Change your signing and encryption certificate or key

Your BlackBerry smartphone uses your certificate or PGP key to encrypt messages in the Sent Items folder and includes your encryption certificate or PGP public key in messages that you send so that recipients can encrypt their reply messages.
  1. On the home screen or in a folder, click the Options icon.
  2. Click Security > S/MIME or PGP.
  3. Change the Certificate fields or the Default Key field.
  4. Press the Menu key > Save.