Xi (letter) dialects of most of the Greek mainland and Euboea, the sound [ks] was represented by Χ (which in classical Greek is chi, used for ). Because this variant of the Greek alphabet was used in Italy, the Latin alphabet borrowed Χ rather than Ξ as the Latin letter X. While having no Latin derivative, the Xi was adopted into the early Cyrillic alphabet, as the letter ksi (Ѯ, ѯ). The uppercase letter Ξ is used as symbol for: The lowercase letter ξ is used as a symbol for: These characters are used only as mathematical symbols. Stylized Greek text should
The Alphabet Cipher The Alphabet Cipher Lewis Carroll published "The Alphabet-Cipher" in 1868, possibly in a children's magazine. It describes what is known as a Vigenère cipher, a well-known scheme in cryptography. While Carroll calls this cipher "unbreakable", Kasiski had published a volume describing how to break such ciphers from five years earlier, and Charles Babbage had secretly found ways to break polyalphabetic ciphers during the Crimean War. The piece begins with a tabula recta. ABCDEFGHIJKLMNOPQRSTUVWXYZ Each column of this table forms a dictionary of symbols representing the alphabet: thus, in the A column, the symbol is the same as the letter represented;