Security will be a major issue but no more of an issue than for electronic banking.
Are you kidding ?
In "electronic banking" there is almost no way anyone can steal significant amount of money without being caught and the money recovered.
I agree with ghdp.
I was at a $20 bn boutique fund the other day talking BTC with the owners -- I looked around the office and noted that there really isn't anything anyone could steal. If a criminal walked in you could give him free reign -- what could he take? Client lists?
If he was REALLY clever he could figure out where to wore money....then what? He'd need to have a wire to a bank where he could wore it to
Found a case where bank security failed destroying a California escrow company.