A Quantitative Analysis of the Impact of Arbitrary Blockchain Content on Bitcoin

Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10957)


Blockchains primarily enable credible accounting of digital events, e.g., money transfers in cryptocurrencies. However, beyond this original purpose, blockchains also irrevocably record arbitrary data, ranging from short messages to pictures. This does not come without risk for users as each participant has to locally replicate the complete blockchain, particularly including potentially harmful content. We provide the first systematic analysis of the benefits and threats of arbitrary blockchain content. Our analysis shows that certain content, e.g., illegal pornography, can render the mere possession of a blockchain illegal. Based on these insights, we conduct a thorough quantitative and qualitative analysis of unintended content on Bitcoin’s blockchain. Although most data originates from benign extensions to Bitcoin’s protocol, our analysis reveals more than 1600 files on the blockchain, over 99% of which are texts or images. Among these files there is clearly objectionable content such as links to child pornography, which is distributed to all Bitcoin participants. With our analysis, we thus highlight the importance for future blockchain designs to address the possibility of unintended data insertion and protect blockchain users accordingly.



This work has been funded by the German Federal Ministry of Education and Research (BMBF) under funding reference number 16KIS0443. The responsibility for the content of this publication lies with the authors.


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Copyright information

© International Financial Cryptography Association 2018

Authors and Affiliations

  1. 1.Communication and Distributed SystemsRWTH Aachen UniversityAachenGermany
  2. 2.Data Protection Research InstituteGoethe University FrankfurtFrankfurtGermany

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