Hi, On Tue, Mar 4, 2014 at 10:49 PM, pietrek -- <pietre...@gmail.com> wrote:
> [...] I think we could add option "--dh none" or "--no-dh". It may be > specified, if user knows what he's doing. > I like that idea. It offers a migration path for users that really want to skip the DH-stuff. I'd vote for "--dh '[none]'", as it does not add a new option (openvpn has more then enough options ;) ), and is hard to accidentally supply as a file name. This is more a usability thing then a crypto thing, so I'd like to hear more opinions on this. > Option --no-ecdh( or --ecdh none ) could be useful if user does not want > to use ECDH for some reason. > I do not like this one. A user gets ECDH initialisation for free, and if a power user really wants to disable ECDH, (s)he can use --tls-cipher "DEFAULT:!EXP:!ECDH" or something like that. An explicit extra option adds code, while it is not needed for the functionality. > Also, to avoid unexpected behaviour like fallback into RSA, we could > force openssl to use DH or ECDH only. > Do you have any idea on how to achieve this, other than setting explicit tls-cipher lists? The cipher list has a limited interface, which would result in actively maintaining a list of 'approved' ciphers within the OpenVPN codebase. I would not like to do that. Regards, -Steffan
