Question: Where can one find information on which areas of mathematics
are represented at which of the more than 20 universities in the
Democratic People's Republic of Korea (DPRK), and on which mathematicians
are working there?
The DPRK is a country with a population of about 25 million people,
and it is industrialised to a degree which has permitted it to successfully
construct nuclear weapons and ICBM's. So one would expect that there are
a decent number of mathematicians working at its universities.
However as the country operates an intranet of its own, not much from there is visible from the open internet. — So in particular Google will not help much further here.
Also, most results by researchers from the DPRK are published only in
national journals, and mathematicians from the country cannot be found
in the Mathematics Genealogy Database. On the other hand, people in the DPRK who need the internet for their work
do have access, but with some sites blocked and email possibly monitored.
Edit: The possibly most interesting source available on the open internet I found so far is NKScholar. — But firstly articles posted on that site are paywalled with prices in local currency, and secondly the site is Korean-language only — so I can't tell how much one can really find there. Maybe someone else can tell more.
Added on Jan 22, 2019: As to the publications from the DPRK which have
appeared in international journals: there are so far 118 articles with at
least one author based in the DPRK which have reviews in MathSciNet.
Of these, 101 are from the year 2012 or later. The articles touch 34
two-digit MSC numbers, and have been written by more than 100 distinct
authors (where the exact number of the latter is not easy to determine due
to slightly varying romanizations of names etc.) based at about 20 distinct
institutions, mostly located in Pyongyang, the capital of the country.
Among these articles, 41 have been co-authored with colleagues from China,
9 have been co-authored with colleagues from Germany and 4 have been
co-authored with colleagues from other countries.
The areas represented best are MSC 35: Partial differential equations
and MSC 76: Fluid mechanics (together 47 papers)
— but also e.g. MSC 11: Number theory, MSC 16: Associative
rings and algebras, MSC 26: Real functions, MSC 37: Dynamical systems
and ergodic theory, MSC 53: Differential geometry, MSC 54: General
Topology and MSC 55: Algebraic topology are represented with several
papers, each. Given that there are almost as many distinct authors as
there are papers, given the breadth of the areas covered and given that
it doesn't seem likely that the country's mathematicians have started to
work all of a sudden barely a decade ago, what is visible in MathSciNet
seems merely like the tip of an iceberg to me — which emphasizes the
question about the "rest".
Best Answer
Here are some articles on cryptography. (I do not claim the veracity of them, as there is a lot of misinformation.)