http://i3xi5qxvbrngh3g6o7czwjfxwjzigook7zxzjmgwg5b7xnjcn5hzciad.onion/proposals/331-res-tokens-for-anti-dos.html
We want unlinkability to be protected by
information theoretic security or random oracle, and not just
computational security. Small token size: The tokens will be transfered to the service through the
INTRODUCE1 cell which is not flexible and has only a limited amount of
space (about 200 bytes) REF_INTRO_SPACE .