If you need to, open the Keychain utility in Mac OSX and export the certificate from Verisign (it wll end in .p12).
Email this certificate to yourself as an attachment and open that email on the iPad.
Press and hold the certficate to be taken to another screen where you will be asked if you want to import the certificate. Tap import and then whatever other passwords are wanted.
Go to Settings -> Mail, Contacts, Calendars -> (your email account) -> Account -> Advanced -> S/MIME
Turn S/MIME on.
Click Sign to turn it on and select the certificate.
Click Encrypt to turn it on and select the certificate.
When receiving email from someone else using S/MIME, unlike Mac OSX Mail, their certificate is not automatically saved. Instead, tap and hold their name and indicate in the following screen that you want to save their certificate.
Hope this helps. Peace.
James, I think I'm close here. I have successfully imported my S/MIME certificate and have turned on Signing and Encryption for testing purposes with my Ipad 2. When I send an encrypted email to myself from Thunderbird the message is automatically decrypted on my Laptop and my Ipad. Is this normal behavour?
I have not entered my passphrase for my SMIME certificate on either platform yet on Thunderbird I show the Padlock Icon and Envelope with the red stamp on it. When I click on the envelope within Thunderbird it says "This message was encrypted before it was sent to you". On the Ipad I see a padlock and a check mark next to my email address. When I click on my name it says "The sender encrypted this message and signed it with a trusted certificate.
So it appears everything is working, I just concerned that I'm not being prompted for my passphrase. Thanks for the tips above. I think the key "Press and hold the certficate to be taken to another screen where you will be asked if you want to import the certificate. Tap import and then whatever other passwords are wanted." I had to hold my finger on the certificate for about 5 seconds before the Ipad came up with the Import prompts.
What would be nice in the next version of Mail on the Ipad is to have an S/MIME button with a couple of options that allow you to turn on or off signing or encryption per message. Currently one has to go to the Settings tab outside of Mail to enable or disable the functions that one wants to have turned on.
Yes, it sounds like everything is working for you.
If you gave a certificate a password when you exported it, you need to supply that same password when you import it… but that's it. After that, everything works seamlessly (or should). The program uses the approprate certificate to decrypt or encrypt the message without any further work on your part.
Yes, it is unfortunate that one has to leave the Mail program and go to Settings just to turn off or on encryption for one message.