Bellaso's Reciprocal Ciphers
2006; Taylor & Francis; Volume: 30; Issue: 1 Linguagem: Inglês
10.1080/01611190500383581
ISSN1558-1586
Autores Tópico(s)Cryptographic Implementations and Security
ResumoAbstract A tableau with reciprocal alphabets used with a long keyword is commonly attributed to Della Porta. This cipher had actually been published a decade before by Giovan Battista Bellaso in a rare booklet containing other original ciphers. Keywords: BellasoDella PortaautokeyVigenèrecountersignspolyalphabetic substitutionreciprocal alphabets Notes 1Giovan Battista DELLA PORTA (1535–1615). Neapolitan polymath, son of Leonardo Della Porta, researcher and divulger of scientific curiosa, founder of the Accademia dei Segreti, which was prohibited by Pope Paul V in 1578. Author of De furtivis literarum notis, 1563, which enjoyed great success and was reprinted many times with additions by other hands [Citation5]. 2Antonio ELIO (1506–1576) from Capodistria, secretary to Paul III and Paul IV, bishop of Pola and Vicar of St. Peter (1559), founder of the cipher office. Nicknamed Antonio delle cifre Vincenzo MAGGI, Brescian philosopher, scholar, taught in Padua and Ferrara, where he died in 1564. Nicolò SECCO from Montichiari, lawyer, dramatist, mathematician, captain of justice in Milan (1553), died in Rome in 1560. 3Paolo AVOGADRO, of Brescian family coming from Val Trompia, involved in the commotions of 1512. Gianfrancesco GAMBARA (1533–1587), of a noble Brescian family, domestic secretary to Julius III, cardinal, legate to Camerino. Girolamo RUSCELLI, grammarian, writer, died in Venice in 1566. 4Rodolfo PIO (1500–1564), a gentleman of Carpi, bishop, cardinal. He held multiple important offices during the pontificates of Paul III, Julius III, Pius IV and enjoyed the favor of the king of Spain. 5Durante DURANTI (Palazzolo 1487 or 1492—Brescia 1558) former secretary to Paul III and bishop of Alghero, cardinal in 1544, governor of Narni and Camerino from 1549, bishop of Brescia from 1551. He was a fierce enemy of Benvenuto Cellini. Table of ten keyword-mixed alphabets from: Il vero modo di scrivere in cifra… Bressa 1564 [Citation3]. Table of five keyword-mixed alphabets from: Il vero modo di scrivere in cifra… Bressa 1564 [Citation3]. 6Alessandro FARNESE (1520-1589) of the dukes of Parma, Paul III's nephew, bishop, cardinal. He was a guest of Cosimo de' Medici for ten months in 1551. 7A translation is given here. Please note that the numbers of the cipher methods are not always congruent. The first quality of these ciphers is that even if somebody's encrypting methods (formed according to my guidelines) were universally known, one would read his messages no better than a blank sheet. The second quality is that considering their security, the ciphers are so rapid in ciphering and deciphering, that no other cipher can be found to equal them after some training. The third quality is that with the first, third, fourth and fifth methods one can work without a worksheet, which means that although a beginner may encounter some difficulty, the well trained person will find it easy and amusing. The fourth quality of these ciphers is that they only use letters of the alphabet without nulls, paragraphs, dots, dashes, or doubled letters. The fifth quality is that if the first four tables are lost by accident, they can be immediately reconstructed as they were before by use of the keywords that originated the alphabet. The sixth quality is that the ciphers are changed by altering the keyword by which the alphabets are compiled. Thus the cipher itself is changed because we change the substance and not the outward appearance. The seventh quality is that as many ciphers can be formed, as any verses exist in the world, in any language, or by using strange words like giracol or other such expressions. One can also use superenciphered keywords to generate new tables frequently and without danger. The eighth quality is that, in view of what was said above, a Prince having many Ambassadors with different gentlemen may generate a different cipher for each Ambassador and often change it at will without involving his secretary for enciphering and deciphering many different ciphers for different Ambassadors. This is very important because if the ciphers were all alike, an unfaithful secretary might give a copy of the cipher to an enemy, allowing him to read all the messages sent to all other Ambassadors when intercepted. The ninth quality is that if a Prince had an untaught or unreliable secretary involved in the interpretation of some important detail, he may take the table in his hands and encipher or decipher those particular passages at will without excessive trouble. The tenth quality is that with the fifth and sixth ciphers you write with fewer characters than in the original text. Using the letters of the alphabet, we accomplish what modern cipher clerks normally do with a bunch of different characters or numbers, or employing separate lists to indicate different words. The eleventh quality is that only one keyword is sufficient to write in cipher. The twelfth quality is that in the future, the Princes will not need professional cipher clerks because any faithful literate servant will be able to perform this function once he is familiar with these ciphers. The thirteenth quality is that especially with the third cipher, one can encipher one or two lines or different words here and there without enciphering the entire message. 8Car le livre cy devant allegué de Baptiste Porta, auquel il a inseré ce chiffre sans faire mention dont il le tenoit, ne sortit en lumiere que l'an 1563 [[Citation8], f. 36]. 9De mon invention puis-je dire, amené l'artifice de faire dependre toutes les lettres l'une de l'autre, ainsi que par enchaisnement, ou liaison de maçonnerie [[Citation8], f. 36v]. 10La ragione perche lassando cadere da alto à basso due palle, una di ferro, & l'altra di legno, così presto cada in terra quella di legno, como quella di ferro [Citation3].
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