Identity-Based Encryption
Identity-based encryption (IBE), proposed by Shamir and realized by Boneh-Franklin, uses the user’s identity string (e.g., an email address) as the public key, with private keys derived by the PKG.
Purpose
It removes public-key certificate distribution: the sender encrypts directly to the recipient’s identity, fitting environments without a PKI.
Mechanism
The PKG master key generates the system parameters and user private keys d_ID = H(ID)^s. Encryption uses the system parameters and ID; decryption uses d_ID. It builds on bilinear maps, with key escrow at the PKG.
Use cases
- Simplified email encryption
- Encryption without PKI infrastructure
- Identity-based signatures