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This is interesting but it's essentially a protocol attack against a certain type of RSA signature. It talks about PKCS5 not being affected. Says nothing about OAEP which I'd hope also holds up.
So for RSA without padding, a threat actor could request lots of tokens (without getting rate-limited?), and use that as information to more precisely focus efforts to brute-force the key, and thereby reducing the number of operations required to do so? Or am I misunderstanding it?
That's what I think I read as well.
Oh good, more bad news
The practical risk is limited, but still significant. Applying the attack against the deprecated use of 1024-bit keys took a handful of months on an academic CPU cluster, significantly less than the current estimates for 1024-bit factoring that would require resources that only nations or companies with massive resources could achieve. Widely used RSA implementations are also safe.
Bold emphasis is mine. It's a nothing Burger article.
I was "following key length recommendations" 10 years ago that said 3072 bit or higher for RSA. At that time, lightweight processors would struggle a bit with 4096 bit keys, so I've launched a fair number of systems with 3072 bit keys - none of the data on any of them is worth a handful of months on a CPU cluster.
Though, there is an interesting metric you can put on key value today, because so much compute is available for short term lease, you can literally spend $1m for a 50/50 shot at cracking a "very secure" key in a few hours, because you pay per unit of compute, not per hour. Now, Amazon or whoever might start refusing your business if you tried to spend $1M on compute in parallel all running within a single hour, but you could probably negotiate with them to get that done in low demand slots over a couple of days.
Useful information: https://eprint.iacr.org/2026/2131.pdf
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this post was submitted on 25 Sep 2026
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