An Introduction to Identity-based Cryptography

One significant impediment to the widespread adoption of public-key cryptography is its dependence on a public-key infrastructure that is shared among its users. Before secure communications can take place, both sender and receiver must generate encryption and signature keypairs, submit certificate requests along with proof of identity to a Certificate Authority (CA), and receive CA-signed certificates, which they can then use to authenticate one another and exchange encrypted messages. This process can be both time-consuming and error-prone, and is especially prohibitive for novice computer users. Frequently, individuals who can already receive encrypted email are still unable to send secure messages to others due to lack of preparedness, limited interoperability, device limitations or lack of technical competence on the receiving end. Given the need to communicate and the complexity of PKI-based cryptography, correspondence that could benefit from additional security is frequently conducted in the clear. Identity-based cryptography (IBC) seeks to reduce these barriers by requiring no preparation on the part of the message recipient. Although it provides some advantages over PKI-based approaches, it is not without its drawbacks.