The recently arrested "boss of bosses" of the Sicilian Mafia, Bernardo Provenzano, wrote notes using an encryption scheme similar to the one used by Julius Caesar more than 2,000 years ago, according to a biography of Italy's most wanted man.

The biography, written by journalists Salvo Palazzolo and Ernesto Oliva, is published in Italian on www.bernardoprovenzano.net, which is the most exhaustive Web site on Provenzano.

Accused of numerous murders, including the 1992 killings of two judges for which he was sentenced to life in jail, the 73-year-old boss was arrested last week in a farmhouse about just a few miles from his Sicilian hometown Corleone, a place forever associated with the Godfather saga.

Also known as "Binnu u tratturi" (Binnu the tractor) because of his reputation for mowing down people in his youth, Provenzano had been on the run for more than 40 years, many of them spent writing cryptograms on little pieces of paper, known in Sicilian dialect as pizzini.

The Italian police found about 350 pizzini in Provenzano's hideaway.

A few dozen of these notes contained requests to his family, such as having lasagne on Easter. All the others, featuring orders to his lieutenants, displayed numeric sequences that concealed the names of people.

Caesar Cipher
At least one coded note, published in the Web site's biography, has a strong resemblance to what's known as Caesar cipher, an encryption scheme used by Julius Caesar to protect important military messages.

The letter, written in January 2001 by Angelo Provenzano to his father, was found with other documents when one of Provenzano's men, Nicola La Barbera, was arrested

"...I met 512151522 191212154 and we agreed that we will see each other after the holidays...," said the letter, which included several other cryptograms.

"The Binnu code is nothing new: each number corresponds to a letter of the alphabet. "A" is 4, "B" is 5, "C" is 6 and so on until the letter Z , which corresponds to number 24," wrote Palazzolo and Oliva.

While the classic Caesar cipher moves everything three letters later (A becomes D, B becomes E, etc.), the "Provenzano code" assigns a number to each letter by simply increasing by 3 the value given to the 21 letters of the Italian alphabet listed in order.

So, A becomes 4 (1+3), B becomes 5 (2+3), C becomes 6 (3+3), etc

"In the Provenzano code the key is the +3 shift," mathematics expert Alessandro Martignago told Discovery News.

As the code is cracked, the "512151522 191212154" person becomes "Binnu Riina." Most likely, it refers to Bernardo Riina, arrested on Wednesday on suspicion of aiding Provenzano while he was on the run.

According to Martignago, the Provenzano code might have been made more secure by changing the + 3 key with other shift characters ( +5, +7, +8, etc.) from time to time.

"Looks like kindergarten cryptography to me. It will keep your kid sister out, but it won't keep the police out. But what do you expect from someone who is computer illiterate?" security guru Bruce Schneier, author of several books on cryptography, told Discovery News.

Indeed, no high-tech ran the Mafia network under Provenzano's rule. Top Mafia businesses were conducted on an obsolete Olivetti Lettera 32 typewriter. Pizzini were delivered by a chain of messengers.

The fact that the boss code was rather straightforward may be explained by Provenzano's lack of education. It stopped when he dropped out of school at about eight.

Anna Petrozzi is an editor at Antimafia 2000, a magazine that Provenzano read, as copies found in his hideaway attest.

"The police are not new to these coded messages. When they arrested in 2002 Antonio Giuffré, one of his right-hand men then turned informer, and about 30 pizzini came to light," she told Discovery News.

Those pizzini helped investigators enormously. Once the cryptograms were decoded, several members of Provenzano's close circle were identified, a step which ultimately led to his arrest.

"Now we will have to work on the newly discovered pizzini, which contain several coded names. We have known the system used to code them since 2002," assistant state prosecutor Giuseppe Pignatone told state television RAI 2 on Thursday.