Gentoo Archives: gentoo-user

From: lee <lee@××××××××.de>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] broken seamonkey :(
Date: Sun, 13 Sep 2015 14:24:21
Message-Id: 87613eflf7.fsf@heimdali.yagibdah.de
In Reply to: Re: [gentoo-user] broken seamonkey :( by Fernando Rodriguez
1 Fernando Rodriguez <frodriguez.developer@×××××××.com> writes:
2
3 > On Sunday, September 06, 2015 4:29:25 PM lee wrote:
4
5 > [...]
6 >>
7 >> When creating the certificate, I have used the fqdn the host does
8 >> actually have and knows itself by (because I needed to fill in the
9 >> fields, and it seemed most reasonable to use the actual host name).
10 >>
11 >> That this host can be reached at all, via different fqdns and IPs, is a
12 >> matter of network traffic (re-)direction and of how the DNS-entries
13 >> currently happen to be. They are all transparent and irrelevant to the
14 >> user/client and subject to change. Why should they matter for a
15 >> certificate which is supposed to let me figure out whether I'm
16 >> connecting to the host I'm expecting to connect to, or to something
17 >> else?
18 > [...]
19 >
20 > An SSL certificate provides both encryption and authentication. For the
21 > encryption part it's simple, you own the private key, the certificate has the
22 > public key, so only you can decrypt whatever is encrypted with it.
23 >
24 > Authentication is more complicated. It's easy if you think of if like a driver
25 > license. The hostname is like the photo, if I get pulled over and hand over a
26 > stolen license to the officer he'll know it's not me by looking at the photo.
27 > Your browser does the same with the hostname, if somebody steals your private
28 > key they will also have to steal your domain name to impersonate you. If
29 > somebody grabs a hold of your CA's private key is like stealing the DMV
30 > printer, now they can issue themselves a license with your name and their own
31 > picture. But if they hand it over to an officer he will call it in and find out
32 > it's fake, that's the equivalent of revocation lists and ocsp.
33 >
34 > Of course it only works because we trust the DMV (or the CA in this case) to
35 > be diligent in verifying you are who you say you are before issuing a license
36 > or certificate. So it all doesn't apply as much to self issued certificates but
37 > it still applies to some extent.
38
39 Actually, it does not work. What my face looks like is not subject to
40 network traffic (re-)direction and the content of DNS entries. It
41 changes with age and can still be recognized. I could send you a
42 picture of my face and you would never know whose face is on the
43 picture: that's like an FQDN or IP. I could just as well give you an IP
44 address or FQDN to identify myself.
45
46 The purpose of driver licenses is not identification. Anyway, why would
47 I need some sort of document to identify myself if my face would
48 suffice? In practise, the document is more important than the face
49 that's on it.
50
51 IIRC, there is a way with gpg to change the email address(es) of your
52 key. That makes sense because the address is for having the convenience
53 of not needing to specify a key-ID or something else. And that I might
54 be using another email address does not invalidate the key. It's the
55 key itself which is relevant, not what is being used to pick which key
56 to choose.
57
58 Linking a certificate to an FQDN or IP is clutching at straws at best.
59 As my face changes with time, they also do. With documents to identify
60 me, I don't update the picture all the time.
61
62 When the ID-document I currently have expires, I won't have one that
63 hasn't expired because they have become so insanely expensive that I
64 can't afford one. That's similar to the work it would take to put a new
65 certificate in place for all the users just because it's linked to an
66 FQDN/IP. It might be cheaper if you could change out the picture as you
67 can change the email address with gpg.
68
69 The concept is flawed. And how could I myself verify that a CA does its
70 job the way they are supposed to do it? In the end, it's no more than a
71 deception, and that shouldn't be needed to be able to use encrypted
72 connections.
73
74
75 --
76 Again we must be afraid of speaking of daemons for fear that daemons
77 might swallow us. Finally, this fear has become reasonable.