Landing phpMyAdmin error 1698, landing failed

There is a blog in front of the introduction of Debain Configuration Web environment, when the reconfiguration of the landing phpmyadmin when the problem, using root, enter the settings of the MySQL password, always prompted error 1698, I tried the following methods have failed, Primarily for configuration config.inc.php configuration files:
1. Set cfg[′servers′][cfg[' Servers '][i][' allownopassword ' = true;//attempt null password login, unsuccessful
2. Set cfg[′servers′][cfg[' Servers '][i][' auth_type '] = ' cookie '; Cookie to config, see the data is to do so can not enter the password can be directly logged in, or failed, and the error is greater, When entering into the phpMyAdmin landing page, the error.
3. Use the MySQL command to set the root user's password in the user table, which theoretically works, but does not work.
Finally, set the plugin field in the user table to NULL to successfully resolve the problem. The specific orders are as follows:
sudo mysql-uroot
Use MySQL;
Update user set plugin= "where user= ' root ';
Flush privileges;
Exit
If you still can't log in at this time, you can restart the server.
To set the config.inc.php profile on the Web, set the cfg[′servers′][cfg[' Servers '][i][' user ' and cfg[′servers′][cfg[' Servers '][i][' Password '], but I can not find these two parameters in the file, this is still not clear, if there is any great God know, do not hesitate to enlighten, in the next not very grateful.