Data encryption
First Synopsis
In the open correspondence and in the computer system, builds the safe reliable electronic commerce platform is very important. Usually needs through the encryption method to the customer related information, like the password, the contract and so on to protect, causes it not to steal or the distortion. When the customer hands in the service application, must to the customer status validity, the text integrity carry on the confirmation.
HMAC (Keyed-Hashing for Message Authentication) is a public agreement. It is one kind based on key's text complete proof technique, its security is the establishment in the Hash algorithm foundation. It requests the correspondence both sides shared system key, the agreement algorithm, to carry on the Hash operation to the text, like MD5, SHA, RIPEMD and so on, form the fixed length the authentication code. Correspondence both sides determine the text through the authentication code's verification the validity. This agreement may use for to make the encryption, the

數(shù) 據(jù) 加 密
一 簡介
在開放的通信和計算機系統(tǒng)中，建立安全可靠的電子商務(wù)平臺是十分重要的。通常需要通過加密的方法對客戶的有關(guān)信息，如密碼、合同等加以保護，使之不被盜取或篡改。當客戶提出服務(wù)申請時，必須對客戶身份的合法性、報文的完整性進行確認。
HMAC（Keyed-Hashing for Message Authentication）是一個公開的協(xié)議。它是一種基于密鑰的報文完整性的驗證方法，其安全性是建立在Hash算法基礎(chǔ)上的。它要求通信雙方共享密鑰、約定算法、對報文進行Hash運算，如MD5、SHA、RIPEMD等，形成固定長度的認證碼。通信雙方通過認證碼的校驗來確定報文的合法性。這個協(xié)議可以用來作加密、數(shù)字簽名、報文驗證等。HMAC可以與任何迭代散列函數(shù)捆綁使用。MD5和SHA—1就是這種散列函數(shù)。
這種結(jié)構(gòu)的主要作用是：
1. 不用修改就可以使用適合的散列函數(shù)。而且散列函數(shù)在軟件方面表現(xiàn)的很好。且源碼是公開和通用的。
2. 可以保持散列函數(shù)原有的性能而不致使其退化。
3. 可以使得基于合理的關(guān)于底層散列函數(shù)假設(shè)的消息鑒別機制的加密強度分析。