Of course, the Constitution was drafted centuries before the invention of the computer and the internet. And although the framers could not have predicted these innovations, they wrote the Constitution in such a way that our Fifth Amendment protections may apply to computers generally and security encryption specifically.
In recent years, a number of high-profile criminal cases have involved evidence that law enforcement agencies could not access because it was encrypted. Some of these cases involved alleged possession of child pornography, while others involved alleged white-collar crime.
After being unable to decrypt data themselves, law enforcement agencies have sometimes tried to compel defendants to decrypt their own personal data and hand it over. Thankfully, these actions are often challenged by the American Civil Liberties Union and other groups, calling them violations of the Fifth Amendment.
Recently, the ACLU and a group called the Electronic Frontier Foundation filed a joint amicus brief in support of a defendant charged with forgery and for his alleged involvement in a mortgage-fraud scheme. A superior court judge originally ruled against compelling the defendant to decrypt the data. The case was appealed to the state Supreme Court, and the brief was filed to encourage the court to uphold the lower court's ruling.
What's particularly interesting about encryption is that it's not the same as simply locking information up to be unlocked later by a code or combination. Rather, "it scrambles the data into an unreadable format," the brief argues. Therefore, "compelling someone to decrypt electronic data amounts to a command to explain the data."
Hopefully, this and other decryption-related cases will yield rulings that strengthen Fifth Amendment protections rather than weaken them. If law enforcement agencies can crack encrypted data on their own, that's just good crime fighting. But if they are allowed to force defendants to provide evidence to incriminate themselves, that's a slippery slope that could endanger the rights of every American.
Source: Courthouse News Service, "Forced Decryption Fought as Self-Incrimination," Jack Bouboushian, Nov. 1, 2013