Spying has gotten a lot more sophisticated since John Paul was elected in 1978, but the Vatican seems confident it can protect the centuries-old tradition of secrecy that surrounds the gathering.
Vatican security refused to discuss the details of any anti-bugging measures to be used during the conclave. But Giuseppe Mazzullo, a private detective and retired Rome policeman whose former unit worked closely with the Vatican in the past, said the Holy See will reinforce its own experts with Italian police and private security contractors.
"The security is very strict," Mazzullo said. "For people to steal information, it's very, very difficult if not impossible."
Thousands of reporters will be watching as the 115 cardinals gather on April 18. Hackers and government informants may also be monitoring the conclave.
The temptations to spy will be immense. The papal election will likely see keen competition, notably between reformers and conservatives. It is also expected to witness a strong push for the first non-European pope.
Revelations of the proceedings could prove embarrassing to the Vatican. For instance, sensitive discussions on a papal candidate's stand on relations with Muslims or Jews, recognizing China rather than Taiwan, or views on contraception would be sought-after by governments or the press.
John Paul was sensitive to meddling from outside. He spent his formative years in Soviet-run Poland under pervasive government spying. The Turkish gunman who shot him in 1981 was suspected of ties to the Soviets, a regime later brought down by forces the pope openly supported.
The Vatican released video Monday of the closed world the cardinals will occupy until they choose a new pope, showing images of their hotel, the Sistine Chapel, the urns where they will place their votes and the stove that will send up smoke to signal that they have elected a new pontiff.
It also shows images of the round, bronze-rimmed urns where the cardinals will place their votes. Previously, cardinals placed their ballots in a chalice. The video ends with a view of the stove, dusty and full of ashes, where the ballots will be burned. Black smoke wafting from the Sistine Chapel's chimney signals no pope has been elected, and white smoke signals a new pope has been chosen.
Responding to John Paul's request, the Vatican will depart from centuries-old tradition by also ringing bells to signal the election in an effort to avoid confusion over the color of the smoke.
In 1996, John Paul set down rules to protect cardinals from "threats to their independence of judgment." Cell phones, electronic organizers, radios, newspapers, TVs and recorders were banned.
The ban on cell phones and personal data organizers makes sense, security experts say, since they can be hacked and used to broadcast the proceedings to a listener.
"An eavesdropper can reach into those devices and turn on the microphone and turn it into an eavesdropping device," said James Atkinson, who heads a Gloucester, Mass., company that specializes in bug detection. "It's extraordinarily easy to do."