1. "Computer data security" firstly belongs to the category of computing technology and computer technology, and its classification code in the abbreviation table of China Library Classification is TP2. Look up the TP category in the short table of China Library Classification -—TP309 security -TP309.2 computer data security, so the classification number of "computer data security" in China Library Classification is TP309.2, and when writing a paper, generally mark "China Library Classification Number" after "keywords". The writing method is: [CLC classification number ]: TP309.2 or CLC classification number: TP309.2. "China Library Classification Number" can be found in the reading room of the school library, and can also be found online.