This repository was taken down due to a DMCA request.
The copyright owners allege that this repository contained "Go code that implements a hack of the Readium LCP DRM", which is completely false: all I did was read the specification and follow it to the letter - the code never attempted to brute force the user key or include any secret/copyrighted material.
However, DMCA also includes a section (§1201) that prohibits "circumventing a
technological measure that effectively controls access to a copyrighted work".
Although there are plenty of legitimate use cases for lcp-decrypt (eg.
reading legally acquired ebooks on devices that don't support LCP), it falls in
that bucket.
I made lcp-decrypt public in the hope that it'd be useful to other people
like me, but I don't want to engage in a legal process in the US. My only
option therefore is to remove the code from GitHub.