To send a signed message, verify that the 'Signed' icon has a checkmark in it, and not an 'x'. If the 'Signed' icon does not appear, select Customize in the lower left of the message header and add the 'Lock' and 'Signed' icons. A 'Signed' icon, containing a checkmark, should be in the lower right of the message header to indicate that the message will be signed. If you have just installed your certificate on your Mac, close Mail and then restart it.Use these instructions to enable Apple Mail to use client certificates to digitally sign and encrypt email. Now you can transfer your encrypted certificate file to another computer using a USB key, email, or other file sharing method. You'll then be prompted for a 'login' keychain password, which is usually the same one you use to log into your computer. Give your exported item a strong passphrase.p12 and the file format must be 'Personal Information Exchange (.p12)'.

Select a location for export, such as your Desktop.

Right-click the certificate and select Export alternatively, from the File menu, select Export Items.

You may have more than one personal certificate select the one issued by 'XYZ Standard Assurance Client CA' with the latest expiration date.

Select the certificate associated with your name.

The right pane will list all of your installed certificates. In the 'Categories' section, select Certificates.Select the keychain where you installed your certificate this will usually be the login keychain.From the Applications folder, open the Utilities folder and then open Keychain Access.If you want your personal certificate on other computers or devices, you will need to export it. Note:Your certificate is only available on the computer and user account where you install it. The certificate is now available for Apple Mail, Outlook, and other applications that can use client certificates. The certificate will be installed on your Mac and will appear in the 'My Certificates' section of Keychain Access. OS X Keychain Access will prompt you for the certificate passphrase This it the password you created when exporting the certificate from the browser.Double-click the file downloaded or exported.This article will go into detail on how to install certificates on OS X Apple Mail/Outlook.

Import outlook identity mac