> ... splitting up encryption keys, a possibility floated by National Security Agency director Michael S. Rogers earlier this year. That would require companies to create a way to unlock encrypted content, but divide the key into several pieces — to be combined only under court order. Exactly how this would work remains unclear, but the memo warned that such a system would be “complex to implement and maintain.”

Actually, this is called a 'lawful escrow', and it is implemented in many enterprise PKI systems specifically to comply with court orders.

So I guess they decided to throw in one sane option, to offset three other fairly insane ones.