There are two solutions for this. 1) The halting problem is decidable (but untractable) for bounded machines. 2) Instead of deciding when to halt inside the mac

There are two solutions for this. 1) The halting problem is decidable (but untractable) for bounded machines. 2) Instead of deciding when to halt inside the machine, do it outside with continuations. Encrypted computing will always enforce time-limits thus this is not an issue.