Update readme

README.md

@@ -10,3 +10,12 @@
 <!-- [![NPM](https://nodei.co/npm/@transmute/hpke.png?mini=true)](https://npmjs.org/package/@transmute/hpke) -->
 
 🚧 Experimental 🔥
+
+This is yet another HPKE implementation for JOSE and COSE.
+
+The purpose of this experimental implementation is to address open questions regarding the IETF drafts.
+
+- Party U / Party V - identity information in key establishment.
+- Integrated Encryption - how is it signaled in JOSE and COSE, what values are used for "alg" and "enc".
+- Cross Mode Attacks - How are they mitigated in COSE and JOSE?
+