A New ID-based Multi-Recipient Public-key Encryption Scheme

Multi-recipient public-key encryption can be used to solve the security issue of One-To-Many communications such as secure broadcast. In a multi-recipient public-key encryption scheme, a ciphertext generated by the sender with its private key can be decrypted correctly by each recipient with its own private key. To solve the key negotiation problem between the sender and each recipient, the ID-based multi-recipient encryption has been proposed recently. Baek at al. proposed a general method to design an ID-based multi-recipient public-key encryption scheme with the IND-CCA2 security by using REACT, and at the same time, they proposed an excellent scheme. However, analyses show that there are still some flaws in their scheme, such as exposing recipient identity and unfair encryption. Motivated by these concerns, we propose a new ID-based multi-recipient public-key encryption scheme based on the same design method. Analyses show that our proposal can overcome all the flaws in Baek at al.'s scheme and is more practical in applications.