The document describes Identity-Based Encryption (IBE), including the key algorithms involved: Setup, Extract, Encrypt, Decrypt. It explains that IBE allows encrypting messages for arbitrary string identities like email addresses, without needing a public key. The PKG runs Setup to generate parameters and a master key, and Extract to generate private keys from identities. Encrypt uses an identity and message to create a ciphertext, while Decrypt uses the private key to recover the message. Applications include key revocation and delegation. Security relies on bilinear pairings on elliptic curves.

2. Identity Based Encryption

19. Adding the points P and -P

20. Doubling the point P

29. Big Picture encryption Alice Bob y Bob , cert (y Bob , Bob) (a,b) = (…) (a,b)