[curves] Improvements on discrete log for Koblitz curves?

[Trevor Perrin]

An eprint paper claims an improvement over Pollard Rho vs the FIPS
K-409 and K-571 curves:

https://eprint.iacr.org/2015/310.pdf


Seems like this might be building on the direction described below,
from the "ellipticnews" blog:

https://ellipticnews.wordpress.com/2012/05/16/two-new-papers-on-the-ecdlp-in-characteristic-2/


Anyone able to place the work in context?  (is this a real
improvement?  by how much?  what are prospects for further advances,
application to other curves, etc.)


Trevor