History of the Greek alphabet consonant letter, rather than seemingly have two exceptions in spelling. Greek, like Phoenician, made a distinction for vowel length; indeed, Greek had five short vowels and seven long vowels, but only five vowel letters. As in Phoenician, the difference in length was not originally made in writing. However, by the 6th century BC the letter eta (not needed for a consonant in eastern dialects of Greek, which lacked ) came to stand for the long vowel , and a new letter, omega, was developed for long . The provenance of omega is not known, but it is generally assumed to
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;