| 摘要 |
The present specification provides an encryption system and a method thereof based on properties of a cyphertext policy, being safe from a chosen cyphertext attack wherein the length of the cyphertext is a constant. For this, disclosed is the encryption system based on properties of the cyphertext policy according to an embodiment comprising: a system setup part for generating a master secret key and a public parameter of a system; a secret key generation part for generating the secret key for a system user based on the master secret key, the public parameter and a set of properties; a cyphertext generation part for a cyphertext generation key and the cyphertext based on the public parameter, the property set, a critical value related to the property set and a transmission object message; and a decryption part for decrypting the message based on the public parameter, the cyphertext and the secret key, wherein the length of the cyphertext is a constant. [Reference numerals] (110) System setup part;(120) Secret key generation part;(130) Cyphertext generation part;(140) Decryption part |
