一个单方加密-多方解密的公钥加密方案的分析

Analysis of a one-encryption and multi-decryption public key encryption scheme

在利用门限秘密共享方案构造的单方加密-多方解密的公钥加密方案中,发送者有唯一的加密密钥,不同解密者有不同解密密钥。密文可以被任一解密密钥得到同一明文,即多个接收者均可解密该密文,因此此类方案适用于广播/组播和会议密钥的安全分发等场景。庞辽军等人提出了一个单方加密-多方解密的公钥加密方案,并称其具备前向保密性。通过对其方案进行具体分析,表明其并不能满足前向保密性。

In an one-eneryption and multi-decryptiou public key encryption scheme constructed based on threshold secret sharing, the sender has a unique encryption key while each recipients has a distinct deeryption key. A ciphertext can be decrypted to the same plaintext by any decryption key. That is to say, multiple recipients can decrypt this ciphertext. Therefore, this kind of scheme can be applied in some situations such as broadcast/multicast and secure distribution of session keys. Pang Liaojun etal. proposed a one-encryption and muhi-deeryption public key eneryption scheme and claimed that their scheme meets forward secre- cy. However, by giving a concrete analysis, this paper indicates that their scheme does not meet forward secrecy.