There is no question of law enforcement’s authority to access data on an encrypted hard drive. That part is settled law. the question before the court is whether the defendant could be compelled to decrypt it for the FBI or whether they would have make the attempt themselves. Even the NSA can take months to get past some of the new encryption keys and some systems are set to wipe them selves clean if attempts are made to crack them. The judge ruled that process of decrypting the data did not constitute self incrimination. Once decrypted, the FBI can use the data against her but can not use the fact that she did or did not cooperate in decrypting it. Now however, she could be held in contempt of court and confined until she cooperates.