Actually, despite the BBC's twaddle, encryption is largley irrelevant in this scenario.
In the case of an organisation with fundamentally insecure IT, encryption confers no benefit at all as the encryption keys (/passwords) themselves must be assumed to be compromised in any attack.
I'm certainly not defending TT. They are, to me, in personal opinion, the root of much evil. But I might, just might, be tempted to have a flutter on their shares on Monday morning, as I suspect they are now on course for financial success.
I ought to stress, despite the fact I have no idea whether I am required to do so... I am most certainly not qualified to give financial advice and do not (yet) have any interest in companies concerned.