[cfarm-users] Is RSA really insecure?

[Gregor Riepl]

> This is a pet peeve of mine:  unless you have a citation for an actual 
> viable attack on RSA as used in SSH, or perhaps on the protocol SSH uses 
> for RSA-based authentication, this is *not* insecure at all and those 
> changed defaults indicate that either OpenSSH or your distribution is 
> doing something stupid.

Not disagreeing with you here, but the ssh-rsa host key deprecation 
actually has nothing to do with RSA.

It's because it relies on SHA-1, and SHA-1 is known to be broken.

See the details here: https://www.openssh.com/txt/release-8.2