This script offers 0 security:
1) When a player types in their password to register and/or login, their password (like all commands) will be logged to console as well as logs

2) There is no hashing of passwords. Passwords are saved to file as non encrypted strings.

When writing a login system you need to actually use proper security measures.
If you dont know how to do that, you shouldn't be writing a login plugin/script.

Theres enough of these on the market, we don't need more.