//===== rAthena Documentation ================================
//= MD5 Hash Check
//===== By: ==================================================
//= rAthena Dev Team
//===== Current Version: =====================================
//= 20120921
//===== Description: =========================================
//= This file outlines the login server's MD5 hash check.
//============================================================

The login server is able to perform a check of the client's MD5 hash.
This will ensure that a user has not tampered with the client and that
the client is the one specific to your server.

The client can only send the correct MD5 hash to the server on certain
server types, so a client diff is required to ensure the hash is sent.
A link containing the required WeeDiffGen plugin can be found at:
http://rathena.org/board/topic/70841-r16771-client-md5-hash-check/

The settings for the hash check are located in conf\login_athena.conf:

// Client MD5 hash check
// If turned on, the login server will check if the client's hash matches
// the value below, and will not connect tampered clients.
// Note: see doc\md5_hashcheck.txt for more details.
client_hash_check: off

// Client MD5 hashes
// A player can login with a client hash at or below the account group_id.
// Format: group_id, hash
client_hash: 0, 113e195e6c051bb1cfb12a644bb084c5
client_hash: 99, cb1ea78023d337c38e8ba5124e2338ae

To enable MD5 hash checks, set 'client_hash_check' to 'on'.
The 'client_hash' group_id can be any of the groups in conf\groups.conf,
and is particularly useful if you wanted to allow GMs a different client
than normal players; for example, a GM client could be hexed differently
with dual-clienting enabled and chat flood disabled.