I am not a cryptography expert but I am interested in the field. Having said that: I am lately having an hard time understanding the actual strength of a crypto suite based on the underlying problem, the sized of the material and the computation strength needed to break it either via optimization and parallelism capabilities.

> The Web PKI deprecated 1024-bit RSA over a decade ago, and while I don’t know of anyone factoring a key of that size, it’s within the realm of possibility for a government or other organization with a large number of computers.

Is it? How do I verify such claim?

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> Just a few days ago, someone factored the 862-bit RSA-260 key from the RSA factoring challenge.

Yeah, but how much time it required? and what about the resources? It is just a number, it is not all the 861 bits n numbers.

This article from 2000 is about estimating what would be required to factor 1024 bit RSA:

A Cost-Based Security Analysis of Symmetric and Asymmetric Key Lengths https://cr.yp.to/bib/2000/silverman.pdf

It was a response to the idea that 1024 bit RSA was under threat at the time.