Some blockchains allow to embed arbitrary data in it.

What happens if someone embeds some illegal data, for example, a copyright-protected movie, or a collection of illegal pornography, inside a block?

Imagine, that it was found several years later. Can court declare distribution of offending block illegal, basically forcing a fork and erasing those several years of transactions from history (since that block is nessesary to validate them)? Will people who continue to use original chain (and dustribute original block with illegal data) be held liable for distribution of illegal content?

  • 1
    What do you mean by "declared illegal"? By whom?
    – user6726
    Commented Feb 28, 2023 at 16:41
  • 1
    anything that isn't protected by over-riding requirements (Constitutions, treaties, etc.) can be declared illegal.
    – Tiger Guy
    Commented Feb 28, 2023 at 17:19
  • That still doesn't say what it even means to be "declared illegal". The author needs to clarify.
    – user6726
    Commented Feb 28, 2023 at 17:28
  • @TigerGuy but only if pursuant to an enumerated power of said government. Governments can't legislate against activities that have no bearing on an enumerated power of government. For example, a government that has not been delegated powers to control fine-grained aspects of economy can't decree that all bakers shall make strawberry cupcakes. There must be an actual justification for such an edict within its Constitution.
    – pygosceles
    Commented Feb 28, 2023 at 18:40

1 Answer 1


It’s already is illegal

At least, possession of child pornography is. It doesn’t matter if it’s a physical photo, a stand-alone file, or embedded in a larger file like a block chain.

In general, ignorance that you possess the material might protect the first few people to be charged. However, once it became widely known that the material was in the blockchain, that defence will not be available to anyone continuing to host it.

  • Wouldn't that effectively mean that pretty much anybody could arbitrarily shut down a blockchain by just uploading such data and then publicly announcing (and showing) that they did so a few months later? Why has nobody tried that yet?
    – DLCom
    Commented Apr 10, 2023 at 13:43

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