ENiGMA½ uses an Access Condition System (ACS) that is both familiar to oldschool BBS operators and has it's own style. With ACS, SysOp's are able to control access to various areas of the system based on various conditions such as group membership, connection type, etc. Various touch points in the system are configured to allow for `acs` checks. In some cases ACS is a simple boolean check while others (via ACS blocks) allow to define what conditions must be true for certain _rights_ such as `read` and `write` (though others exist as well).
\* Many more ACS codes are planned for the near future.
## ACS Strings
ACS strings are one or more ACS codes in addition to some basic language semantics.
The following logical operators are supported:
*`!` NOT
*`|` OR
*`&` AND (this is the default)
ENiGMA½ also supports groupings using `(` and `)`. Lastly, some ACS codes allow for lists of acceptable values using `[` and `]` — for example, `GM[users,sysops]`.
Some areas of the system require more than a single ACS string. In these situations an *ACS block* is used to allow for finer grain control. As an example, consider the following file area `acs` block:
```hjson
acs: {
read: GM[users]
write: GM[sysops,co-ops]
download: GM[elite-users]
}
```
All `users` can read (see) the area, `sysops` and `co-ops` can write (upload), and only members of the `elite-users` group can download.
