By Eric Levenson

CNN

(CNN) -- An extortion case involving bikini-clad models, social media celebrities and racy images has sparked an intriguing legal debate over phone security and the Fifth Amendment.

The big question: Can authorities access potentially incriminating information on your phone by compelling you to reveal your passcode? Or is verbal access to your phone's secrets protected under the Constitution?

The case stems from the arrest of Hencha Voigt, 29, and her then-boyfriend, Wesley Victor, 34, last July on charges of extortion. Voigt and Victor threatened to release sexually explicit videos and photos of social media star "YesJulz" unless she paid them off, according to a Miami Police Department report.

Both Voigt and "YesJulz" are big names on social media. Voigt is a fitness model and Instagram celebrity who starred last fall on "WAGS Miami," an E! reality TV show about the wives and girlfriends of sports figures in South Beach.

YesJulz, 27, whose real name is Julieanna Goddard, is a party promoting jet-setter who was described as "Snapchat Royalty" in a profile last year in The New York Times magazine.

As part of the ongoing investigation into the case, prosecutors have sought to search Voigt's and Victor's phones and asked a judge to order the two to give up their phone passcodes.

Attorneys for the two suspects have pushed back, arguing that passcodes are equivalent to self-incriminating testimony that is protected under the Fifth Amendment.

"They're asking for the passcode so they can keep on searching what's on the phone -- which may be incriminating my client -- and then use that against her," Kertch Conze, Voigt's attorney, told CNN.

A ruling on this question is expected on Wednesday. But no matter its result, the broader question of passcode security and the Fifth Amendment has become a "hot issue" at the center of many criminal trials, according to Joshua J. Horowitz, an attorney specializing in technology-related litigation.

"This is definitely a question that is percolating in the lower courts and will eventually make its way up to the Supreme Court," Horowitz said. "Until it does, there's really no clear answer on this issue."

The arrests

In text messages last July, Voigt and Victor allegedly told Goddard to pay $18,000 in cash within 24 hours or they would release the sexually explicit videos and photos, according to a police report.

"(You) can have them back as I said you dope chick," Victor said in a text message, according to the police report. "I like your movement look if I feel any fun business game over your choice."

Voigt and Victor were arrested that same day while sitting in a vehicle, and authorities obtained the cell phones believed to be used in the scheme, according to Miami police. Four phones in all were recovered, including three from Victor, police said.

Voigt and Victor were both charged with extortion, conspiracy to commit extortion, and unlawful use of a communication device, according to a criminal docket. They have pleaded not guilty.

Prosecutors have obtained the text messages sent to Goddard, but they have been unable to bypass the passcodes on the suspects' phones -- Voigt's iPhone and Victor's BlackBerry -- to search for more evidence.

As such, prosecutors filed a motion asking a circuit court judge to compel the defendants to give their passwords to authorities.

Conze, Voigt's attorney, has opposed that request. He told CNN that compelling a defendant to divulge a passcode in their head was a "slippery slope" in the legal arena.

"I think it's a new frontier," he said. "I do believe that it's eroding the rights that are guaranteed by the US Constitution."

Victor's attorney, Zlejka Bozanic, also opposed the motion, saying that making someone give you their thoughts was a "completely different story" than providing fingerprints or DNA.

"In order to get a password, you have to get the client to say what the password is," Bozanic said. "It's definitely testimonial."

Pleading the Fifth

The Fifth Amendment of the Constitution declares that "No person shall ... be compelled in any criminal case to be a witness against himself."

That right to not incriminate yourself is at the heart of the defendant's rights at a criminal trial. Those accused of a crime can therefore "plead the Fifth," as it's called, and refuse to testify against themselves.

That right also applies to acts that are "testimonial" and have communicative aspects, according to Jennifer Granick, director of civil liberties at the Stanford Center for Internet and Society.

Like giving a password, for example.

"The ultimate question is whether providing a password is testimonial communication," Horowitz said. "In context of a password to a phone, it seems a pretty strong argument that that is" -- and therefore protected by the Fifth Amendment, she said.

However, the government can compel defendants to give up passwords if it's a "foregone conclusion" that prosecutors will find information they already have their hands on, Granick said.

"The government has to show there's incriminating evidence," she said. "They can't unlock a phone and have a fishing expedition."

The Apple-FBI case

Legal rights regarding cell phone passwords have become a prominent legal issue in recent years, notably highlighted by Apple's refusal to allow the FBI into the iPhone of the San Bernardino shooter last year.

Apple argued in court that building a "backdoor" to the iPhone for law enforcement would create privacy issues for its millions of users. The FBI eventually dropped its case when it gained access to the phone via a third-party.

However, that case had no Fifth Amendment issues because the defendant was dead and could not be compelled to do anything. Still, it raised intriguing questions on phone encryption and law enforcement that continue to be relevant in other cases.

"The scope of this is pretty contested now," Granick said. "Courts are struggling through it."

Interestingly, both Granick and Horowitz said that judges have generally ruled that fingerprints, unlike passwords, are not considered "testimonial acts." That means phones that can be unlocked with fingerprints are not protected in the same way as those with passwords.

"I think it's more established, more certain, that you'll be provided better protection under the law using a password than a thumbprint," Horowitz said.