1. It was possible to change the id in a URL and see another users encrypted key. That is now fixed.
By "encrypted key" you mean the encrypted password which is used to log into one's account? If so, were usernames leaked as well?
I mean a bitcoin private key encrypted in AES 256. The AES 256 encryption is performed on the client side (javascript) using a password the user supplies. I never see that password.
So basically in StrongCoin when a private key is created, it is create in the browser. The user supplies a password to the Javascript and then Javascript AES encrypts the private key before sending it to the server.
So we only have AES encrypted private keys and a clue field. The user could supply a clue to help them remember the password. Some users may have given too much information in the clue field.
The AES encrypted key (still protected) was leaked along with the clue field.
The clue field has now been removed from Strongcoin and a warning added to encourage users to create more secure passwords.