http://i3xi5qxvbrngh3g6o7czwjfxwjzigook7zxzjmgwg5b7xnjcn5hzciad.onion/proposals/280-privcount-in-tor.html
For example: if the count document lists the keywords "b", "x", "g",
and "a" (in that order), and lists instances "0" and "2", then the
decrypted data will hold the blinding values in this order:
b, instance 0
b, instance 2
x, instance 0
x, instance 2
g, instance 0
g, instance 2
a, instance 0
a, instance 2
4.