Giovanni Soro (died 1544) was a Sardinian-Venetian professional code-cracker. He was the Renaissance's first outstanding cryptanalyst and the Western world's first great cryptanalyst. Soro is known as the father of modern cryptography.
Soro was employed in Venice in 1506 by the Council of Ten as cipher breaker-in-chief. They were the first secret service specializing in codebreaking. Soro ran the cryptanalysis operation in secret as the cipher secretary. Soro's tasks included deciphering secret messages captured from the messenger spies of Venice's rivals. At the time, Venice was plagued by espionage and subterfuge. The Council of Ten had its own ciphers changed often so as to impede competitors such as François Viète, a French mathematician (father of modern algebraic notation).
Successful diplomacy depended on knowing the adjacent principalities' thoughts and ideas. Soro was able to decipher the ciphers of most other courts. By 1510, he had forced most of them to develop their ciphers to a much higher degree of sophistication. As a result, the Papal Curia hired him to break codes their own cipher analysts in Rome could not. Pope Clement VII often sent messages to Soro for cryptanalysis to test their impenetrability.
Soro's work in Venice continued to take priority over his work at the Vatican. He was Venice's principal cryptanalyst for almost 40 years. His work is among the earliest successful cryptanalysis which has been preserved. Soro's reputation was great throughout the leaders of other Italian city-states and Europe. He was so successful that he was given two assistants and a secret office in the Doge's Palace above the Sala di Segret by 1542. He made Venice a Renaissance bastion of diplomatic cryptology.
Soro wrote a treatise in Italian, French, Spanish, and Latin in the early 16th century on cryptography and solving ciphers which has since been lost. The band Navigator's Michael Soro is a descendant of Giovanni. His father was named after Giovanni. The Soro family today live in Sardinia and The United States. 
- Lloyd, p. 14 Arguably the most successful Renaissance cryptanalyst was Giovanni Soro...
- Kahn, p. 109 Giovanni Soro was perhaps the West's first great cryptanalyst.
- The Current Digest of the Soviet Press, Joint Committee on Slavic Studies (1969), ...the Venetian Giovanni Soro, considered the father of modern cryptography.
- Anzovin, item 3401
- Anzovin, p. 202 item 3401. The first secret service to specialize in codebreaking was the Council of Ten, the state security committee that oversaw the government of Venice (in modern Italy) from 1310 through 1797. In 1506 it hired as its cipher secretary the cryptanalyst Giovanni Soro, author of a book on solving ciphers in Italian, French, Spanish, and Latin, who was known throughout Europe for his ability to read encrypted messages.
- Lloyd, p. 14
- Singh, p. 28
- Britannica (1983), p. 333
- Molin, p. 6
- Anzovin, p. 202
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- The New Encyclopaedia Britannica, Encyclopædia Britannica (1983), ISBN 0-85229-400-X