine. Received on May 10, 2019. At its peak, Bletchley Park employed more than 10,000 people, more than two-thirds of whom were women. a b, Lisa (2017). Code Girls: The Untold Story of American Women Violators of the World War II Code. New York, Boston: Hachette Books. ISBN 978-0-316-35253-6. Frumkin, Dan (May 8, 1998). Deciphering encryption. Washington Post. received on September 18, 2013. Tom Lee (August 2000). Cryptography and the New Economy (PDF). Industrial physicist. 6 (4): 31. Archive from the original (pdf) dated February 16, 2012. 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