Encryption where your email address is your public key. A central authority hands out the matching unlock keys.
The idea: Normally you must fetch someone's public key before encrypting to them. With IBE, anyone can turn a string like an email address into a public key, using the authority's published parameters. The authority holds a master secret that turns any such string into the matching private key, and gives it to whoever proves they own the address. Pairings make this possible: the sender can combine the identity with the authority's public value in a way that only the matching private key undoes.
Why it matters: Avoids certificate hassles, but the authority could read everything.
On the map: Boneh-Franklin IBE, CP-ABE
In identity-based encryption your public key is simply your identity, such as an email address[1]. An authority holding a master key issues the matching decryption keys. Attribute-based encryption generalizes this: you can decrypt if your attributes satisfy a policy, like "doctor AND cardiology".
Both are built from pairings (Boneh-Franklin 2001, ciphertext-policy ABE 2007)[2, 3]. The authority can decrypt everything (key escrow), which limits where they fit. Used in some enterprise email encryption and access-control research.
If any of these breaks, this breaks too.
If this breaks, these break with it.
Nothing on the map depends on it: it is an end point, something people use directly.