I'm trying to understand and evaluate the security impact of DH in TLS.
As far as I can tell, there are four major different implementations of DH in TLS.
With the ephemeral DH's, forward secrecy is possible, which I consider a huge bonus to security.
What I'm not too sure about is the elliptic curve part. With elliptic curves, the public certificate (?), used for DH, can be smaller than without elliptic curves and still be considered secure.
I have something in my mind like, non-elliptic-curve DH should have at least 2048 bit, to be considered secure.
Is my information correct?
How can I determine the key length (or public certificate size, I'm not sure what exactly I'm looking for here), of my server?
Can I use the information from the .pem file, used for DH (see comment below)?
openssl dhparam -inform PEM -in ./file.pem -check -text DH Parameters: (4096 bit) prime: [...] generator: 2 (0x2) DH parameters appear to be ok. -----BEGIN DH PARAMETERS----- [...] -----END DH PARAMETERS-----
So in this case the DH key length/public certificate size would be 4096, correct?