At this stage, we generally believe that there are two encryption methods, one-way encryption, and two-way encryption. Bidirectional encryption is the most commonly used in an encryption algorithm. It will directly understand the plaintext data that we can directly understand, and then, when needed, you can use a certain algorithm to decrypt these encryption. It can be understood in its original text. Two-way encryption is suitable for hidden communications, for example, when we shop online, we need to submit credit card passwords to the website. Of course, we don't want our data to be transferred directly on the web, because it is likely to be "sneakless" by other users, we I hope that our credit card password is after encryption, then transfer in network, so that after the website accepts our data, you can get an accurate credit card account by decrypting algorithm. The one-way encryption is just the opposite, and the data can only be encrypted, that is, there is no way to decrypt the data after encryption. Maybe we will think immediately, what is the use of such encryption? What is the effect of encryption algorithm that cannot decrypt? One application in the actual application is the user information encryption in the database, and when the user creates a new account or password, his information is not directly saved to the database, but after the encryption is reserved, so, even if this information is leaked, You cannot understand the true meaning of this information immediately. MD5 is an encryption algorithm using one-way encryption. For MD5, there are two characteristics that are important. The first is any two paragraphs, and the ciphertext after encryption cannot be the same; the second is any paragraph of plaintext data. After encryption, the result must always be constant. The former means that there is no other two paragraphs to get the same ciphertext, the latter means that if we encrypt specific data, the ciphertext obtained must be the same.
More knowledge, please see the MD5 algorithm special introduction
