Factorization of RSA-250 (2020)

[ncc-erik]

Found in 2700 core-years, verified in < 1 core-second

    >>> 64135289477071580278790190170577389084825014742943447208116859632024532344630238623598752668347708737661925585694639798853367*33372027594978156556226010605355114227940760344767554666784520987023841729210037080257448673296881877565718986258036932062711 == 2140324650240744961264423072839333563008614715144755017797754920881418023447140136643345519095804679610992851872470914587687396261921557363047454770520805119056493106687691590019759405693457452230589325976697471681738069364894699871578494975937497937
    True

[svnpenn]

That a ratio of 85 billion to 1, ouch

[rwmj]

We're over a 10th of the way to RSA-2048! (joke) https://en.wikipedia.org/wiki/RSA_numbers

[anderskaseorg]

For those who don’t get the joke: RSA-250 is named for the number of decimal digits (250 decimal digits, 829 bits), while RSA-2048 is named for the number of binary digits (617 decimal digits, 2048 bits), so we’re two-fifths of the way by length, not a tenth. On the other hand, given the complexity of current factorization algorithms, RSA-2048 is going to take something like 200 billion times more CPU power; of course, algorithmic and computational advances are likely to decrease that.

The implications for RSA-1024 are more pressing: that’s only going to take about 200 times more CPU power.

[yuliyp]

More like a 40% by that logic. It seems like there's inconsistency around which numbers are counted using decimal digits and which ones are counted using bits. This one is 250 decimal digits, or 829 bits.

[dvh]

I'm trying RSA-896 in a screensaver for about a year, so far I have nothing. The reward for this one is 75k.

[anderskaseorg]

FYI the challenge ended 15 years ago; there are no more cash rewards.

[pvg]

Related, with a bunch of comments that apply

The Factorization of RSA-240, Dec 2019, 36 comments

https://news.ycombinator.com/item?id=21696438

[oasisbob]

According to the message headers, this announcement occurred in February 2020.

[gus_massa]

It was discussed here in 2020 but it didn't get too many comments https://news.ycombinator.com/item?id=22816167 (30 points | April 8, 2020 | 5 comments)

[cabirum]

2700 core-years is about 21 128-core c6i instances, $3.59856/hour each. One year costs about $665000, can be done if one really needs it

[sterlind]

you could probably do it for cheaper using a larger pool of preemptable instances. I think you may end up saving money buying your own blades (21x4 Intel Xeon 32-core CPUs = ~$210K, I'm assuming motherboards + power + ram is less than 3x that.) I didn't factor in AMD's 128-core Epyc processors or Xeon Phis because I don't know enough about their suitability.. do you need AVX-512 for this kind of thing?