Blockchain is the cornerstone of the crypto-currency Bitcoin. According to researchers, users have managed to infiltrate child pornography content into the unalterable data collection. Your possessions could then be illegal almost worldwide.
Researchers have discovered in the Bitcoin Blockchain several illegal content that has been infiltrated by users and can not be deleted due to the functionality. As they explain in their paper (link below), the researchers at RWTH Aachen University and the Goethe University Frankfurt / Main have compiled various methods with which information chunks that are not directly related to transactions can be stored in the blockchain. Altogether, they found more than 1600 files, which were channeled into the Blockchain in this way: Among them are two link lists, which refer to child pornographic content, one is a picture that is even child pornography.
Their paper:
https://fc18.ifca.ai/preproceedings/6.pdf
The scientists are highlighting a well-known problem that could have massive consequences for the blockchain and bitcoin as a whole. In the blockchain all previous Bitcoin transactions are collected. In order to exclude manipulations, a subsequent change is not only not intended, but is actively prevented by the cryptographic process. Using various methods, users can, in addition to the transaction data, send information to the blockchain, for example as a comment. As early as 2014, jokers had inserted a virus signature via such a path, whereupon virus scanners deleted the entire blockchain. Bitcoin clients then re-downloaded the multiple gigabyte file until it was removed again.
As the authors explain, it is illegal in the majority of states to have child pornography content. But if they are not directly removable on the blockchain, this could jeopardize the entire cryptocurrency because it is necessary to download the complete database. Although there are no judgments, but judgments from Germany, the US and Britain suggested "that illegal content such as child pornography could make the possession of Blockchain illegal." In addition, the problem is not limited to Bitcoin, because other cryptocurrencies rely on the blockchain technique and are sometimes even more vulnerable when more information can be added to transactions.
translated from a german text written by Martin Holland (CT)