Methods, components and systems for implementing secure and efficient broadcast encryption schemes with configurable and practical tradeoffs among a pre-broadcast transmission bandwidth t, a key storage cost k, and a key derivation cost c, in which the schemes use subtree difference and key decomposition to generate secondary keys, use the secondary keys to encrypt the broadcast and generate ciphertexts, and use the RSA encryption scheme to implement derivability between the primary keys and the secondary keys. To decrypt the broadcast, a privileged user uses one of its primary keys to derive a secondary key, which is used to decrypt the broadcast. The product of key derivation costc and the key storage cost k is at most (2a−log a−2)loga n, when n is the number of users, 1≦b≦log n, a=2b, and revoked users rn/3.
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机译：方法，组件和系统，用于在广播前的传输带宽t，密钥存储成本k和密钥派生成本c之间实现可配置和实际折衷的安全有效的广播加密方案，其中，方案使用子树差异和密钥分解要生成辅助密钥，请使用辅助密钥对广播进行加密并生成密文，并使用RSA加密方案来实现主密钥和辅助密钥之间的可导出性。为了解密广播，特权用户使用其主密钥之一来导出用于解密广播的辅助密钥。密钥导出成本c与密钥存储成本k的乘积最大为（2a-log a-2）log a n，当n为用户数时，1≤b≤logn，a = 2 b ，并撤消了用户r 展开▼
