Pretty Good Pollution

My public PGP key is available if you need it. I do not normally sign or encrypt my mail with PGP; the information I send is rarely sensitive enough to warrant encryption, and signing is likely to confuse less experienced computer users. But signing certain files makes sense, and I do want to offer the option of secure communication. By all means get acquainted with PGP or GnuPG if you haven't done so already.

There's another, older key with my name on it available on the keyservers. Don't use it. I placed it there many moons ago while first experimenting with PGP, and have since forgot the passphrase for the corresponding private key. This is unfortunate, because the key that's published there can neither be removed nor used meaningfully.

Since I have forgotten the passphrase I obviously can't prove that it's my public key. Without such proof any request to remove my key from a keyserver must be ignored, or anyone could remove any key. Besides, keyservers copy keys between themselves so even if I somehow managed to convince the operator of one of them to remove my old key, it's probably present on all servers by now. All I can do is to tell people not to use the old key, and hope that any automated tools will ignore it.

The lesson to take home here is not, as you might expect, "don't forget your passphrase". Of course you shouldn't, but in practice that advice is about as useful as "keep backups of your data". It's easier said than done. One thing you can do to minimize the risk of repeating my mistake is to create a key revocation certificate while you still have access to the private key. Store it somewhere safe, preferrably not the same safe place where you store your private key. The revocation certificate will allow you to revoke the public key if you ever lose the private key or forget the passphrase.

Oh, and set an expiration date for your key. If I had done so, the key could at least be removed at some time after my death. Perhaps the point will be moot in a future where quantum computers and/or new algorithmic insights makes public-key cryptography obsolete. On the other hand, inaccessible keys, non-expiring certificates, CRLs, and similar cryptographic detritus may need to hang around for all time on our servers and networks. It could be the digital analogue of nuclear waste, requiring indefinite storage and distribution; it has no half-life.

30 November, 2004