Mr. Smith and Mr. Jones tell police that Billy has admitted to them (on separate occasions) that he (Billy) has child pornography on his computer. Police obtain a search warrant, backed by probable cause, to search Billy's computer. 

When computer experts seize the computer and "activate" it at the lab they find that the files are encrypted. 

The grand jury serves Billy by with a subpoena that orders him to enter the password to "decrypt" the files so that grand jurors can actually see what's in the files. 

Will the grand jury's subpoena be upheld by the courts?