Editing Encryption (section)

== History ==

=== 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.<ref name=":4">{{Cite web|url=https://www.binance.vision/security/history-of-cryptography|title=History of Cryptography|website=Binance Academy|language=en|access-date=2020-04-02|archive-date=2020-04-26|archive-url=https://web.archive.org/web/20200426075650/https://www.binance.vision/security/history-of-cryptography|url-status=dead}}</ref>  One of the most famous military encryption developments was the [[Caesar cipher]], in which a plaintext letter is shifted a fixed number of positions along the alphabet to get the encoded letter. A message encoded with this type of encryption could be decoded with a fixed number on the Caesar cipher.'''<ref>{{Cite web|url=https://www.geeksforgeeks.org/caesar-cipher-in-cryptography/|title=Caesar Cipher in Cryptography|date=2016-06-02|website=GeeksforGeeks|language=en-US|access-date=2020-04-02}}</ref>'''

Around 800 AD, Arab mathematician [[Al-Kindi]] developed the technique of [[frequency analysis]] – which was an attempt to crack ciphers systematically, including the Caesar cipher.<ref name=":4" /> This technique looked at the frequency of letters in the encrypted message to determine the appropriate shift: for example, the most common letter in English text is E and is therefore likely to be represented by the letter that appears most commonly in the ciphertext. This technique was rendered ineffective by the [[polyalphabetic cipher]], described by [[Al-Qalqashandi]] (1355–1418)<ref name=":5">{{cite book |last1=Lennon |first1=Brian |url=https://books.google.com/books?id=jbpTDwAAQBAJ&pg=PT26 |title=Passwords: Philology, Security, Authentication |date=2018 |publisher=[[Harvard University Press]] |isbn=9780674985377 |page=26}}</ref> and [[Leon Battista Alberti]] (in 1465), which varied the substitution alphabet as encryption proceeded in order to confound such analysis.

=== 19th–20th century ===
Around 1790, [[Thomas Jefferson]] theorized a cipher to encode and decode messages to provide a more secure way of military correspondence. The cipher, known today as the Wheel Cipher or the [[Jefferson disk|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.'''<ref>{{Cite web|url=https://www.monticello.org/site/research-and-collections/wheel-cipher|title=Wheel Cipher|website=www.monticello.org|language=en|access-date=2020-04-02}}</ref>'''

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.<ref>{{Cite web|url=https://www.cryptomuseum.com/crypto/usa/m94/index.htm|title=M-94|website=www.cryptomuseum.com|access-date=2020-04-02}}</ref>

In World War II, the Axis powers used a more advanced version of the M-94 called the [[Enigma machine|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.<ref>{{cite news |last1=Hern |first1=Alex |title=How did the Enigma machine work? |url=https://www.theguardian.com/technology/2014/nov/14/how-did-enigma-machine-work-imitation-game |work=The Guardian |date=14 November 2014 }}</ref> 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.<ref name=":1" /> As computing power continues to increase, computer encryption is constantly evolving to prevent [[eavesdropping]] attacks.<ref>{{cite magazine |last1=Newton |first1=Glen E. |title=The Evolution of Encryption |url=https://www.wired.com/insights/2013/05/the-evolution-of-encryption/ |magazine=Wired |others=Unisys |date=7 May 2013 }}</ref> One of the first "modern" cipher suites, [[Data Encryption Standard|DES]], used a 56-bit key with 72,057,594,037,927,936 possibilities; it was cracked in 1999 by [[Electronic Frontier Foundation|EFF's]] brute-force [[EFF DES cracker|DES cracker]], which required 22 hours and 15 minutes to do so. Modern encryption standards often use stronger key sizes, such as [[Advanced Encryption Standard|AES]] (256-bit mode), [[Twofish|TwoFish]], [[ChaCha20-Poly1305]], [[Serpent (cipher)|Serpent]] (configurable up to 512-bit). Cipher suites that use a 128-bit or higher key, like AES, will not be able to be brute-forced because the total amount of keys is 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 [[Backdoor (computing)|backdoors]] or by exploiting physical side effects through [[Side-channel attack]]s. For example, [[RC4]], a stream cipher, was cracked due to inherent biases and vulnerabilities in the cipher.