BLAISE DE VIGENERE Blaise de Vigenere was on a diplomatic mission in Rome when he first acted on his interests in cryptography. At the age of thirty-nine Vigenere began his life study of cryptography. With the detailed ideas of famous cryptographers, Alberti, Trithemius, and Porta, Vigenere developed a coherent and powerful new cipher. Vigenere's table consists of 26 horizontal alphabets; each slid one space to the left from the one above. This is the cipher alphabet. The alphabet at the top is for the plaintext, and another normal alphabet runs down the left side, which is the key alphabet. In Vigenere's system, the plain text is written down with the secret key words written above it. Each letter has to match with another letter, and the key words must be repeated as many times as needed. The enciphering begins with the pairing of letters. The cryptographer follows the alphabet at the top of the table until he reaches the first letter of the plain text; then he drops down this column until he finds the line, which begins with the first letter of the key word. At this junction, he will find the first letter of the cipher. This process is repeated until all of the plain text is converted into cipher. For many years Vigenere's system was called "the indecipherable cipher". This is because, unlike substitution, the same letter in the cipher did not substitute the same letter. Many different letters, therefore making it very hard to break, might encrypt the same letter.
