[blahblahblah]

"Supposedly the same argument could apply to a safe combination, hence a defendant cannot be compelled to reveal a combo but can be compelled to open the safe."

Can the defendant even be compelled to open a safe? Suppose you have a case in which the defendant has either specifically disclaimed ownership of the safe in question or disclaims any knowledge of the combination or has flatly refused to either confirm or deny ownership of the safe or knowledge of its combination on fifth amendment grounds. I'm no lawyer, but I suspect the standard procedure in such cases is that the judge issues a warrant that permits police to access the contents of the safe and no burden is placed on the defendant to do anything at all. Rather, because they have a warrant for the contents of the safe, the police are entitled to open it and they do just that, using a locksmith or mechanical means to force it open. The analogous situation with respect to encrypted data would be that the police are welcome to crack the encryption themselves by whatever means they deem appropriate, but the defendant isn't required to do their work for them.

[proexploit]

I believe the police have the right to open the safe, but you aren't required to open it for them. If the police came into your house and said "show us every hidden object" so we can decide if it is illegal. You wouldn't be required to comply.