PICKING locks can presage a crime—or be a useful skill for those who lose their keys. Cracking the digital-rights management (DRM) that secures works that are distributed electronically, such as e-books and films, is illegal in many countries. But it can be tempting when rules seem unfair or arbitrary. Calibre, a free software programme, can be fitted with a third-party plug-in to strip the DRM from proprietary e-book formats. It has over 11m users. Other more furtive means are available too. David Price, head of piracy intelligence at NetNames, a brand-protection firm, says no DRM system has yet remained uncracked.

Stoking the trend is consumers’ growing realisation that they may not be (as they often think) buying their e-books, music downloads and other digital content outright. In many cases they are in effect just renting them, subject to tough rules buried in small print. Proprietary software can tie the e-book to a particular device. And the provider of the content can revoke the owner’s rights at whim.

Last month Amazon blocked a Kindle account belonging to Linn Jordet Nygaard, a Norwegian, meaning that she could no longer read the 43 books she had bought (after a burst of publicity Amazon restored the account, though it declined to explain its actions to her, or to comment publicly on the case). The European Consumers’ Organisation denounces “copyright shackles” on online content, and berates the European Commission for having “dallied” on ruling whether DRM is unfair.

For most digital libertarians, who believe DRM stifles competition and traps consumers, that will not be enough. Cory Doctorow, a blogger and author (who gives his books away free on the internet) says “rotten lawmaking” has set market terms that nobody wants—including many authors and publishers, who would prefer a more open system. In July Macmillan was the first book publisher of the “Big Six” to free its science fiction and fantasy e-book range from DRM. It termed the restrictions on copying and moving content a “constant annoyance”, for readers. In August Harvard Business Review Press launched an outlet for e-books, also DRM-free.

In October sales of the “Humble eBook Bundle”, a package of no-locks books for which consumers paid whatever they wanted (and chose how to split it between the author and a charity), was a big success. The average price paid was a record $14. Consumers seem to reward authors who trust them with their content.

Correction: This article has been corrected to make clear that it is not the Calibre software itself, but a third-party plug-in, that strips the DRM from copyright material.