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Is The Public Key Infrastructure Outdated?
dchat writes: "Roger Clarke, Visiting Fellow, Faculty of Engineering and Information Technology at the Australian National University claims that the "Conventional, hierarchical PKI, built around the ISO standard X.509, has been, and will continue to be, a substantial failure", and then he goes on to explain why.
I'd be interested in the views of Slashdot users, as my organisation is contemplating considerable investment in X.500 and PKI (including X.509)." Lots to read here.
I believe that what eventually will to evolve is a whole bunch of little problem-domain-specific public-key infrastructures, some of which will use x.509 certificate formats, some of which won't. pgp, ssh, secure dns, etc, all "do their own thing" and provide a public key infrastructure to attempt to solve the piece of the problem they care about without getting tangled into the morass of hierarchical PKI which caused Privacy Enhanced Mail (PEM) to sink without a trace..
I work writing code for one of the major players in the PKI space. Without mentioning any names, or making any plugs, I would advise you to think longand hard about what you are trying to accomplished with PKI and why. A lot of the existing products on the market are more interested in domination of the market, and less on being the transparent (if elaborate) infrastructure PKI was designed to be. PKI should be as dependable and transparent as any of the other internet "specs" when done right. Of course, history has shown that nothing is ever that simple, just look at the wars being fought over Java or the ones over HTML (which have died down to some extent.) PKI works well for those who are willing to suffer the pains of being an early adopter. Micro$oft and Netscape browsers don't parse certs the same. (Sadly, I have to admit that M$ is ahead in this area.) The major vendors often have interperated the specs just differently enough to make interoptability a major problem. My advice is to find a product which fits your present needs, and seems to offer the flexibility to expand into the future. The flexibility is going to require a willingness to play nicely with others and to intergrate with existing apps. Stay away from total end-to-end solutions. You are not looking for a "structure" but an "infra-structure". For all the complexity, PKI is likely to become much more wide spread due simply to the demand being placed on the internet by cooperations. IPSec and smart cards are becoming a reality, and the best way to manage those is PKI. The other benefit here is that with physical smart cards, private key theft is nearly impossible. (The only exploits I know of involve physical access, and LOTS of equipment beyond the reach of the average skript kiddie) As PKI becomes more widely deployed, it's providers will be force to become more standardized or get out of the game. Just like with the Web, early adopters had a lot of headaches with different browsers HTML parsers, image formats, etc... but these days those issues have mostly been dealt with, and the early adopters now have a stronger business because of longer term involvement in the medium.
Either Clarke generalizes problems to all deployments of PKI, or he blames PKI for wider 'security is just plain hard' problems.
Here's some examples:
- In 3.2 he describes a long list of proposed requirements to prove identity. This is interesting, but avoids the plain fact that proving identity is not only a problem for PKI. Besides, many corporate implementations of PKI issue building-access badges to users with similar proof-of-identity requirements. Is it too much to ask to issue a smartcard at the same time? No, institutions do this today.
- He claims that PKI implies one trusted root. Wrong. Look in your browser for about 30. You can decide to trust or not trust each of them. You can add new ones.
- He claims that conventional PKI has a string of restrictions which are basically choices made by the implementor of a particular PKI deployment. Out of this list, I have only ever seen 3:
- In 4, he claims that it's possible to steal keys by breaking into a server. Again, that's up to the deployment. We recommend that keys are stored on hardware tokens. Plain and simple. Most devices do not provide for a facility to remove a key from a hardware token.
- "Private keys are susceptible to a vast array of risks, both of capture, and of invocation without the authority of, or even knowledge of, the consumer/citizen. - bunk. Plus, the rest of the paragraph doesn't really support this sentence anyway.
- In 5, he says that the Name Space has to be well managed and requires cooperation of different entities. Not true. Thawte and Verisign did not have to cooperate before because they had different roots. This is a point he doesn't seem to understand at all.
- dot, dot, dot
...
There are many ways to set up a PKI. You can set up a PKI with any or all of the problems Clarke cites. That would be the wrong way- "a certificate that expressly claims to 'bind' the key to a person" - this depends on how well the RA authenticates the user. An intrinsic problem with any organization issuing credentials - not just PKI.
- little or no choice as to who will issue the token - This is understandable, since the PKI group in an organization will typcially have determined the most appropriate security class of tokens for the deplyoment.
- Little or no choice in the organisation from which the individual acquires a certificate - again, up to the individual deployment.
All of the other items are plain not true. And any organization who does keygen on behalf of a user is plain dumb.With a little more work, his paper could have been a very constructive HOWTO, to inform the reader how to set up a good PKI. However, he just rants on about problems, none of which are unique to PKI, without providing the solutions, most of which are well known.
His paper should be titled "Pitfalls to avoid when setting up a PKI".