What it is
DISCLAIMER: The Plugin API is proprietary and your application should NOT use this API if you want a generic solution that will work with PKI clients from other vendors.
The plugin is an ActiveX-control and an NPAPI-plugin. The plugin interface in Net iD Enterprise was created like 20 years ago to provide cryptographic access (via NPAPI and ActiveX) in all web browsers to enable creation of digital signatures and write operation to smart cards and other hardware tokens. The plugin have served us well until Google, Apple, Mozilla and Microsoft decided to get rid of both NPAPI and ActiveX. The process started with Googles announcement in 2013. We got some more details in 2014 and in April 2015 NPAPI support was disabled by default in Chrome. With Chrome 45 in September 2015 the NPAPI support was removed. Mozilla removed NPAPI with Firefox xxxx while Apple had support until Safari 12 was released.
Remember that the world has not yet seen built in support for creation of digital signatures and/or write operations to smart cards and other hardware tokens.
But we have for sure seen lot's of different types on add-ons; NPAPI, ActiveX and local proxys. Even Microsoft maintained it's own ActiveX-component called "CAPICOM".
How it works