Database sensitive field encryption upgrade process and problem solving

1. The technical manager/architect sorts out the systems that need to be upgraded at the same time (the remaining systems can be upgraded separately), including:
   1. Different systems using the same database (e.g. 2 systems for a store)
   2. There is a DTS relationship between databases
2. For systems that are upgraded at the same time, evaluate the time required for code upgrades and refresh data, and define a unified upgrade time point
3. The technical manager corresponding to each system sorts out the table fields that need to be encrypted and decrypted, and notifies the big data; the big data follows the encryption and decryption fields of the business system to upgrade, and aligns the schedule with the business system
4. The business system and big data establish a spare encrypted field, and flash the encrypted data into this field. Note that the length of the encrypted field will be significantly larger than the length of the original field, and the expansion of the field length needs to be considered. Database operation function reference:
   • Set the encryption method: SET block_encryption_mode = 'aes-256-cbc';(Run before the execution of the SQL script, specify the encryption method, session level, and execute before each use)
   • Encryption function:select TO_BASE64(AES_ENCRYPT('上海银行', 'uBdUx82vPHkDKb284d7NkjFoNcKWBuka', 'c558Gq0YQK2QUlMc')) from dual;
   • Decryption function:select AES_DECRYPT(FROM_BASE64('E5NoyWGQwnMlf1UAUO/Xow=='), 'uBdUx82vPHkDKb284d7NkjFoNcKWBuka', 'c558Gq0YQK2QUlMc') from dual;
   • Length calculation of the encrypted field: the encrypted length depends on the length of the original field, and can be calculated according to the designed length. For example: abcdabcdabcdabcdthe result after encryption is sogxg0B8ozqvB5zs/tkb5yH55ccNfEuvr1l/HNluPgk=, the length is 44.
   • Pay attention to the length of Chinese characters: under UTF-8 encoding, a Chinese character occupies 2-3 actual characters.
5. Upgrade the reserved time window of the day, refresh new data, and modify the field name. ( At present, after our internal discussion, we can only add new fields, transform the system, delete the old fields after publishing, and publish again
   )
6. If the length exceeds 255 after encryption upgrade:
   1. This field does not use an index, consider using Textor MediumTextto store.
   2. This field uses an index and will not be modified for now.