For example , you might consider using certificate - based public private key pairs , or use an approach where two parties use a key agreement protocol diffie - hellman algorithm to generate identical secret keys for encryption without ever having to transmit the secret key 例如，可以考虑使用基于证书的公钥/私钥对，或使用以下方法：双方使用密钥一致协议（ diffie - hellman算法）生成相同的加密密钥，从而无需传输密钥。
The initialisation key is the first security gate in bluetooth security system , if the initialisation key is got by attacker , the attacker will get the common link key by continue listening the communication . if the common link key is known by others , the two device is no secret before he . the third party can not only listen the two device ' s communication but also assert him one party to authenticate the other . pairing at place where less people here will reduce the attack . to use long pin managed by diffie - hellman key exchange algorithm will also reduce the attack 初始字是蓝牙安全系统的第一道安全屏障，如果初始字被攻击者得到，攻击者就可以通过监听两设备的后续通讯进而获得两设备的公共链路字，如果两设备的公共链路字为第三方知晓，那么两设备对于第三方面而言就毫无安全性可言。第三方不但可以偷听两设备的加密通讯，还可以冒充其中一方向另一方鉴权。
Since whitfield diffie and martin e . hellman firstly brought forward public key cryptography in their new direction in gryptography in 1976 , public key cryptography has developed rapidly and so has public key infrastructure . in today ' s pki framework , public keys are maintained by ca through issuing digital certificate while private keys are maintained by key escrow agent 自从1976年whitfielddiffie和martine . hellman在《加密的新方向》一文中最早提出公开密钥密码术以来，公开密钥密码术如今已经得到了广泛的应用，而与之紧密相关的公钥基础设施( publickeyinfrastructure ， pki )也得到了很大的发展。
Then we do some research about the basic protocols , the elliptic curve diffie - hellman protocol is improved as it can ’ t make identity authentity and can ’ t resist third party ’ s attacks ; at the same time , the signature equation of elliptic curve digital signature algorithm is reconstructed , and the improved kp + lqalgorithm is applied into verification stage , the whole speech of the protocol is improved greatly 接着,研究和分析了基于ecc的各类密码协议。针对密钥交换协议不能进行身份鉴别以及存在第三方攻击的问题,对其加以改进;同时,对数字签名协议中的签名方程重新构造,并将优化的kp + lq算法用于验证过程,提高了协议的执行效率。
The scheme is more efficient than the basic cramer - shoup ' s encryption scheme while its security against adaptive chosen cipher - text attack can be proved under the hardness assumption of decisional difhe - hellman problem . 2 . study existing digital signature and develop an efficient digital signature based on certificate data 在分析基本数字签名方法的基础上，设计并实现了基于离散对数困难问题( dlp ) ，辅以hash函数和公钥证书进行签名和验证签名的数字签名方法。
We studied in detail the diffie - hellman share secret protocol and present an improved scheme of this protocol which could resist middle - insert - attack effectively . at last , based on the theory discussed above , we present a quadratic authentication ancl encryption system which could complete encryption / decyption , identify authentication and signature functions and integrated these functions in one smart card 在本课题中还对rsa公钥密码体制及数字签名技术进行了深入的研究，对目前网上安全协议中应用较多的diifie ? heliman密钥交换协议进行了深入研究，并对此协议提出一种基于rsa签名认证的改进方案，此种方法可以有效抵抗中间插入攻击。
In the research of secure communication , the thesis analyzes some shortcomings of diffie - hellman ' s crypt key exchanging protocol , presenting a new exchanging method based on the " station to station " protocol and cookie mechanism , realizing the software of crypt key exchanging and secure communication of ip datagram on router 在对安全通信的研究中，本文分析了diffie - hellman密钥交换协议中易受攻击的地方，提出了基于端对端协议及cookie机制的密钥交换新方法，并在路由器上实现了密钥交换和ip报文的安全通信。
Signature and verification systems , such as ecdsa etc , the discuss about key exchange systems such as deffie - hellman systeme , etc . this thesis also discussed several applications and information safety products of the elliptic curve cryptosystems at the finite field too , such as digital signature , the group signature , the application in the smart card Ecdsa等签名验证体制的选取， deffie - hellman等密钥交换体制的研究。论文也讨论了基于有限域上椭圆曲线公钥密码系统的若干应用和信息安全产品，如数字签名，组签名，在智能卡中的应用。
Some related key problems are also studied . firstly , the thesis analyses the gdh . 2 ( group diffie - hellman ) protocol , and points out its deficiencies , then discusses an extended contributory conference key agreement protocol - - mgdh . 2 proposed by the researchers at the institute of mobile communication in southwest jiaotong university 本文首先对m . steiner等提出的扩展的diffie - hellman协议( gdh . 2 )进行分析，指出了它存在的一些安全隐患，并针对其漏洞讨论了一个由西南交通大学移动通信研究所的研究人员提出的改进“协商式”会议密钥分配协议- - m - gdh . 2协议。
