ID-based encryption (or identity-based encryption (IBE)) is an important primitive of ID-based cryptography. As such it is a type of public-key encryption in which the public key of a user is some unique information about the identity of the user (e.g. a user's email address). This can use the text-value of the name or domain name as a key or the physical IP address it translates to.
The first implementation of an email-address based PKI was developed by Adi Shamir in 1984, which allowed users to verify digital signatures using only public information such as the user's identifier.
ID-based encryption was proposed by Adi Shamir in 1984. He was however only able to give an instantiation of identity-based signatures. Identity-based encryption remained an open problem for many years. One example of the research leading up to identity-based encryption is provided in Maurer.
The pairing-based Boneh–Franklin scheme and Cocks's encryption scheme based on quadratic residues both solved the IBE problem in 2001.