[Telepathy] Secure communications with Telepathy

[mikhail.zabaluev at nokia.com]

Hi,

>-----Original Message-----
>From: telepathy-bounces at lists.freedesktop.org 
>[mailto:telepathy-bounces at lists.freedesktop.org] On Behalf Of 
>ext Marco Barisione
>Sent: Tuesday, November 27, 2007 4:32 PM
>To: Telepathy
>Subject: [Telepathy] Secure communications with Telepathy
>
>We are working on SSL in gibber and now we need a way to send/receive
>certificates and to send the private key to the cm.
>
>At the moment, my only idea is:
>- The user certificate is passed as a connection parameter to
>RequestConnection().
>- When the connection is established with the server (of course not in
>salut), the cm emits CertificateReceived(handle, cert_type, cert) with
>handle set to 0. The client can verify the certificate and drop the
>connection if something is wrong.
>- For end-to-end encryption, the cm emits CertificateReceived() when
>beginning a communication with a peer with the handle of the peer as
>first argument.
>
>The actual verification of the certificate (maybe with user input) is
>left to the client.
>
>This solution has a number of problems:
>- How should I pass the private key to the cm? Is it a problem to pass
>it on dbus (it could be easily sniffed using dbus-monitor)?

If somebody can attach to your session bus, they probably can just as well read your private keys.

>- What to do if I don't have access to the private key (e.g. smart card
>readers)?
>- In the case of a connection to a server I need to pause the 
>connection
>process until the client has verified the server's 
>certificate, to avoid
>sending the password to an untrusted server.
>- We need a ListSupportedCertificates() method to know the supported
>certificate types: X.509, PGP, etc.

Is it some interface not currently in the spec?

>Any better idea? Suggestions?

We really need some generic security interface on channels. I think that in order to be flexible and cover the use cases already known (e.g. SIP request authentication, end-to-end encryption), it should unify text-based authentication and certificate exchange mechanisms.

Best regards,
  Mikhail