A team of researchers from the RWTH Aachen University in Germany found what seems to be illegal content on the blockchain while sifting through it to examine how much arbitrary data it contains. In their analysis, the team of German researchers uncovered about 1,600 inserted files, over 99% of them which are texts and images of an outlawed nature, including links to child pornography, copyright and privacy violations, and more.
"Since all blockchain data is downloaded and persistently stored by users, they are liable for any objectionable content added to the blockchain by others. Consequently, it would be illegal to participate in a blockchain-based [system] as soon as it contains illegal content."
This basically means that anyone who has downloaded data from the blockchain unknowingly participated in the distribution of child pornography, which is obviously very illegal.
Possession and/or distribution of such material is outlawed in 112 countries as per the 1989's Convention on the Rights of the Child, which makes the blockchain illegal as well due to its part in the process of child pornography distribution. We recently reported on a United States-wide ban on the Petro, a Venezuelan government-backed, cryptocurrency that could end up at additional damages due to it's connection to the government.
This news not only means that Bitcoin could be banned worldwide, it also means that any other cryptocurrency is at risk of its use being prohibited by governments as well as the United Nations.