When you have a panel of judges, we go with the decision of the majority of judges. The decision of the minority of the judges is still published under the heading "dissent." It isn't the ruling and it doesn't affect the law, but it's published just to note that they disagreed and their reasons.
There are some 5th amendment encryption cases where there is a question about whether the government has shown that there is a reasonable certainty that the files contain the evidence being sought. In those cases the 5th amendment would act to protect the info. That doesn't seem to be the case here and in that case, it seems like clear law that he would have to give up the data.
And don't complain too me that it's essentially the same thing; this is the judge's reasoning, not mine.
https://supreme.justia.com/cases/federal/us/487/201/case.htm...
"""
JUSTICE STEVENS, dissenting.
A defendant can be compelled to produce material evidence that is incriminating. Fingerprints, blood samples, voice exemplars, handwriting specimens, or other items of physical evidence may be extracted from a defendant against his will. But can he be compelled to use his mind to assist the prosecution in convicting him of a crime? I think not. He may in some cases be forced to surrender a key to a strongbox containing incriminating documents, but I do not believe he can be compelled to reveal the combination to his wall safe -- by word or deed.
"""