Thursday 31 August 2023

Bitcoin File Format

Does copyright subsist in the 'Bitcoin File Format'? This was the question in Wright & Ors v BTC Core & Ors [2023] EWHC 222 (Ch), where Mellor J found earlier this year that it did not because the subject-matter was "not expressed or fixed anywhere" (paragraph 62). On appeal ([2023] EWCA Civ 868), Arnold LJ decided that all that was required was that "the structure be completely and unambiguously recorded" (para 69). The claimants did therefore have a "real prospect of successfully establishing the fixation requirement is satisfied" and the appeal was allowed. Do the claimants now therefore have a prospect, real or otherwise, of establishing that this fixation requirement is satisfied?

Firstly, for those who may be unfamiliar with the term (which is possibly understandable since it appears to have been invented for the legal proceedings), what is the "Bitcoin File Format"? According to the claimants, it is "the original work consisting of the structure of each block of the Bitcoin Blockchain" (referring to a Schedule which is unfortunately not publicly available, but which was written in 2022). The Bitcoin File Format (BFF) is therefore the way that data is arranged in each Bitcoin block. The basics of this are explained on the Bitcoin Wiki page for the Genesis Block, which in raw hexadecimal form looks like this:

Genesis Block (annotated)

My annotations indicate the various parts of the block, which have a particular meaning when read by the Bitcoin software. There is therefore a clear format to the block, which is the same for every subsequent block, but importantly the format is not clear from the block itself. There is in fact no information in the block itself about what each section means. Instead, the meaning has to be inferred from software that knows what to look for. This makes the fixation of the format different to that in, for example, an XML template where the template contains a structure (in <brackets>) that indicates what the content is about. This allows an XML reader to extract information from a file created using that template and order it accordingly. Previous cases have found that copyright can subsist in XML templates, i.e. an XML file with just the placeholders and no content.
An example XML template (from here)

This was the difficulty that Mellor J had when assessing whether the claimants had established that there was a serious issue to be tried. If the claimants could not establish how the format itself (not simply the data output, which was inevitably different every time) was fixed, the fixation issue was not met and there was no serious issue to be tried. The judge attempted to get the claimants to file evidence showing how the fixation requirement was met. The claimants filed various explanations from themselves and third parties that showed how the structure of each block was defined, but none of this was found to be relevant because they were not relevant works identifying the structure, only things that were provided after the event. As Mellor J stated:
"It is most revealing that, despite all these opportunities, the Claimants have not filed any evidence to the effect that a block contains content indicating the structure, as opposed to simply reflecting it. By 'content indicating the structure', I mean, by way of a crude example, a flag or symbol in the block which signals 'this is the start of the header' or 'this is the end of the header', or an equivalent of the sort of content which is found in an XML file format. Whilst I entirely accept that each block conforms to the structure described in Schedule 2 to the Particulars of Claim and is an instance or manifestation of that structure, the absence of such evidence confirms my initial view that, whether one considers the point at which the first, second or subsequent block(s) were written embodying the structure of the file format, nowhere was the structure of Bitcoin File Format fixed in a copyright sense in a material form in any of those blocks" (paragraph 57).

This is the key point on which the judgment was overturned on appeal. It is indeed clear that the format of the block is not evident from the block itself, unless you know what you are looking for, but Arnold LJ considered that this did not actually matter. The block did have a format, but the fixation of this format did not need to be in the same place. He summarised the requirements that the claimant would need to meet in order to establish that copyright subsisted in the BFF, which were set out (in paragraph 61) that: 

i) the Bitcoin File Format is a work; 
ii) it is a work that falls within one of the categories of protectable work specified in the 1988 Act; 
iii) the work has been fixed; 
iv) the work is original; and 
v) the work qualifies for copyright protection under the 1988 Act.

The only point in contention was iii), which Mellor J found was not met. Arnold LJ considered that, while it was correct that the work, that is to say the structure, must be fixed in order for copyright to subsist in it, it did not necessarily follow that content defining the structure was required in order to fix it. All that is required is that the structure be completely and unambiguously recorded. The claimants did therefore have a real prospect of successfully establishing that the fixation requirement was satisfied, provided they were able to provide evidence of the structure being recorded from the right time, i.e. from before the alleged infringements. 

An odd feature of this case is that, in the original Particulars of Claim (PoC), the claimants alleged infringement of: i) Database Right in the Bitcoin Blockchain (discussed by me here); ii) Copyright in the Bitcoin File Format; and iii) Copyright in the Bitcoin White Paper. There was no mention of the Bitcoin software itself, which as it turns out is actually where the Bitcoin File Format is fixed. The structure of the Genesis Block, for example, is in fact completely defined in the original Bitcoin software. It therefore strikes me as strange that the claimants chose not to refer to this as providing the fixation requirement, particularly as Mr Wright claims to have written the software himself and would therefore presumably know where to look. Given that Arnold LJ has decided that the work and the fixation requirements can be met by different things, perhaps this will be what the claimants come up with next in their attempts to enforce copyright in the Bitcoin File Format. 


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