[v1k1nG]

There are many ways you could do that, like

PHP Code:

new IsRconAuthorized[MAX_PLAYERS];
CMD:rconauthorize(playerid, params[]){
    // password check, or whatever
    IsRconAuthorized[playerid] = true; // if player passes the checks
    return 1;
}
public OnRconLoginAttempt(ip[], password[], success){
    if(IsRconAuthorized[playerid] == false)return 1; // return whatever you prefer
    // code
    return 1;   
}