Vatican City has some wonderfully anachronistic characteristics — the official language is Latin, the elite guards wear colorful Renaissance-inspired uniforms and carry big spear-like halberds, it's essentially an absolute monarchy — but security for the secret election of the next pope is extremely modern.

That's not to say that we won't ever find out who almost became pope: After the last conclave, notes from an anonymous cardinal were leaked (an Argentine Jesuit cardinal was reportedly the runner-up to Pope Benedict), and last week self-styled German "bishop" Ralph Napierski got past Vatican security and mingled with actual cardinals before his ersatz cardinal cassock (and fedora) gave him away. But once the 115 cardinal electors cloister themselves in the Sistine Chapel and their Vatican hotel rooms, the Holy See will do just about everything in its earthly power to make sure what happens in the conclave stays in the conclave.

The 115 eligible cardinals will enter the Sistine Chapel at 4:30 pm (Rome), or 11:30 am in New York, on Tuesday. Then, with the Latin words "Extra omnes" — "Everyone out" — the conclave begins. The word conclave — "with key" — refers to a locked room, and the tradition of putting the cardinals behind lock and key dates back to 1274, during the longest conclave ever (two years and eight months). As the story goes, the villagers of Viterbo grew so frustrated by the prolonged deliberations in their town that they locked the cardinals in a building, tried to starve them, and even tore the roof off to deprive the prelates of shelter.

"Closed doors are no longer enough in the 21st century," of course, says Reuters' Naomi O'Leary, and neither, it seems, is the solemn oath each cardinal takes, hand on Gospels and at threat of excommunication, "to observe, both with clerics and laymen, the secrecy of all that regards the election of the Roman pontiff and what takes place in the place of election."

So Vatican police have installed electronic jamming devices under the elevated floor in the Sistine Chapel, and they will sweep the room and the cardinals' living quarters for electronic eavesdropping bugs. All electronic recording devices, both audio and video, are forbidden, as is all contact with the outside world, barring "extremely grave and urgent reasons," and only then with special permission. No TV, no Twitter, no radio, no newspapers. The cardinals will be escorted to their rooms, a few hundred yards away by foot (or special bus) in the Domus Sanctae Marthae (Casa Santa Marta), a guesthouse run by nuns. The nuns, doctors, technicians, and anyone else who will aid the cardinals will be run through a metal detector and also face excommunication for blabbing.

The daunting job of keeping the conclave leak-proof is on the shoulders of the Vatican chamberlain, Cardinal Tarcisio Bertone, three cardinal assistants, and two technicians. Well, that and the solemn oaths of the gathered princes of the church. "We are counting on people's morality and responsibility," says Vatican spokesman Fr. Federico Lombardi. The cardinals can draw inspiration from Michelangelo's famous fresco above them, says The Associated Press' Frances D'Emilio. But "if they need a reminder about the oath of secrecy, on the wall behind the chapel's altar is the artist's 'Last Judgment' — with its frightening depictions of the damned."

Here's a video primer on the conclave, from Catholic News Service:

Sources: ABC News, The Associated Press, Reuters, USCCB