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verified publisher icon jtesta

please downgrade aes192-ctr to optional

Open perkelix opened this issue 11 months ago • 4 comments

Would it be possible to downgrade aes192-ctr to merely optional? IMHO, if a policy has aes256-ctr, it ought to fullfil the requirement for a strong CTR.

perkelix avatar Jan 26 '25 11:01 perkelix

You'd like to make it optional in which policy?

jtesta avatar Apr 18 '25 23:04 jtesta

In all of them. I would treat aes192-ctr the same as ssh-audit currently treats cert-v01 variants as merely nice to have.

perkelix avatar Apr 19 '25 09:04 perkelix

As far as I know, CTR mode doesn't have any problems. Sure, it doesn't include built-in integrity, but it would still work well as a fall-back. And 192-bit CTR is a good balance of higher security while still having pretty decent performance.

Looking at the Ubuntu 24 Server policy, [email protected] and [email protected] have priority over the third choice (aes256-ctr). I think that means well over 95% of connections won't use CTR mode, since those first two algorithms are wildly popular.

jtesta avatar Aug 30 '25 20:08 jtesta

The point is that a policy should fail just because the 192-bit variant was omitted.

perkelix avatar Aug 31 '25 03:08 perkelix