Actually, that's what already happened. And now they're trying to do it again.

https://www.schneier.com/blog/archives/2019/07/attorney_gene...

Posted on July 24, 2019 by Bruce Schneier on Security> Yesterday, Attorney General William Barr gave a major speech on encryption policy -- what is commonly known as "going dark." Speaking at Fordham University in New York, he admitted that adding backdoors decreases security but that it is worth it.

https://news.ycombinator.com/item?id=19916938

In 1998, the EFF and John Gilmore published the book about "Deep Crack" called "Cracking DES: Secrets of Encryption Research, Wiretap Politics, and Chip Design". But at the time, it would have been illegal to publish the code on a web site, or include a CDROM with the book publishing the "Deep Crack" DES cracker source code and VHDL in digital form.

https://en.wikipedia.org/wiki/EFF_DES_cracker

https://www.foo.be/docs/eff-des-cracker/book/crackingdessecr...

>"We would like to publish this book in the same form, but we can't yet, until our court case succeeds in having this research censorship law overturned. Publishing a paper book's exact same information electronically is seriously illegal in the United States, if it contains cryptographic software. Even communicating it privately to a friend or colleague, who happens to not live in the United States, is considered by the government to be illegal in electronic form."

So to get around the export control laws that prohibited international distribution of DES source code on digital media like CDROMS, but not in written books (thanks to the First Amendment and the Paper Publishing Exception), they developed a system for printing the code and data on paper with checksums, with scripts for scanning, calibrating, validating and correcting the text.

[...]

The exposition about US export control policies and the solution for working around them that they developed for the book was quite interesting -- I love John Gilmore's attitude, which still rings true today: "All too often, convincing Congress to violate the Constitution is like convincing a cat to follow a squeaking can opener, but that doesn't excuse the agencies for doing it."

https://dl.packetstormsecurity.net/cracked/des/cracking-des....

[...]

The US Department of Commerce has officially stated that publishing a World Wide Web page containing links to foreign locations which contain cryptographic software "is not an export that is subject to the Export Administration Regulations (EAR)."* This makes sense to us--a quick reductio ad absurdum shows that to make a ban on links effective, they would also have to ban the mere mention of foreign Universal Resource Locators. URLs are simple strings of characters, like http://www.eff.org; it's unlikely that any American court would uphold a ban on the mere naming of a location where some piece of information can be found.

Therefore, the Electronic Frontier Foundation is free to publish links to where electronic copies of this book might exist in free countries. If we ever find out about such an overseas electronic version, we will publish such a link to it from the page at http://www.eff.org/pub/Privacy/Crypto_misc/DESCracker/ .

* In the letter at http://samsara.law.cwru.edu/comp_law/jvd/pdj-bxa-gjs070397.h... , which is part of Professor Peter Junger's First Amendment lawsuit over the crypto export control regulations.