It sounds like Adept, their blockchain, will put checkpoints out there (to say, bitcoin's blockchain) and hope that that secures it enough.
At least to wherever they put a note out there as a checkpoint. That's an amusing thing to do, IBM could have an address out there on the blockchain and occasionally, say daily, sign a transaction that acts like a checkpoint for their own chain. The costs of that could be really low, say 0.0001 to 0.0005 bitcoin. Fund the original address with a bitcoin and you're rolling.
Then if Adept comes under heavy and obvious denial of service attack, then they could go back to a checkpoint. If Adept comes under slow and stealthy attack, there would be nowhere to checkpoint back to that would be reasonable and they'd have to start over.
Just use bitcoin and colored coins from the beginning and save yourselves the trouble guys
Depends on if there's more features here in Adept than it seems.