It was known for a while to move away from SHA-1. Any TLS certificates using SHA-1 were supposed to become invalid on January 1st.
But I wasn't expecting that google's 110 GPU-year work meant that we could create colliding PDFs on demand.
But I wasn't expecting that google's 110 GPU-year work meant that we could create colliding PDFs on demand.
Usually its when we hit "It's broken" that average Joe developer/operator/etc starts to form their migration plan, and usually they have some time before the attack becomes reasonable to execute outside of pure research / "nation state" attacks.. It seems that block of time was just a few days (a day?!) for SHA1.
And it's that, even if we're talking about an easy to abuse format like PDFs apparently are, that makes me question what just happened? Was sha1 secretly terrible? was the research just that good? or was there some other factor that allowed this to happen?
Also, sure, the major browsers have a date for SHA1 as a TLS signature hash retirement.. But SHA1 is used for a whole pile of other stuff with absolutely no transition plan! January 1st was absolutely never going to be the last day people used SHA1.