Well, from what I know, the encryption can only be decrypted using a 'key' which is stored on the Securitykiss server and your computer. Any 3rd party would have to use
brute force in order to find out the key with which they can decrypt the encrypted communications.
Given that SecurityKiss are likely to have a very long and strong key (using a combination of letters, numbers, special characters, etc), it would take a very long time to decrypt it, we're talking weeks - months. And its quite possible that they change their keys every few weeks, so by the time the old key is about to be cracked, the process would have to be started all over again because they changed their key.
Also, they're using the blowfish algorithm for encrypting, which is apparently unbroken so far (i.e it cannot be cracked without the key).
I used to work for a guy who was a former employee of some US government agency, bugging buildings etc (I think it was the NSA.) He told me that even if I found a fool-proof way of encrypting my communications it is still possible to sit outside my house in a van with some device which listens to the electromagnetic patterns of my computer and recreate the image on my monitor.
I'm kind of skeptical about this. Computers don't have anything to do with electromagnetics..? They use plain old DC current as far as I know..