Why do we ask you to sign a message?
In order to be active as a cryptocompany, De Nederlandsche Bank (DNB) insists on additional verification measures. More information regarding the demanded measures can be found in the announcement by DNB. We have protested against these measures up until the very last moment, also because they are ineffective with regards to the goals they intend to accomplish. Unfortunately this was not succesful and as such we have to verify bitcoin addresses (whitelisting).
According to DNB it is possible to verify ownership of a wallet by signing a message.