Type of encryption and its related algorithm--one-way encryption

In the previous section, we discussed that symmetric encryption can solve the problem of communication confidentiality, but it cannot guarantee the integrity of the information.

Then we introduce an algorithm-one-way encryption. One-way encryption, like human fingerprints, is unique.

A to B when the information will be appended to the end of the one-way encryption results, B received later with the same one-way encryption algorithm, the calculation of the results of encryption and pass over the password comparison. If consistent, the information is complete.

So what are the characteristics of one-way encryption?

1, the input of the same, the calculation results must be the same

2, avalanche effect, a little bit different, it will lead to a completely different calculation results

3, fixed-length output, regardless of the original information size, the output of the result length must be consistent

4, irreversible, can not be calculated by the results of the original information (in fact, fixed-length output can be known as "irreversible")

For example:

Seems to address the integrity of the information. But the problem came again , E this third party intercepted a sent to B information, the information in the change and use one-way encryption to recalculate the information, the information sent to the b,b will be obtained by a one-way encryption algorithm results and the results of the transmission of the same, b that the information is complete.

This is still not to achieve the security of information, what to do next?

Someone would say, A and b negotiate a password. is the password transmitted over the Internet? Will it be heard by the warden?

If you want to know how to solve this problem, please listen to tell. ^_^

Type of encryption and its related algorithm--one-way encryption