如何实现云计算并在PHP中生成令牌？

Question

I wanted to do a cloud computing project in php. The project is that users will store their files in cloud server and if there is any manipulation in their files without their knowledge, then it should detect and correct it.. My question is that how can i implement this in php???

In base paper it is given that we should generate tokens for each file in server, and while detecting we can use that token to verify..

I didn't use socket programming.. Suggest me how to do pls...

Answer 1

The best way to know if a file as been modified or altered is to save a has copy of that file

$file = "name.pdf" ;
$md5 = md5_file($file);
$sha1 = sha1_file($file); 

Save a copy og each has in a database with the file name ... always check with the hash every time you need to verify or retrieve the file ... you would know if it has been illegally modified

Automatically correcting the file ... you can also save a backup copy on a CDN hosting and only retrieve it to replace the existing one if it has been modified or tampered with.

Another option is last modification date .. but that can be tricked ..

Let me know if this helps

Thanks :)