The secret to bringing down a notorious Mexican cartel kingpin? His IT guy.

Jurors in the trial of Joaquin “El Chapo” Guzman on Tuesday listened to damning phone calls of the diminutive drug lord running his cocaine empire — because the FBI successfully flipped his Sinaloa Cartel’s tech guru.

Prosecutors say they caught the elusive El Chapo on tape between 100 and 200 times, and wiretapped some 800 calls after the cartel’s in-house geek Cristian Rodriguez helped them decode its encrypted computer system.

The courtroom listened to around a dozen of the calls, hearing Guzman orchestrate a cocaine sale, speak to corrupt cops and try to calm an overzealous hitman.

The FBI first lured Rodriguez to a hotel room in Manhattan in 2010, where an undercover agent posed as a shady con looking to build his own encryption system, agent Stephen Marston told the court.

The agency then convinced Rodriguez to “proactively cooperate” with the government — continuing to work for the cartel while undercover.

The cartel’s servers were originally in Canada, but Rodriguez convinced his bosses to move them to the Netherlands — handing the feds the encryption keys in the process.

Marston has been able to ID Chapo’s voice on the calls through recordings of conversations he’s had while locked up in Manhattan’s Metropolitan Correctional Center as well as an interview the drug lord did with actor Sean Penn for Rolling Stone magazine.

“His voice has a higher pitch,” Marston said of Chapo. “It has kind of a singsongy nature to it. And you pick up kind of a nasally undertone.”

In multiple calls played to the court, a man identified as Chapo could be heard lambasting standover man Orso Ivan Gastelum Cruz — better known as “Cholo Ivan” — for beating up cops.

“Talk to them, you know they are policemen. It’s better not to smack them around,” he says in one.

“Why don’t they ask for permission, the bastards,” Cruz whines, then later boasts: “I kicked their asses.”

Chapo again warns him to “take it easy with the police.”

“Well you taught us to be a wolf,” Cruz responds. “I’m remembering, that’s how I like to do it.”