根據 RSA 加密系統和小公鑰的動態放大技術，提出了一種面向不同組的用戶的廣播加密新方案。在新方案中，每個用戶都采用相同的小公鑰，利用它可同時對不同組的接收者進行廣播加密傳送消息。加密階段發送者根據接收用戶數計算安全的放大因子，然后引入隨機整數，將明文消息加密生成廣播傳送的密文。這樣不僅提高了RSA 的加密速度，而且可同時抵御低指數攻擊和重發攻擊，并實現對不同組的接收者進行廣播加密傳送消息。
關鍵詞：RSA；廣播加密；低指數攻擊；重發攻擊
Abstract: In this paper, a new broadcast encryption scheme of RSA oriented multi-recipient is
presented, according to the protocol of RSA and the enlarging the small public key technology. This protocol allows multi-recipient using the same public key, use it the sender can transmit the cryptograph to multi-recipient at once time by broadcast. During the process of encrypting, the sender calculates a number to enlarge the public key based the number of recipients and selects a random number, then encrypts the message to cryptograph which can be transmit by broadcast. Therefore, it can enhance the encryption speed of RSA while withstanding the low exponent attack and multi-sending attack. More important, this protocol is provided with the function of transmit message to multi-recipient by broadcast. So it can be use in many domain of information.
Key words: RSA; Broadcast encryption; low exponent attack; multi-sending attack