Can I decode my DVD collection now?
DVD encryption doesn’t use RSA; and yes, you could since late 1999 already.
RSA-260 Factorized
11–20 of 82 posts
Re: RSA-260 Factorized
#12It's sort of fun to remember the genuine worry in the community around RSA and the (really, really shocking at the time!) progress in factorization leading up to GNFS techniques. Like, it really looked like everything was going to fall apart. We all rushed to 1024 bit keys, and then to 2048 bit after what felt like a few months. And... maybe even that wouldn't be enough? And actual history ended up being the boring v…
ECC does have the benefit of smaller keys, but yes, RSA seems fine security-wise for the foreseeable future.
Re: RSA-260 Factorized
#13Impressive. I wonder the methodology. Algorithmic improvements? More probably just an implementational optimisation. Last RSA record was due to special q sieving methods if I recall well, some 3k core hours. I hope there’s a theoretical improvement behind the result.
So RSA 260 is about 2-3 times harder than RSA 250, which was solved in 2700 core hours in 2020, so it’s probably no algorithmic improvements, just a tweak here and there plus faster hardware.
2700 core years
Re: RSA-260 Factorized
#14It's sort of fun to remember the genuine worry in the community around RSA and the (really, really shocking at the time!) progress in factorization leading up to GNFS techniques. Like, it really looked like everything was going to fall apart. We all rushed to 1024 bit keys, and then to 2048 bit after what felt like a few months. And... maybe even that wouldn't be enough? And actual history ended up being the boring v…
RSA might be fine mathematically but as a production cryptosystem it’s an unmitigated disaster by modern standards.
Compared to elliptic curves, it is comically easy to build an RSA implementation which is catastrophically broken. Both the number of and subtlety of footguns in RSA are extreme.
Even ignoring that, ECC is far more efficient (in part thanks to smaller key sizes and being able to be done with fixed-width arithmetic rather than needing bignums) and far better suited for embedded devices. Migration has been an enormous win even if you think the security of RSA is fine.
Re: RSA-260 Factorized
#15It's sort of fun to remember the genuine worry in the community around RSA and the (really, really shocking at the time!) progress in factorization leading up to GNFS techniques. Like, it really looked like everything was going to fall apart. We all rushed to 1024 bit keys, and then to 2048 bit after what felt like a few months. And... maybe even that wouldn't be enough? And actual history ended up being the boring v…
the researchers from the RSA-250 record have publicly claimed that factoring 1024-bit RSA keys is within reach of nation states. Your 1024 bit key is only "fine" because you are a small fry, not because cryptographers think it cannot be attacked. This would be true if you used a (non-standard) RSA-768 parameterization as well, which is easier than what we are talking about on this post.
It's also worth mentioning the main concern for RSA is not GNFS, but something stronger. SOTA RSA attacks (such as GNFS) use "index calculus". You can also use index calculus to attack finite field diffie hellman. In the 2010's, there was remarkable progress in index calculus attacks against finite field DH in the small characteristic case. For example, the current record for binary characteristic finite field DH is ~30k bits (and this is by an academic --- a nation state could definitely do more).
It is not known that similar progress is possible in other cases (such as for RSA). But it's very much possible that factoring is much easier than expected. Simultaneously I wouldn't personally bet money on it, and if that breakthrough happened, there were sufficient warning signs that I would feel justified in saying "told you so" to people trusting RSA.
Re: RSA-260 Factorized
#16It's sort of fun to remember the genuine worry in the community around RSA and the (really, really shocking at the time!) progress in factorization leading up to GNFS techniques. Like, it really looked like everything was going to fall apart. We all rushed to 1024 bit keys, and then to 2048 bit after what felt like a few months. And... maybe even that wouldn't be enough? And actual history ended up being the boring v…
You can just send the gnupg box and keys to me, I will hold them securely for you so you don't have to worry about it
Re: RSA-260 Factorized
#17Impressive. I wonder the methodology. Algorithmic improvements? More probably just an implementational optimisation. Last RSA record was due to special q sieving methods if I recall well, some 3k core hours. I hope there’s a theoretical improvement behind the result.
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Re: RSA-260 Factorized
#18Impressive. I wonder the methodology. Algorithmic improvements? More probably just an implementational optimisation. Last RSA record was due to special q sieving methods if I recall well, some 3k core hours. I hope there’s a theoretical improvement behind the result.
[dead]
Re: RSA-260 Factorized
#19It's sort of fun to remember the genuine worry in the community around RSA and the (really, really shocking at the time!) progress in factorization leading up to GNFS techniques. Like, it really looked like everything was going to fall apart. We all rushed to 1024 bit keys, and then to 2048 bit after what felt like a few months. And... maybe even that wouldn't be enough? And actual history ended up being the boring v…
the researchers from the RSA-250 record have publicly claimed that factoring 1024-bit RSA keys is within reach of nation states. Your 1024 bit key is only "fine" because you are a small fry, not because cryptographers think it cannot be attacked. This would be true if you used a (non-standard) RSA-768 parameterization as well, which is easier than what we are talking about on this post. It's also worth mentioning the…
> Your 1024 bit key is only "fine" because you are a small fry, not because cryptographers think it cannot be attacked.
This is falling for an xkcd 538 fallacy, btw. Nation states obviously have vast higher capability to subvert individual data than brute forcing its crypto. I stand by what I said: 1024-bit RSA keys are "fine" and will remain so. RSA-309 will not fall within our lifetime.
> it's very much possible that factoring is much easier than expected
And this is sort of toothless? I mean, that's true for ECC too. It's true for all cryptography. It's true for all software. For all engineering. For all math. We'll never know what we don't know. New discoveries tomorrow may upend everything any given property ("safety" is just one) we think our existing machines hold.
But they probably won't. And the moments where that happens are extremely rare. And to be blunt RSA already got hit with that particular lightning bolt.
Re: RSA-260 Factorized
#20It's sort of fun to remember the genuine worry in the community around RSA and the (really, really shocking at the time!) progress in factorization leading up to GNFS techniques. Like, it really looked like everything was going to fall apart. We all rushed to 1024 bit keys, and then to 2048 bit after what felt like a few months. And... maybe even that wouldn't be enough? And actual history ended up being the boring v…
Peter Shor would like to have a word with you...