The growth of the Internet, and particularly distributed search engines like Kazaa and Gnutella, have represented a challenge for copyright policy. The Recording Industry Association of America, in particular, has been on the front lines of the fight against copyright infringement, which the industry calls "piracy". The industry has had victories against some services, including a highly publicized case against the file-sharing company Napster, and some people have been prosecuted for sharing files in violation of copyright. The electronic age has seen an increase in the attempt to use software-based digital rights management tools to restrict the copying and use of digitally based works. Laws such as the Digital Millennium Copyright Act have been enacted, that use criminal law to prevent any circumvention of software used to enforce digital rights management systems. Equivalent provisions, to prevent circumvention of copyright protection have existed in EU for some time, and are being expanded in, for example, Article 6 and 7 the Copyright Directive. Other examples are Article 7 of the Software Directive of 1991 (91/250/EEC), and the Conditional Access Directive of 1998 (98/84/EEC). This can hinder legal uses, affecting public domain works, limitations and exceptions to copyright, or uses allowed by the copyright holder. Some copyleft licenses, like GNU GPL 3, are designed to counter that. Laws may permit circumvention under specific conditions like when it is necessary to achieve interoperability with the circumventor's program, or for accessibility reasons; however, distribution of circumvention tools or instructions may be illegal.