PGP Encryption

[Brian Morrison]

On Tue, 14 Mar 2000 19:39:28 -0400 (AST), Trevor Smith wrote:

>>If a recipient has multiple keys on the key ring for a given addressee
>>it does not allow one to chose the key to be used. It really should do
>>this.
>
>I don't really understand this. Why would a person want multiple PGP
>keys for one email address? I'm sure there is a good reason I just
>need an explanation with a real world example.
>

OK, well let's see. I have both an RSA key (generated with PGP 2.6.3i)
and a DH key (generated with PGP 5.0i). Both of these are on my
keyring. Someone I correspond with has both my public keys, we normally
use our DH keys because of the better security they offer, and the fact
that the signing and encryption keys are distinct. However, I also use
a computer for which the latest PGP available is PGP 2.6.3i, so he
sometimes needs to encrypt using my old RSA key so that I can read my
mail when using that machine.

I also know someone (who runs the International PGP pages in fact) who
has several keys, shown as of low and high security, all with the same
associated address. He can only decrypt the high security key at his
home, but can decrypt the low security key at his place of work. 

As you can see, in both cases it is necessary for the sender to have
both public keys available and have the option which one to use in
given circumstances, does that explain why I would like this?

The way I see it is that the address book could have a tab that allows
all the keys for that address to be selected from a list box,
preferably with the key ID shown. A setting to allow 'select at send
time' would also be useful.

I did ask BoB about this in the past, but he was not inclined to put in
effort due to the decision to sell PMMail on, and as he did not use PGP
himself he was not familiar with the issues surrounding its use.

BTW, your comment about the truly paranoid is not very fair :-). If you
had read the UK's Regulation of Investigatory Powers Bill, currently
going through its committee stages in our parliament, you would know
that it could mean that someone can be jailed for 2 years if they have
a) encrypted material and b) they cannot decrypt it because they have
deleted a key deliberately as part of a key rotation policy. The
ability to have once decrypted it when the key still existed is deemed
to mean that inability to decrypt *now* is a 'refusal' to decrypt. Yes,
I know that this is insane and unworkable and probably violates the
European Convention on Human Rights, but this is the kind of lunacy
that prevails among our Civil Servants and politicians who think that
what they say will make everything all right.

Sorry for the rant....

-- 
Brian Morrison                                  bdm@fenrir.demon.co.uk
              do you know how far this has gone?
               just how damaged have I become?
                                      'Even Deeper' by Nine Inch Nails