Code breaking is an integral part of the creation of cryptosystems. The security of today's cryptosystems comes not from secrecy about how they work, but peer review to weed out the ones that may break easily. That means those who produce cryptosystems also try to crack them. Lately, however, the government has taken a dim view on those who break cryptosystems.
Laws against breaking the encryption protecting cable and satellite TV have been in the books for a while. Recently the Digital Millennium Copyright Act (DMCA) was passed making it a crime to break codes protecting copyrighted content[4, DMCA]. Essentially this creates a catch-22: even though you may have the legal right to use a copyrighted work, you are not allowed to remove the protection that is preventing you from using it. Two big cases brought this to the attention of programmers everywhere.
The first public case was against the 2600 magazine for publishing the source code to a utility called decss, which decrypts DVDs into a form where they can be played under Linux. A Linux user who owned a DVD and wanted to play their DVD would use this utility, however because playing a DVD requires decrypting it first, decss ran afoul of the DMCA. 2600 was prohibited from publishing the source code or information about where to find the source code.
The second case was against a Russian programmer named Dmitri Sklyarov, who wrote a program to convert adobe ebooks into other file formats. While legal in Russia, the US considers this a crime because converting the ebook requires first decrypting it. When Dmitri flew to the US to attend a programmer conference, Adobe noticed his name and had the US arrest him. Thankfully, he was released back to his wife and kids under the condition that he would testify against his employer.