Bitcoin's blockchain stores more than just Bitcoin transactions: it also contains a number of files and non-financial data. In a German paper, A Quantitative Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin, researchers from RWTH Aachen University revealed that someone had used the blockchain to store malicious content including child pornography.
In the study, researchers said, "Since all blockchain data is downloaded and persistently stored by users, they are liable for any objectionable content added to the blockchain by others." The paper warns that anyone using the blockchain could unknowingly and unintentionally be participating in crime. Researchers wrote, "Our analysis shows that certain content, e.g., illegal pornography, can render the mere possession of a blockchain illegal."
The study discovered 274 links to material related to child abuse in the files. In the open-source blockchain, they reportedly found eight files with sexually explicit content, three of which contain material that is illegal in "almost all jurisdictions." Unfortunately, not much can be done at this point. Per Mashable, a solution is not as simple as just removing a block from the blockchain: the entire chain would unravel. From a financial perspective, this feature is beneficial: it ensures that you do not double-spend your money. However, it becomes a problem when an illegal file is involved.
Despite the fact that the blockchain has hundreds of links to child pornography, Bitcoin's price reached over $9,000 on Tuesday for the first time in a week according to Fortune.