I don't think there is a default password. The first time I connected to my workplace network which uses 802.1x authentication it prompted me to create a new password for credential storage. At some point after that I made a change to the profile that caused it to prompt for the password which I had forgotten. I let it erase credential storage since it only contained the 1 certificate. When I reconnected it prompted for a new password and created a new certificate. Not sure what else uses it besides 802.1x but I don't think its a big deal.