shared to the bitcoin-dev ML for initial discussion: https://groups.google.com/g/bitcoindev/c/nOZim6FbuF8/m/FUbFjHYZAgAJ

Hi Dathon Ohm,

I did a cursory review of your BIP proposal, not on the technical matter as there
is no reference implementation available, but I did one on the legalities raised
in the text (grep'ing the word "legal" one can find 15 references versus only 2
references to the word "technical").

Under European law, there is a clearly established line of jurisprudences exonerating
internet service providers or hosting operators to have to install a system for
filtering all electronic communications passing via its services which would
apply indiscriminately to all its users for any kind of content (CJUE, 24-11-2011,
aff C-70/10 Scarlet Extended SA c/ SABAM, CJUE, 16-02-2012, aff C-260/10 SABAM c/ Netlog).
Rather to engage in generic filtering on the burden of services providers, courts
have generally yielded decisions asking for fine-grained deletion of a specific content,
as a safeguard of other interest at stake, notably users's right to privacy [0].

Further, in the eventuality of an extended filtering system would have to be put
in place by a service provider, and if said filtering system design would be unable
to dissociate between legal content and illegal content, the introduction of this
filtering system would consistute an infringement of the freedom of expression and
information (CJUE, 26-04-2022, aff C‑401/19). Those judicial decisions are litteraly
encompassing peer-to-peer softwares in their scope, as somehow before Bitcoin, they
was something called Bittorent.

Moreover, this line of jurisprudence underlights that any interference with one's
fundamental right of expression should be lay down under clear and precise rules
governing the scope of the interference. This is not a mere formality, as again
and again too restrictives measures are strike down (CEDH, 02-02-2016, Index.hu/Hungary,
aff. n° 22947/13). As far as I know, I'm not aware of any European continental
country that has made a legislation on how one is allowed to use his right to
the freedom of expression in the context of publishing stuff in a Bitcoin block.

Under the US law, I won't risk making legal comment for now, as for anyone who is
following the work of the Electronic Frontier Foundation from times to times, there
is a pending case in front of the US Supreme Court, Cox Communications, Inc vs. Sony
Music Entertainment specifially on the liability of Internet service providers. But given
that US culturally are more protective of the freedom of expression, this would be an
even higher bar to restrain freedom of expression.

I concur with Gregory Maxwell. There is zero need to change the consensus rules.

In the idea one would like to limit one's responsbility arising from how bitcoin
consensus data can be encoded or decoded to "obviously" "illegal" content (as strictly
defined by a specific national legislation) [1], fuzzy encoders and decoders for
end-to-end or point-to-point communication could be formalized as BIP documents,
that would put an asymmetric cost on the decoders, with the upper bound being the
impossibility of decoding.

Fuzzy algorithms is not sci-fi tech it's actually what is used for Minisketch.

Best,
Antoine

[0] "Those addresses are protected personal data because they allow those users to be precisely identified"
[1] This is not a mere technicality, under information theory, one could come up with
a alphanumeric encoding algorithm that could certainly yield text-based religious blaspheme
in a lot of countries in the world from years-old un-reorgable historical blockchain data.
We're all used to "The Times 03 Jan..." in the genesis block, but it's just picking hex
as a decoding algorithm...