A Florida case that involves a passcode and locked iPhone could have far-reaching, digital-age consequences based on a court's ruling and legal interpretation of the Fifth Amendment of the United States Constitution, which protects citizens against self incrimination.

At stake could be the future of password-protected and encrypted digital data and the privacy rights of the people who use that technology. Depending on the outcome of this and other cases, the issue could become a defining moment in either user privacy or national security. While the Florida case is a state-level decision without jurisdiction nationally, other states such as California also have law enforcement examples that are bending Fifth Amendment interpretations.

Strong authentication today combines something you know and something you have. in a legal sense, those two things are judged separately.

A ruling by the Florida Court of Appeals earlier this month, overturned a trial court ruling that a male suspect did not have to surrender the passcode to his phone after being accused of taking inappropriate pictures of an unsuspecting woman . The court said that would be tantamount to having the suspect testify against himself, which is protected by the Fifth Amendment.

Based on the lower court ruling, police were not able to access the phone or to confirm the existence of any pictures.

The Florida ruling that the Fifth Amendment does not protect the suspect deviates from earlier rulings in similar cases, including Pennsylvania and Colorado. Cases in those states have concluded a passcode or password is something the person knows and therefore would be considered self-incrimination if it were surrendered to law enforcement.

All three cases turned on an argument of "foregone conclusion," meaning law enforcement had already "determined" the contents of the phone before actually confirming what was there. Only the Florida court did not reject the notion of forgone conclusion.

Judge Anthony Black, who issued the ruling for the three-judge panel of the Florida Court of Appeal's Second District , said, "providing the passcode does not 'betray any knowledge [the defendant] may have about the circumstances of the offenses' for which he is charged. Thus, 'compelling a suspect to make a nonfactual statement that facilitates the production of evidence' for which the state has otherwise obtained a warrant based upon evidence independent of the accused's statements linking the accused to the crime does not offend the privilege."

A 1998 decision written by U.S. Supreme Court Justice John Paul Stevens in Doe v. U.S. included the now familiar explanation that an accused person may be "forced to surrender a key to a strongbox containing incriminating documents," but cannot "be compelled to reveal the combination to his wall safe."

To date, the statement by Justice Stevens has been retro-fitted to the digital age, but the outcome of this Fifth Amendment debate could alter the way U.S. citizens protect their phone's content and what they store on them.

The outcome jumped to the headlines with the high-profile case earlier this year between the FBI and Apple. But the battle has been going on for some time.

Earlier this year, the American Civil Liberties Union wrote on its blog that it uncovered 63 confirmed cases and 13 additional cases "in which the government applied for an order under the All Writs Act to compel Apple or Google to provide assistance in accessing data stored on a mobile device." The All Writs Act is the same legal maneuver used in the Apple-FBI tangle.

"The FBI wants you to think that it will use the All Writs Act only in extraordinary cases to force tech companies to assist in the unlocking of phones. Turns out, these kinds of orders have actually become quite ordinary," the ACLU said in the blog.

Going forward, seizure of phones by law enforcement and searches of the digital content may work their way into law. If so, those decisions will have to consider how information is collected and what information is collected in order to form a digital-age definition of the Fifth Amendment.