Yes, it is ethical to put military research to the best use we can. Whether logistical systems, trauma medicine, personal weapons, or encryption, all those improve our efficiency, our safety, our leisure, and our privacy.

Wars aside, the military is a place where practical problems are encountered daily, and the solutions battle-tested at scale. It's reasonably safety-minded and cost-aware (spicy anecdotes aside).

Moreover, it's helps a lot when the research isn't walled off by stringent IP regulations.

Yes. You're yourself posting this comment via a medium that was funded by DARPA.

The US Government did not develop Tor, they 'only' funded it. I understand that funding something often effectively imbues a project with whatever mojo the funding org has associated with it. That's certainly not the case here though. Tor's ideals and direction was established and set before said funding, and have remained steadfast since.

To the bigger point:

> But is it ethical to use military-developed innovations?

That's complicated in the real world. Many good, moral things have been created or encouraged by immoral organizations, and vice versa. The US Government has sponsored the development of many different good, useful technologies over the years.

The reverse is true as well, though perhaps to a lesser extent.

That is pretty hilarious to post on the internet, a DARPA developed innovation..

Why does it matter who 'developed' it? The idea always existed in the space of possible ideas. The military-backed researchers just found it first.

You're going to deprive yourself of using it just because of who found it? That makes it pretty easy to deprive you of tools, if someone else using them will stop you from doing so.

Is it ethical to be the beneficiary of the military keeping supply chains safe and keeping supply chains open worldwide?

In this world your existence is "unethical", in regards to a question like that, unless you want to live on a mountain peak above the messiness of ordinary human moral calculation and compromise.

Anyone connected to GPS is guilty of such.

The end of WW2 saw the Americans and Soviets rushing to take over Germany so we could acquire as much Nazi tech and scientists as possible. Our ICBMs technology was based upon this Nazi technology, and now SpaceX and NASA tech is based upon that as well. While the origins of it are based upon a destructive goal, they have enabled the Mars rovers, Moon landing, Hubble telescope, etc. Technology should be evaluated on its own merits and not its origins.