$td = mcrypt_module_open( MCRYPT_3DES,”, MCRYPT_MODE_CBC,”); It is him who reported the error.

I searched a lot of solutions, the correct method should be (only for windows system):

This error occurs when the function mcrypt_module_open is used for decryption when the server running php lacks libmcrypt.dll.
Do the following settings on the server to solve the problem.

Download a php mcrypt module installation package from the Internet, you only need the libmcrypt.dll file (generally downloaded from the official website, there is already in the php directory)

1. Copy libmcrypt.dll to the system32 directory or the extensions directory under the php installation directory
2. Copy libmcrypt.dll to the bin directory of the apache installation directory
3. Find the php.ini file in the windows directory and open it
4. Find; Directory in which the loadable extensions (modules) reside.
extension_dir = “./”  such as: extension_dir = “D:\php5\ext”
these two lines, make sure that libmcrypt.dll can be found in the directory pointed to by extension_dir, or the system There is libmcrypt.dll under path
5. Find; under the Windows Extensions item; extension=php_mcrypt.dll this line and ;extension=php_iconv.dll (mine is not, omitted) these two lines, remove the front semicolon