In May 2016 I was fortunate to be able to attend most of a symposium
sponsored by the Computer and Telecommunications Science Board (CSTB)
of the National Academies that dealt with society's ability to change
out cryptographic algorithms in the networked infrastructure (think
public key cryptography (PKI)  here, which underpins all kinds of
fundamental technologies like SSL/TLS). This eye-opening and disturbing
(at least for me) discussion was largely driven by the potential
(though controversial and complicated)  not-too-distant emergence of
quantum computing, which might well put much of the current PKI at
risk, and the prospects for dealing with it. If this is not on your
radar screen for the 5-20 year future (and the big time range
uncertainty is part of the problem) it should be, in my opinion.

The report from this symposium has is now available. There's a free PDF
download. It's at

https://www.nap.edu/catalog/24636/cryptographic-agility-and-interoperability-proceedings-of-a-workshop

Background on the workshop is at

http://sites.nationalacademies.org/DEPS/CYBER/DEPS_171459


Clifford Lynch
Director, CNI