When Stephen King’s new horror-fiction novella, “Riding the Bullet,” was released in a wave of hype earlier this month, King himself was unable to read his own story in the downloadable format. Why? King is a Macintosh user, and the proprietary technology that enables users to read the story was available only on Intel-based PCs running the Windows operating system.

But suppose a King fan purchased a copy of the Wintel-based downloadable story and asked a friend to reverse-engineer a way of reading the story on his Macintosh or Linux computer. That bit of inventiveness might create liability for the friend under the Digital Millennium Copyright Act, according to several DMCA experts.