数据加密--------外文翻译.doc

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 keys 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 codes verification the validity. This agreement may use for to make the encryption, the digital signature, the text confirmation and so on. HMAC may with any iteration hashing function bundle use. MD5 and SHA-1 are this kind of hashing functions. This kind of structures leading role is: 1. Does not need the revision to be possible to use the suitable hashing function. Moreover the hashing function displays in the software aspect is very good. And the sound code is public and general. 2. Maintain the hashing function original performance, but does not cause its degeneration. 3. Cause reasonably based on about first floor hashing function supposition message discrimination mechanism encryption strength analysis. 4. When discovers either needs the operating speed is quicker or the safer hashing function, may very easy realize the first floor hashing function replace. [Annotation]: When comp book documents, MD5 and SHA-1 are use the most widespread encryption to use the hashing function. Second HMAC algorithm principles 2.1 HMAC