(This has ended up longer than I intended, largely because I felt I should then get into why. I'm aware I haven't got into all the nuances, so I hope readers familiar with the area will appreciate this is the compact version.)
Thorsten had a rant last week about PGP keysigning problems. He apologises for his tone, but that's not the issue I take with his rant.
It starts "Keysigning is useless". And yet his complaints seem to be:
- Dealing with the private half of your GPG key securely involves some faff (in this case booting with a live CD and having to set things up ready to keysign).
- He doesn't get on with caff.
- People reject email from machines with invalid HELOs and perform other anti spam measures on ISP access ranges (I'm not clear if it's just greylisting or outright rejects as that's not made clear).
- PGP/MIME is a protocol violation (yes, but it's much better than inline OpenPGP. Unless you have to deal with RT, which mangles it. *sigh*)
Torsten does say that he'll continue to do keysigning on a per-person basis, so it doesn't sound like he's completely given up. I'm posting this largely so other Debian related people don't get the idea that it's not important to think about keysigning.
Why should we care?
Firstly, let's clarify what I mean when I sign someone else's key. If I sign your key then I think that I believe you hold the private part of a key that has your name and an email address I believe I can use to contact you on it. It means I have seen government issued ID that matches that name. It also means that I have interacted with you (and watched others interact with you) under that persona. In short I am happy that the key is a reasonable digital representation of your identity - something signed by it either comes from you or has involved the key being compromised or you coerced into using it against your will.
Why is this useful?
It gets useful thanks to the web of trust; ie the idea that there are a bunch of people I trust partially to sign other keys, and if enough of them have signed a key then I can have a reasonable expectation that the key belongs to the person I want to talk to. Which means I might be prepared to send private data to them. Or Debian might be prepared to accept an upload from them. Which, when you're dealing with a community that spans the planet and where most of the contributors haven't met each other, is pretty freakin' useful - I, as part of Debian's keyring team, don't need to personally be able to identify every Debian developer. All I need to do is be able to trust other DDs to be able to do so. (Though maybe I'm missing out on something here - perhaps Debian should be paying for Gunnar and me to travel the world verifying fingerprints. \o/)
(I still do mass keysignings btw. I'm picky about which keys I actually sign - this is in no way intended as a slight against those I don't, but a mass keysigning at least lets me know that the people involved are happy to exchange fingerprints. Though, FWIW, I normally have ID on me and frequently have fingerprint slips, so if you know me and want me to sign your key/want to sign mine then by all means ask me when you see me!)