  Thanks to built-in immutability and persistence, the blockchain is often seen
as a promising technology to certify information. However, when the information
does not originate from the blockchain itself, its correctness cannot be taken
for granted. To address this limitation, blockchain oracles -- services that
validate external information before storing it in a blockchain -- were
introduced. In particular, when the validation cannot be automated, oracles
rely on humans that collaboratively cross-check external information. In this
paper, we present DeepThought, a distributed human-based oracle that combines
voting and reputation schemes. An empirical evaluation compares DeepThought
with a state-of-the-art solution and shows that our approach achieves greater
resistance to voters corruptions in different configurations.
