GnuPG in the enterprise

[Tony Shadwick]

On Wed, 15 Jun 2005, Dan Nelson wrote:

> In the last episode (Jun 15), Tony Shadwick said:
>> Are there any good documents out there on managing GnuPG in the
>> enterprise?
>>
>> There are basic issues I need to be able to address, such as a
>> situation when an employee leaves a company.  The admin needs to have
>> the rights to revoke that user's public key, and be able decrypt any
>> old messages to that user, and be able to decrypt messages sent to
>> that user that are now being redirected to someone else for handling.
>>
>> Are there established mechanisms for handling centralized key
>> management in a company to where the Administrator has access to
>> everything required?
>
> One solution is to make a copy of all keys (with known passphrases)
> when they are created, and put the copy in a secure location.  If an
> employee leaves suddenly, you can retrieve the key to decrypt leftover
> files and revoke the key.  Pgp.com's Windows PGP software uses special
> Revoker keys and Additional Decryption keys that get added when files
> are signed, so files are always encrypted to multiple recipients and
> keys are always revokable even if the original key no longer exists.
> gpg doesn't recognize ADKs, though.

Just so I'm following then, let's say I have gnupg installed on my server, 
and I'm creating all of my employee's secret keys there, then installing 
gnupg on their workstations so that they can use local mail clients to 
encrypt.

What's to prevent them from chaning their secret key passphrase or 
revoking the key themselves and creating a new public key, then publishing 
that to the keyservers? (Other than knowing enough about gnupg in the 
first place to do any of this of course...)

Not to mention I've always wondering how gnupg plays with multiple 
recipients or internal company mailing lists.  For example if I send a 
message to VIP1, VIP2, and VIP3, and it is an important internal document 
that requires encryption, when I encrypt the message, won't it get 
encrypted with VIP'1 public key, thus VIP2 and VIP3 won't be able to open 
the message?

Sorry to babble, but it really is important to me to get this down and 
documented.  It is very frustrating that I have clients that use no 
encryption on e-mail, even if they are sending sensitive account 
information. (!!!!)