Certificate authorithy
A CA issues digital certificates that contain a public key and the identity of the owner. The matching private key is not made available publicly, but kept secret by the end user who generated the key pair. The certificate is also a confirmation or validation by the CA that the public key contained in the certificate belongs to the person, organization, server or other entity noted in the certificate. A CA's obligation in such schemes is to verify an applicant's credentials, so that users and relying parties can trust the information in the CA's certificates. CAs use a variety of standards and tests to do so. In essence, the Certificate Authority is responsible for saying "yes, this person is who they say they are, and we, the CA, verify that".
If the user trusts the CA and can verify the CA's signature, then he can also assume that a certain public key does indeed belong to whoever is identified in the certificate.
Do you want to download Applitron's CA so can do it on this link
If you want you can download Applitron's certificate ca.appli.se.
Save it in a place ypu could remember, maybe a simple place like c: \
On a windows computer, start the command prompt and run the command below in the folder where you loaded the certificate.
On a windows PC kan du installere certifikatet hvis du løser følgende kommando i cmd-vinduet.
CD to the folder where you saved the CA.
Certutil -addstore -user Root Applitron-CA-2007-2016.cer
Answer yes to the question if you trust Applitron Datasystem AB's certificate.