Identity based cryptosystems

I did a quick reading on "identity-based" cryptography. The idea was firstly proposed by Shamir in 1994: "Identity based cryptosystems and signituare schemes".
The idea is to get rid of public key exchange protocols, third trusted parties, CAs in an assymetric (public/private) key cryptosystem by using the pre-known id of the users (like email address, social number, etc.) as their public key.
Shamir only addressed the implemetation of an identity-based signature scheme and conjectured that it is possible to make identity-based cryptosystems as well. Later, in 2001, Boneh proposed such a cryptosystem.