一个CCA安全的基于身份的门限加密方案

提出一个非交互的基于身份的门限加密方案,该方案在随机预言器模型下可证明是CCA安全的.首先利用一个简单的提高安全性的方法,得到一个将一般的基于身份加密方案的安全性从CPA提高至CCA的通用方法,接着运用该转化方法,构造了一个CCA安全的基于身份的门限加密方案实例且密文的传输效率较之前的方法有大幅提高.

A CCA-Secure Identity-Based Threshold Encryption

In this paper, a non-interactive threshold encryption scheme has been presented based on identity in order to prove the scheme of CCA-secure in the random oracle model. First, a simple conversion has been used to get a general method which improves the security of an identity-based encryption from CPA to CCA, then in the method, a CCA-secure identity-based threshold encryption scheme has been constructed. In the existing literature, there are few CCA-secure threshold schemes, in order to improve the security from CPA to CCA, some approaches existing need to add an one-time signature additionally for each encryption and the length of transmitting ciphertext will be increased (ciphertext has two more parts:verification key and signature). However, in the construction of this paper, the transmission efficiency is at least twice than that of previous methods.