Looks like I misunderstood how the leak happened. I was thinking they infiltrated Gemalto's infrastructure and stole the signing key. But it looks like the keys

Looks like I misunderstood how the leak happened. I was thinking they infiltrated Gemalto's infrastructure and stole the signing key. But it looks like the keys (lots of them - one per SIM) were stolen while they were in transit, because of weak/no transmission security. Since I have no way of knowing if my personal SIM key was stolen, I'll have to wait until AT&T works their way through their existing stock of SIMs and then request a new one. And hopefully get one that wasn't exposed.