Disable the downvoting button. It's the only way to generate fair votes without downvote brigading. In case you are weak in logic: 0 (zero) becomes already negative if +1 (plus one) exists, therefore -1 (minus one) is a logic fallacy and was created by Reddit and YouTube only as censorship tool for downvote brigading unwanted posts. Ask.fm, Facebook, Twitter and Gab are working fine with only the upvoting button, which means downvote brigading doesn't exist there, while Reddit and YouTube are well known full of downvote brigading going on. Even if you will make votes public, then shills will still use alt accounts. Downvoting was deliberately invented by honeypot sites with the only purpose of censorship denying free speech.