coco coco wrote:
My apologies if this is not really an openssl question. Just want to get some ideas from the gurus here.There is this company (a so-called partner) which has hired an external security consultant to oversee the security of a project which makes use of crypto quite heavily. The security consultant didn't do anything else, except coming up with a scheme that requires that every key must have two certificates, one certificate used for encryption and the other used for signature. The key and certificates are stored in a USB token. The reason from the so-called security consultant was that it is more secure this way. And he got the backup from the CEO (well, the CEO brought him in).We called it bullshit, and were having a hot debate, most people (the technical people) are opposed to that, saying that there is nothing secure about this scheme. If you want to separate the signature key from the encryption key, you should have 2 keys, and not one key with 2 certificates. This does not make any sense.The CEO said he trusts the "security expert", and if we want to change that, we need to come up with better arguments than that.It does not affect us too much, as we just need to modify little portion of our code (mostly java) to handle the double-certificates thingy. But the annoying thing is, the 2 certificates do not even specify usage attributes correctly. And our security expert said it does not matter, we (the programmers) have to figure that out, which cert is used for signature and which one is used for encryption. We do all kinds of tricks to handle that, and it's not even reliable.And the bad thing is that he also wants to re-engineer all other existing applications to use this double-cert scheme. Even worse, the consultant from the local CA also supports that scheme, because (well, that's understandable) the CA got to sell two certs to each user.What do you think?
The prime argument against this scheme is, that it is more work (and costs more money) doing it. So the argument should be the other way round, that is why does this scheme make things more secure? It may depend on the things you are doing with the certificates/keys, but I have not managed to imagine a scenario where using two different certs (especially if issued by the same CA) for the same key do increase security...
But I'm afraid that if the CEO trusts the security guy more than he trusts you, and he wants to spend the money ("we have increased investments in security by 50%") you'll have a hard time finding better arguments... :-\
coco
Hope it helps Ted ;) -- PGP Public Key Information Download complete Key from http://www.convey.de/ted/tedkey_convey.asc Key fingerprint = 31B0 E029 BCF9 6605 DAC1 B2E1 0CC8 70F4 7AFB 8D26
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