David,

> Making secret_onion_key and secret_onion_key_ntor read-only does not quite work, because tor first renames them to secret_onion_key.old and secret_onion_key_ntor.old before writing new files. (Making the *.old files read-only does not work either, because the `tor_rename` function first unlinks the destination.)
https://gitweb.torproject.org/tor.git/tree/src/feature/relay/router.c?h=tor-0.4.6.9#n497

> But a slight variation does work: make secret_onion_key.old and secret_onion_key_ntor.old *directories*, so that tor_rename cannot rename a file over them. It does result in an hourly `BUG` stack trace, but otherwise it seems effective.

Directories instead of read-only files. Nice Out-Of-The-Box Thinking!

Now, the question becomes whether there are any adverse side-effects, with the DirectoryAuthorities, from the secret_onion_keys not being updated over time?

Excellent Work!

Much Respect.

Gary

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