OPC technology is widely used in automation systems of various enterprises. Today, there are eight standards which are responsible for a certain set of functions. All of them were designed to improve the convenience of data exchange between devices by different manufacturers.
Currently, one of the most discussed issues is the safety of automated process control systems. The OPC Foundation organization is directly involved in its solution. It supports safe functioning and interaction between systems from several providers. This communication aspect is reflected in the specifications of OPC DA, OPC HDA, OPC AE, which are usually referred to simply as OPC Classic, as well as in the latest released version — OPC UA. Security categories include the following:
• data encryption,
• OPC Server and OPC Client identification,
• authentication and authorization,
• transmission of encrypted information.
OPC Classic specifications are based on COM/DCOM. This is one of the most common communication protocols. In this case, security is based on the rights granted to the user. Thus, OPC DA/HDA/AE standards rely on the security provided by communication protocols. There may be a number of difficulties in this regard. The above mentioned specifications are difficult to implement in systems involving several OC. To provide access to a particular operating system, you must have COM/DCOM.
This experience was taken into account in the development of OPC UA. Such problems do not arise with the latest version. This standard provides security at a higher level than data transmission. When working with OPC UA, there is no need to make changes to the applications every time. Even when new control protocols are added, full security is maintained.