Re: [gentoo-dev] [PATCH] document openssh-7.0 dsa key change #557388

[Mike Frysinger]

On 13 Aug 2015 09:00, Kristian Fiskerstrand wrote:
> On 08/13/2015 05:17 AM, Mike Frysinger wrote:
> > +Your best option is to generate new keys using newer types such as
> > rsa +or ecdsa or ed25519.  RSA keys will give you the greatest
> > portability +with other clients/servers while ed25519 will get you
> > the best security +with OpenSSH (but requires recent versions of
> > client & server).
>
> Strictly speaking DSA/DSS is newer than RSA (FIPS-186-1 came in early
> 90's, RSA around since 70s, although the ElGamal signature scheme was
> around before that).

i'll rephrase:
-Your best option is to generate new keys using newer types such as rsa
+Your best option is to generate new keys using strong algos such as rsa

> ECC gives a better performance on the same
> security level when comparing to DSA/RSA, however claiming better
> security in general isn't necessarily valid, Ed25519 is a signature
> scheme over Curve25519 which is a 256 bit curve generally considered
> to be 128 bit security level, roughly comparable to a 3072 bit RSA key.

using ed25519 allows you to build openssh w/USE=-ssl which does get you
better security due to the smaller attack surface.  but the point of the
news item is to push people in the right direction w/out getting into a
dissertation on the nuances/details that people realistically won't grok
and won't make a difference to them.  if they're experts/interested, it
should be easy to locate additional material (including the linked page).
-mike