There is lots of information out there on how to get and install a free email certificate, but here it is again condensed and step-by-step. When complete, you’ll be able to sign and encrypt email messages with others who are making use of personal certificates.
Get a free certificate:
- Find a free certificate provider, such as InstantSSL/Comodo. A list of others is available here.
- Complete the form, recieve email confirmation.
- Open the link in the email with Firefox, you should see an alert about certificate installed.
Export certificate to a file:
- In Firefox, go to Preferences -> Advanced -> Encryption and push View Certificates.
- Click Your Certificates, click on the certificate (line with a serial number).
- Click Backup, select Desktop, and enter a password.
Import certificate to your keychain:
- On your desktop, you should have something like comodo.p12, double click it.
- Enter the password you just set and import the certificate.
- Save your exported certifcate somewhere for backup, remember your password.
Using your certificate:
- Quit Mail.app if it’s running, open Mail.app.
- Compose a new message, notice two new buttons (a lock and a check).
- When the check box is checked, your public certificate will be sent to the recipient.
- Once your recipient has your public certificate, you can sign and encrypt (lock button) messages.
- Any time you sign a message (check button checked), you are sending your public certificate.
Using your certificate with iOS devices:
- Check out this very good blog post.