http://keybase5btp2qikoau6u326pvotn47gb55mo6fjxxyxdoywiinomr5id.onion/blog/2014-10-08/the-horror-of-a-secure-golden-key
You'd pick your own password for when you needed your data, but the companies would also get one, of their choosing. With it, they could open any of your docs: your photos, your messages, your diary, whatever. The Post assumes that a “secure key” means hackers, foreign governments, and curious employees could never break into this system.