Update 'README.md'

README.md

@@ -29,6 +29,7 @@ ___
 - [Formula for Primes](https://en.wikipedia.org/wiki/Formula_for_primes)
 - [Catalan Numbers](https://en.wikipedia.org/wiki/Catalan_number)
 - [Spinor](https://en.wikipedia.org/wiki/Spinor)
+- [Post-quantum cryptography](https://www.nature.com/articles/nature23461)
 
 
 ## [Mathematics and Theoretical Computer Science](mathematics.md)