An Implementation of the puncturable forward-secret key encapsulation from [GHJL17].
[GHJL17] Felix Günther, Britta Hale, Tibor Jager, and Sebastian Lauer. 0-RTT Key Exchange with Full Forward Secrecy. Cryptology ePrint Archive, Report 2017/223, 2017. https://ia.cr/2017/223.