There are cryptographic algorithms that can do that. It seems like 
overkill for departmental root passwords though.

On 3/5/2013 1:35 PM, Joe Hourcle wrote:
> On Mar 5, 2013, at 8:29 AM, Adam Constabaris wrote:
>
>> An option is to use a password management program (KeepassX is good because
>> it is cross platform) to store the passwords on the shared drive, although
>> of course you need to distribute the passphrase for it around.
>
> So years ago, when I worked for a university, they wanted us to put all of the root passwords into an envelope, and give them to management to hold.  (we were a Solaris shop, so there actually were root passwords on the boxes, but you had to connect from the console or su to be able to use 'em).
>
> We managed to drag our heels on it, and management forgot about it*, but I had an idea ...
>
> What if there were a way to store the passwords similar to the secret formula in Knight Rider?
>
> Yes, I know, it's an obscure geeky reference, and probably dates me.  The story went that the secret bullet-proof spray on coating wasn't held by any one person; there were three people who each knew part of the formula, and that any two of them had enough knowledge to make it.
>
> For needing 2 of 3 people, the process is simple -- divide it up into 3 parts, and each person has a different missing bit.  This doesn't work for 4 people, though (either needing 2 people, or 3 people to complete it).
>
> You could probably do it for two or three classes of people (eg, you need 1 sysadmin + 1 manager to unlock it), but I'm not sure if there's some method to get an arbitrary "X of Y" people required to unlock.
>
> If anyone has ideas, send 'em to be off-list.  (If other people want the answer, I can aggregate / summarize the results, so I don't end up starting yet another inappropriate out-of-control thread)
>
> ...
>
> Oh, and I was assuming that you'd be using PGP, using the public key to encrypt the passwords, so that anyone could insert / update a password into whatever drop box you had; it'd only be taking stuff out that would require multiple people to combine efforts.
>
> -Joe
>
>
> * or at least, they didn't bring it up again while I was still employed there.
>
>