The Digital Millennium Copyright Act (DMCA) at 17 U.S.C. §1201(a) prohibits the circumvention of technological protection measures used by copyright owners to prevent copying. However, subsection (a)(1)(C) allows the United States Copyright Office every three years to exempt certain classes of copyrighted works from the circumvention prohibition if the prohibition is likely to adversely affect users in their ability to make noninfringing uses of those particular classes of works.

The Librarian of Congress, James H. Billington, on July 26 announced six new or more specifically defined classes of works to be exempted from the DMCA’s prohibition against circumvention of access-control technologies. “Persons who circumvent access controls in order to engage in noninfringing uses of works in these six classes will not be subject to the statutory prohibition against circumvention,” Billington said.

The six classes of works are:
(1) Motion pictures on DVDs that are lawfully made and acquired and that are protected by a content scrambling system when circumvention is accomplished solely in order to accomplish the incorporation of short portions of motion pictures into new works for the purpose of criticism or comment, and where the person engaging in circumvention believes and has reasonable grounds for believing that circumvention is necessary to fulfill the purpose of the use in the following instances: (i) educational uses by college and university professors and by college and university film and media studies students; (ii) documentary filmmaking; and (iii) noncommercial videos
(2) Computer programs that enable wireless telephone handsets to execute software applications, where circumvention is accomplished for the sole purpose of enabling interoperability of such applications, when they have been lawfully obtained, with computer programs on the telephone handset.

(3) Computer programs, in the form of firmware or software, that enable used wireless telephone handsets to connect to a wireless telecommunications network, when circumvention is initiated by the owner of the copy of the computer program solely in order to connect to a wireless telecommunications network and access to the network is authorized by the operator of the network.

(4) Video games accessible on personal computers and protected by technological protection measures that control access to lawfully obtained works, when circumvention is accomplished solely for the purpose of good faith testing for, investigating, or correcting security flaws or vulnerabilities, if: (i) the information derived from the security testing is used primarily to promote the security of the owner or operator of a computer, computer system, or computer network; and (ii) the information derived from the security testing is used or maintained in a manner that does not facilitate copyright infringement or a violation of applicable law.

(5) Computer programs protected by dongles [Wikipedia explanation ] that prevent access due to malfunction or damage and which are obsolete. A dongle shall be considered obsolete if it is no longer manufactured or if a replacement or repair is no longer reasonably available in the commercial marketplace; and

(6) Literary works distributed in e-book format when all existing e-book editions of the work (including digital text editions made available by authorized entities) contain access controls that prevent the enabling either of the book’s read-aloud function or of screen readers that render the text into a specialized format.

It is the second of the above classes which removes copyright law prohibitions against “jailbreaking”, so long as the jailbreaking is done for the purpose of engaging in noninfringing uses. Jailbreaking is a process that allows iPhone users to run third-party code on their devices by unlocking the operating system and allowing the user root access. Once jailbroken, iPhone users are able to download applications which are not available through Apple’s App Store (and which, therefore, have not been approved by Apple).  It should be noted that, as reported by Jay Yarow in the San Francisco Chronicle, Apple CEO Steve Jobs claimed at the unveiling of the iPhone 4 that Apple approves 95% of the apps it sees within 7 days.

Though jailbreaking is no longer prohibited under the DMCA’s circumvention prohibitions, such activity, as Apple has previously stated, could amount to a breach of the phone owner’s end user license agreement, could nullify the product warranty, could result in Apple denying service for the product, and, according to Apple, could result in “instability, disruption of services, and compromised security.”  Given these potential negative consequences and the fact that Apple had apparently not actively pursued jailbreakers even prior to this decision, it remains to be seen what practical effect the decision will have for consumers.