why is SHA1 used? How do I get SHA256 to be used?

[Robert J. Hansen]

You're arguing two different contradictory things here:

> I'm not saying these attacks exist practically today against SHA1 (i
> don't know if they do), but collision-resistance is the relevant
> property, not resistance to pre-image attacks.

And then:

> The places where it is thoroughly "baked in" are the MDC (not relevant
> cryptographically) and the V4 fingerprint (where the relevant property
> is resistance to a preimage attack instead of resistance to generated
> collisions.

The relevant property can be resistance to preimage attack or it can be
collision resistance.  Pick a property and argue it, please.  :)

I am far more concerned about preimage attacks (which are the ultimate
game-over) than random collisions (which affect a smaller fraction of
the userbase).  I'm not saying that random collisions are not troubling
in their own right.

> Where exactly has the original poster signed anything over an MD5 digest?

Refer to my subsequent message, where I backed off from that statement
and clarified I was referring to the poster was already relying on the
safety of SHA-1 -- and was just in denial about it.

If you believe SHA-1 is insecure and you want to avoid it at all costs,
you need to avoid OpenPGP.

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