Crackers have broken the encryption technology used to protect Stephen King's e-book, dispersing free pirated copies of the $2.50 electronic novel around the web.

Len Kawell, president of Glassbook, one of the publishers that are electronically distributing King's Riding the Bullet, said he knew of two sites upon which pirated versions of the e-book were posted.

Pirates broke the cracking method to open the PDF file that King's book was in. Publishers are working with the FBI to find the encryption breakers and be sure the sites do not offer the counterfeit copies of the book, which is only available in electronic form.

Kawell said the book was initially released using a 40bit encryption key, the strongest then available for export. The company has since updated to a 64bit key.

Earlier this month the 16,000-word novella, described by King as "a ghost story in the grand manner", was posted at Glassbook and several other sites for electronic distribution at a cost of $2.50 each.

While the monetary losses were likely negligible - the novella was being given away for free at many booksellers - the greater concern is that the piracy could scare off authors and publishers from this technology.