Does the 4-bit extraction code of Baidu network disk need to be encrypted and saved to the database?

I have made a function similar to Baidu"s network disk, and now there is a problem.
none of my 4-bit extraction codes are encrypted to the database.
if you are encrypting to a database, you need an algorithm that can be both encrypted and decrypted.
because when the user wants to know the password, I need to take the password out of the database, decrypt it, and send it to the front end.
which algorithm is better?

Mar.06,2021

did the landlord walk into any misunderstanding?

No matter how many bits the extraction code is, and what algorithm is used, it will be stored in the database and one-to-one correspondence between the network disk data and the data. It can also be publicly displayed to the data owner, and forwarded and shared by the owner.

in addition, when you enter the extraction code to extract the data of the network disk, as long as you go through the database query, you will download

.
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3024d-2bcd5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3024d-2bcd5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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