On Mon, Jun 2, 2008 at 2:51 AM, Manjula Peiris <[EMAIL PROTECTED]> wrote:
> > On Mon, 2008-06-02 at 14:44 +0530, Kaushalye Kapuruge wrote: > > Supun Kamburugamuva wrote: > > > Hi List, > > > > > > At the moment a Rampart/C service can handle single client for signed > > > messages. This is because of the static configuration of the > certificate > > > files. Now Rampart/C supports the PKCS12 key stores. A PKCS12 key store > > > allows the service writer to specify multiple certificates. These > > > certificates can be used by the service to verify weather the actual > > > signature is from a trusted user. > > > > > > This is the proposed way of handling multiple clients in the server > side. > > > Service writer has to create a key store with the certificates of all > the > > > trusted parties. A request has a reference to the certificate that it > used > > > for signing. Usually there are various ways to refer an X509 > certificate. > > > > > > First case is to embed the certificate in the message itself. In this > case > > > the reference will be a direct one. Rampart/C will extract the > certificate > > > from the message and checks weather it is in the certificate store. If > it is > > > in the store it indicates that a trusted user has signed the message. > If the > > > certificate is not in the store the request is rejected. > > In this case do we really need to check the key store ? Because message > is signed using sender's private key and he is sending his certificate > to verify. So we need to verify using that and just need to be sure that > the message is integrity protected by the way to the receiver. > Please consider this scenario. We have a service and we are accepting messages from different clients (We have fixed number of trusted clients that we need to serve). Most of these clients are not users and they are applications. They have a public/private key pair but do not have a user name. Now all of them are signing and sending there messages with their certificate inside the message. This scenario works as far as nobody wants to cheat on us. Now if a unauthorized client wants to access the service it can do that easily by sending a message with its certificate embedded in the message. We don't differentiate between the authorized client and the unauthorized client since we are using whatever certificate embedded inside the message. > And if you are going to check whether the certificate is in the store > how are you going to do that? Because from the message you are getting a > relatively big chunk of a string and finding that in the store may be a > time consuming operation. I mean even if you change it to a some other > format there is an unnecessary overhead. > AFAIK We don't have to parse the whole certificates to get a match. We can use certain attributes of the certificate like issuer serial to check weather we have the certificate in the key store. > > > > In the second case the certificate is not embedded in the message and a > > reference to the certificate is sent. In this case the reference will be > > used to query the PKCS12 key store and if a matching certificate is found it > > will be used to verify the signature of the message. If a match cannot be > > found the message is rejected. > > > > In both these cases the certificate that is loaded in the in path will be > > used for the encryption in the out path. So we are assuming that the > > response is always going to the end point where the message originated. > > > > In the client side the situation is different. Usually a single client will > > talk with a single service. So the existing mechanism is enough to handle > > most of the cases. But if the client wants to change the certificates among > > different requests he should be able to do that. We can easily achieve this > > by introducing a new parameter to the rampart client configuration. > > > I hope you are trying to suggest a way to a scenario, where a client > needs to call the "same service" by using different certificates on > multiple requests. And I'm sorry I do not see a relationship between the > start of the mail and the end. Are you trying to say that we can achieve > above requirement using PKCS12? And what the "parameter" you are trying > to introduce and how exactly that effects the client behavior? > If it's different services then existing features would be enough I > guess. Client needs to change bunch of other parameters apart from the > certificate. > Cheers, > Kaushalye > > > Regards, > > Supun. > > > > > >
