移动社交网络中跨域代理重加密朋友发现隐私保护方案研究

Privacy preserving friend discovery cross domain scheme using re-encryption in mobile social networks

在移动社交网络中,为保证交友过程中的用户隐私,提出跨域环境下的代理重加密交友隐私保护方案。利用跨域多授权中心共享密钥,实现了跨域用户数据的互相访问与共享;利用代理重加密与属性加密技术,对用户属性密钥进行重新加密,实现了以扩充交友访问策略条件的交友匹配;利用用户隐私密文文件与密钥分离技术,增强了用户数据的隐私性。解决了现有方案中存在的用户数据不能跨域跨云共享、交友过少匹配及用户下线不能交友的问题。安全和实验分析表明,方案可以达到选择明文攻击(CPA,chosen plaintext attack)安全,保证交友用户的隐私不被泄露,并且比现有方案更有效。

In order to guarantee the users＇ privacy in the process of making friends in the mobile social networks, a new scheme of proxy re-encryption privacy protection in the cross-domain environment was introduced. The scheme employed the cross-domain multi-authority to sharing secret keys, so as to realize the access and shave of the cross-domain users data. And the secret keys of users＇ attributes were re-encrypted, based on the technology of the proxy re-encryption and attribute encryption, to achieve the friends matching under the conditions of extending the access policy. Meanwhile, in purpose of enhancing the privacy of users＇ data, the technology which contained the separation of users＇ privacy ciphertext and secret keys was adopted. Based on that, problems in the existing system such as user data＇s inability to be shared cross-cloud, less matching during the process of making friends and users＇ inability to make friends when offline had been addressed. Security and experimental analysis show that this scheme can achieve chosen plaintext attack（CPA） security, ensure the privacy of friend discovery, and that is more effective than existing solutions.