Earlier quoted context omitted.
To answer your question directly: Both Arq and Time Machine create differential backups. Thus, any particular backup can be restored back in time. However, Arq targets non-file-based media (although you could trick it by a little SSH magic). Time Machine requires file-based access. If ransomeware finds your file-based backup, it will encrypt it and render your backup useless. The term backup gets bandied about, so it…
That doesn't answer my question at all.
Yes arq will protect you from ransomware. Time Machine will not.
both backup differences only. So with arq you just pick a backup before everything was encrypted. With Time Machine the problem is your hard drive is on the same machine that's been infected so that hard drive will be encrypted as well.
Arq doesn't have that problem since the data is in the cloud. The ransomeware doesn't have write access to that data, at most it has indirect append access since arq will start backing up the encrypted files. Which is why you'll be able to just pick a version of the backup before anything was encrypted.
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that is until there is ransomware that checks for arq and tells it to delete all your cloud data :(