Researchers at RWTH Aachen University in Germany recently downloaded the entire Bitcoin blockchain and discovered it contains links to child pornography websites and a possible image of a “mildly nude” minor. They were investigating the blockchain’s non-financial data to uncover “objectionable” content but stumbled across the appalling surprise. The researchers provided their findings in a new paper during the Financial Cryptography and Data Security 2018 conference in late February.
At the time of the download, Bitcoin’s blockchain weighed at a hefty 122GB in size. The researchers concluded that only 1.4 percent of all blockchain transactions contain non-financial data, which consumes a mere 118.5MB of the entire blockchain volume. Even more, the transactions with data they could actually read weighed a mere 22.6MB. This is where they stumbled across the child pornography.
A blockchain typically records transactions using Bitcoins or other cryptocurrencies. It’s a decentralized ledger that keeps track of anonymous purchases between buyer and seller. It’s secure because the technology is based on cryptography, thus data can’t be modified or traced back to a specific individual.
But users can inject the blockchain with non-financial data by encoding that data as a standard transaction. Currently, there are four services that can inject non-financial data into the blockchain: CryptoGraffiti, Satoshi Uploaded, P2SH Injectors, and Apertus.
After their investigation, the researchers unearthed 274 links to child pornography sites. But the problem goes beyond child pornography: The blockchain can also be used to store pirated copyrighted content, malware, stolen personal data and/or images, leaked government information, and other “illegal and condemned” content.
The real kicker is how a blockchain works: Because it is decentralized, it relies on a network of millions of PCs scattered across the globe rather than one specific bank or government institution. Thus, given that anyone can inject the blockchain with non-financial data, controversial and possibly illegal content can be problematic for everyone maintaining the blockchain.
“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,” the paper states.
Because of a blockchain’s anonymous nature, countries will need to add this technology to their list of platforms that can’t post illegal content, such as filesharing networks, newsgroups, online storage, social networks, and so on. More specifically, they need to deem blockchain data illegal that can be converted to “visual representation of illegal content” by anyone with access to the blockchain.”A plethora of fundamentally different methods to store non-financial–potentially objectionable–content on the blockchain exists in Bitcoin. As of now, this can affect at least 112 countries in which possessing content such as child pornography is illegal. This especially endangers the multi-billion-dollar markets powering cryptocurrencies such as Bitcoin,” the paper adds.
Unfortunately, due to the cryptographic nature of the blockchain, methods to remove illegal content is unknown at the moment.
