A California man today pleaded guilty to federal charges for participating in a “brute force” hack on AT&T that yielded the personal data of 120,000 iPad owners.

During an appearance in U.S. District Court in Newark, New Jersey, Daniel Spitler, 26, copped to identity theft and conspiracy charges. Each felony count carries a maximum prison term of five years and a $250,000 fine.

According to prosecutors, Spitler, pictured in the adjacent mug shot, helped write the computer code that allowed him and fellow members of the “Goatse Security” hacking collective to gain unauthorized access to AT&T computer servers holding details on iPad purchasers like Diane Sawyer, Rahm Emanuel, and Michael Bloomberg.

In a press release today, a Department of Justice spokesperson noted that a list of stolen e-mail addresses was provided to the blog Gawker, “which published the stolen information in redacted form, along with an article concerning the breach.”

The criminal case against Spitler’s codefendant, Andrew Auernheimer, is pending, though a May 31 court filing indicates that the 25-year-old’s lawyer is in the midst of  negotiations to “finalize a plea agreement.”

According to a June 2010 criminal complaint, immediately after the AT&T hack Spitler “was afflicted by ‘post-troll paranoia’” and sought advice from fellow hackers about his legal exposure. The complaint also quotes him telling Auernheimer, “I hit fucking oil” when he breached AT&T’s servers.

Later, when Auernheimer told of his plans to publicize the hack, Spitler eschewed involvement in the forthcoming media campaign. “I’d like my anonaminity,” he wrote in an online chat session. “sry dunno how legal this is or if they could sue for damages.”

Spitler is scheduled to be sentenced on September 28.