RE: Revoking Old Lost Keys
At 09:47 AM 1/6/96 -0000, Frank O'Dwyer wrote:
On Saturday, January 06, 1996 09:18, Timothy C. May[SMTP:tcmay@got.net] wrote:
At 7:07 AM 1/6/96, Bruce Baugh wrote:
I'd like to bring up a problem I haven't seen addressed much yet, and which I think is going to come up with increasing frequency as PGP use spreads.
The problem is this: how can one spread the word that an old key is no longer to be used when one no longer has the pass phrase, and cannot therefore create a revocation certificate?
Basically, you are screwed. Any revocation you attempt will not be trusted, as we will suspect the new "you" to be an attacker, perhaps an agent of the NSA or the Illuminati. In the view that "you are your key," the old you no longer exists.
This is true, but the "old you" can be resurrected if you can get enough people to believe your new key using any out-of-band means available to you. You can also put a comment in your new key's uid explaining the problem and how to verify the new key. You will find it very hard to use this new key for a while, though, during the transition period. Many people will take the existence of two keys with the same uid as suspicious in itself, since it at least indicates some kind of attack (even if only a denial of service attack). There are times when you want multiple keys with the same ID. I have two key sizes becuase one is an older key. I keep it around for use with people who are using versions that do not support the larger keys. (I have run into this once from a sometimes user of PGP. He finally upgraded.) To aleviate the suspicion, I have the two keys sign each other.
This is really a usability flaw with current PGP.
The PGP formats do allow for a 'revocation' certificate, but PGP doesn't implement it (yet, I guess). In any case, it's not really strong enough, since what it says is "I retract all my previous statements that this key is related to this user". This'd mean that you'd have to visit everyone who'd ever signed your key and get them to issue this retraction. What would be needed for this problem is either an "anti-certificate" ("This key does not belong to this user"), or else some convention. For example, if two _trusted_ keys are found for the same uid, the most recent one could be chosen, and the earlier one be purged from keyservers, etc. This may be possible with current PGP. I haven't
Only if you use the name to refer to the key and not the hex ID. (I found out the hard way that some front ends use either the last key created or whatever they feel like for signing keys and/or signing messages. I am still trying to straighten out some of the weird results of that.) Fortunatly, some programs will use the hex ID to refer to the key so there is no confusion. tried it,
but since I have some keys which have fallen into disuse, I will need to do so sometime.).
Revocations are supported, but they require the passphrase. (I have a number of revokations on my keyring from various folks.) The problem here is occasions where you have forgotten the passphrase. (I have an old keyring that I need to go and revoke all of the old keys on it. I have not used them in a year or two. I doubt if they are even on the keyserver...) Eventually there will be a way of revoking keys in the circumstance. Something similar to a notary (or a combination of notaries) who can vouch and say "hey, this guy really did lose his keys". Alan Olsen -- alano@teleport.com -- Contract Web Design & Instruction `finger -l alano@teleport.com` for PGP 2.6.2 key http://www.teleport.com/~alano/ "Governments are potholes on the Information Superhighway." - Not TCMay
There hav been a lot of replies to the original question, but I think a lot of people are missing a simple solution.
At 7:07 AM 1/6/96, Bruce Baugh wrote:
I'd like to bring up a problem I haven't seen addressed much yet, and whic h I think is going to come up with increasing frequency as PGP use spreads.
The problem is this: how can one spread the word that an old key is no longer to be used when one no longer has the pass phrase, and cannot therefore create a revocation certificate?
You create a revocation certificate at the time you create the key, and store it somewhere (I'd recommend putting it on a floppy). Then either give it to your lawyer, with a note saying "If I forget the passphrase, give me back this", or just write a note to yourself, and store it in a place where you'll find it when the time comes. It is inconvenient if a nasty third party finds it while you were still using the key, but much less damaging than if they found the password. (Someone wrote that PGP doesn't support revocation certificates. This is not correct.) Greg. Greg Rose INTERNET: greg_rose@sydney.sterling.com Sterling Software VOICE: +61-2-9975 4777 FAX: +61-2-9975 2921 28 Rodborough Rd. http://www.sydney.sterling.com:8080/~ggr/ French's Forest 35 0A 79 7D 5E 21 8D 47 E3 53 75 66 AC FB D9 45 NSW 2086 Australia. co-mod sci.crypt.research, USENIX Director.
participants (2)
-
Alan Olsen -
Greg Rose