Sakai-Kasahara IBE

Public key cryptography (PKC) provides a very robust encryption in networking and electronic communication. The strength of PKC comes from the idea of paired keys that are independent (but mathematically dependent). The encryption-decryption process of PKC requires both parties of communication, i.e., sender and receiver, to provide each other with its public key and the digital certificate of authority, and each party has to keep a directory to store all parties’ public keys so these requirements are considered as drawbacks of PKC. To overcome these drawbacks, the identity-based encryption (IBE) came to existence. IBE is a form of PKC which uses a third-party server to distribute the public parameters to all the parties and extract the private key from the arbitrary public key. To encrypt the message, the sender will use the receiver public key, and to decrypt the message, the receiver will use the extracted private key. In this chapter, we discuss the Sakai-Kasahara IBE and how it differs from other IBE schemes. The additive, multiplicative, and full schemes of IBE are explained along with the encryption and decryption process. The security of this scheme is also discussed and proved.