In recent months, Bitcoin’s supporters have pointed to its falling use in illegal transactions as a sign of the cryptocurrency’s growth toward mainstream acceptance. But German researchers say that links to child pornography within technology underlying Bitcoin could stifle its development.
Most of the content left on the blockchain has been relatively benign—tributes to the late Nelson Mandela, or messages to loved ones on Valentine’s Day. But the ones that could be illegal, containing links to child porn, for example, could be an outsized problem for the Bitcoin community.
The researchers said they found 1,600 instances in which transactions on the blockchain included non-financial information, representing about 1.4% of transactions. Since the Bitcoin blockchain is immutable, those who download it are also unwittingly downloading links to child porn.
It’s not the first time curious onlookers have found links to child pornography in Bitcoin’s blockchain. Users first pointed out the links in 2013. Despite this fact, it is perhaps the first time researchers have been able to quantify the volume of potentially illicit material hidden in the blockchain.