Per my other reply, the case he was dissenting about was not about being compelled to provide the combination for a lock. The dissent simply contained a supreme court judge's opinion regarding combination locks. If you can find actual caselaw for combination locks, I'll take it. Otherwise, I'll take the supreme court justice's opinion.

The other eight unanimously agreed with him, they disagreed that the particular case was analogous to a combination, the other justices were of the opinion that it was really a "key".