Bot left unkind message on our digital façade: “FU”!

‘Creative’ Sybil attack on our Go platform: Hacker misused public game board to share a hostile message.

For the last two weeks, hundreds of people were playing the strategy game Go on the lit-up Museum façade in the city center of Graz, Austria. Every night, on average 50 people, split in two teams, play and earn PLAY tokens as a reward. Supported by a consensus algorithm, each team sets their stones in their quest for surrounding more territory than the opponent.

This consensus algorithm became the target of a hacker. They apparently created a number of identities/instances to influence the decision making in the network and took over the game board. Instead of applying the rules of the game, they placed the stones to form letters and leave a message: “FU”

We luckily monitored our system and saw what was going on. We did not appreciate nor approve of this message and decided to block the IP address sending us ‘love letters’. Nevertheless, we appreciate the hacker’s contribution in our attempt to educate people about blockchain in a playful manner.

This was not only an interesting demonstration of a ‘Sybil attack’, it was even a creative performance in the public space. This shows how the reputation of a peer-to-peer network can be subverted and compromised.

The same could have happened in a so-called 51% (or majority) attack, where a group of miners in a blockchain network takes over control by having more than 50% of a network’s computing power.

Read a little more technical details about this sybil attack.