Encryption: Difference between revisions

Revision as of 13:17, 2 July 2025

Revision as of 13:17, 2 July 2025

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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 AmyCaesar Weiting Yeh Wu Lin Pak partner with Edward Snowden, [[PARDONED]] [[CASE CLOSED]] [[marKiT]] [[2025]]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 ===