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Comment by jsn | Hacker News Reader

Say what? scp is perfectly secure (not open to man-in-the-middle attack) without transferring any keys or using any PKI. scp (just like ssh) asks you to verify remote key fingerprint on first connect.

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This only works if you know the remote key fingerprint in the first place. If you're setting up new servers, it could potentially be compromised.

But that is being ultra-paranoid in my book.

If you're setting up a new server, you either have physical access and can use a keyboard and monitor to look it up, or it's hosted by people you are paying to do such things as tell you the key fingerprint.

Just to be clear mbreese is talking about if you have just set up a new server like a vps and when you first ssh/scp to the server you accept a compromised key such as through a MITM attack but as he said this is highly unlikely to occur.

I setup a VPS on Linode, and they actually added the SSH RSA/DSA key for the 'admin console' login (Lish) when I asked about it on IRC. So, for first-time setup, you can lookup _that_ key, then from there, lookup the system key itself. This avoids a compromised key, at least from you to Linode.

Hopefully Linode doesn't have any internal gremlins.

Of course, the weak point there is SSL where the keys themselves are transmitted, but it did well to quell my paranoia.

1. If you are setting up servers, you don't need to transfer private keys anyway. You may want to transfer client public key to server, but that is absolutely unrelated to man-in-the-middle, paranoia or anything.

2. If you are setting up servers, you may want to transfer the server public (not private) key to client, but what's the point? Ssh/scp will do it for you anyway, and you already know the remote end public key fingerprint anyway -- since you are setting it up.

So, no, "ultra-paranoid" doesn't explain the pastes in question. "Ultra-ignorant" does :)

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