Developer Reference Chart Purchasing and Licensing

User Permits

Each computer that runs applications that use ENCX is licensed using a hardware or software dongle. When you buy a standard ENCX licence, we supply you with a dongle.

Encoded on each dongle are codes called User Permits. There are two User Permits - one for ENC charts and one for ARCS charts.

We send you the User Permits in an email when you buy a dongle.

Chart Purchasing

To purchase commercial encrypted (S-63 ENC or ARCS) chart data you must use a chart agent. (If you only want to use unencrypted ENCs - e.g. NOAA - you might want to look at ENCX UDE)

Note: You can buy your charts from any chart agent but Chersoft are chart agents for the UKHO, so please ask us for a quote.

When you buy commercial chart data, you have to tell your chart agent what the ENC or ARCS User Permit from your ENCX dongle is.

The chart agent purchases chart permits for the charts your require from a chart supplier - either the UKHO (ENC or ARCS charts) or Primar (ENC charts).

The chart supplier creates chart permits which are tied to your User Permit such that together, they which allow you to install and decrypt the charts.

The chart supplier or agent sends you the charts (ENC or ARCS transmittal) and the chart permits. You install these using ENCX.


Hardware dongles are small USB devices similar in size to the "memory sticks" that many people use. You can move dongles around from computer to computer.

Our DFS implementation is a small file that contains the same information that we'd store on a hardware dongle. DFS files are normally encrypted so they can only be used on a particular machine.

Charts are licensed to a particular dongle. If you have a system where two computers are installed on one vessel the dongles can be identical "clones" of each other. That way you only pay one set of chart licensing fees. The second dongle may be used as a backup in the event of mechanical damage to the primary system.

AVCS and Primar licensing usually allow for up to 5 systems to share their licences on a single vessel/site, but there are exceptions to this.