A digital certificate is made up of two elements: the public key and the private key. The private key is the element that contains the specific information of the holder of each certificate, while the public key includes the generic information relating to the characteristics of the certificate.

To use a certificate for authentication, signing, etc., it is necessary to have the complete certificate (public key+private key). However, in some cases the public key may be needed, for example to check its validity .

Warning: never share the private key of your certificate . You can share the public key, for example to resolve an incident in the use of the certificate.

Below we explain how to obtain the public key of a digital certificate, depending on the browser where you have it installed (in the screenshots an idCAT Certificate is shown as an example of a software certificate):

Export the public key of a certificate installed in Google Chrome

Step 1: Go to the button from the top right. Option " Settings ">Privacy and Security>Security- Manage certificates .  

Step 2 : Select the certificate and click the "Export" button.

Select the export button

Step 3 : Select the option " Do not export the private key "

Select the Do not export private key optionSelect the form you want to use

Step 4: Finally, define the location and file name. You now have the certificate's public key exported.

Define the location and name of the file

Export the public key of a certificate installed in Keychain Access - Mac

Step 1 Go to Keychain Access > Login > My Certificates.

Step 2 Select the certificate we want to export, we will see that it shows us that it has a private key.

Step 3 Click the right mouse button on the private key of the certificate, a window with several options will open, we must select "Export".

Step. 4 A window will open where we will have to select the file format "certificate (.cer)" from the drop-down list, indicate the name of the public key and the location where we want to save it. Finally, we will click on Save.

We will now have the public key (.cer) of the certificate in the defined location.

Export the public key of a certificate installed in Microsoft Edge

Step 1: With the Microsoft Edge browser, go to the button in the upper right>Settings>Privacy, search and services tab>Security. At this point click on the "Manage Certificates" button and then the " Personal " tab.

Step 2: select the certificate and click the "Export" button.

Select your certificate and click Export.

Step 3 : Select the option " Do not export the private key "

Select the Do not export private key optionSelect the format you want to use

Step 4: Finally, define the location and file name. You now have the certificate's public key exported.

Select the location where you want to export it

Export the public key of a certificate installed in Firefox

Step 1 : Go to Tools >Settings>Privacy and Security > Show certificates

Select show certificates

Step 2 : Select the certificate and click the "View" button.

Press the view button, once the certificate is selected.

Step 3 : in the "Others" section, click on the "PEM(true)" option

Inside Others in the Download row press PEM (true)

This option will allow you to download the public key of your certificate in .pem format.

Step 4 : To change the format to .cer, you can rename the file (by right-clicking on the file and selecting the Rename option) and change the .pem extension to .cer.

Select Change Name with the right mouse button

when you press "enter" the file will be in .cer format

modified file with .cer format

You already have the public key of the certificate exported.