How to make a backup of your electronic certificate

Windows - Copying the certificate in Internet Explorer

Access the certificate store from the "Tools" option in the Internet Explorer browser menu or from the icon located in the upper right corner of the browser window and go to "Internet Options".

Select the "Content" tab and click the "Certificates" button. The certificate should appear under the "Personal" tab.

To make a backup (export), select the certificate and press "Export...".

The "Export Wizard" will then open. Click "Next" and then check the "Export the private key" box (if you have just obtained the certificate and it cannot be checked, there may have been a problem with the download or installation; In this case, contact the entity that issued the certificate).

On the next screen, leave the default options checked, click "Next" and select a security entity or set a password to protect the private key. If you forget your password, there is no way to recover it. Click "Next".

Click "Browse" to choose the path where the certificate copy will be saved, set a name for the file, and click "Save," "Next," and then "Finish."

If everything went well, the message "Export was successful" will appear.

The icon for a valid copy will be an open envelope with a certificate sticking out and a key and the .pfx extension. If the extension is not displayed, right-click on the certificate icon and go to "Properties".

Failure to check the "Export private key" box would result in an invalid copy (the file would have the extension .cer and the icon would be a certificate without any key). The private key is the personal information that the certificate contains and without which signing is not possible.

If the copy were not valid, it would be installed in the "Other people" tab instead of the "Personal" tab and the certificate would not be valid to work on the AEAT page.

If at any time you need to reinstall (import) the certificate and you do not have a valid copy, you will need to request a new certificate.