LOS ANGELES - A hacker who infiltrated the network of T-Mobile USA Inc. and accessed personal information of hundreds of customers, including a Secret Service agent, was sentenced Monday to one year of home detention.

Nicholas Lee Jacobsen, 23, must also pay $10,000 in restitution to T-Mobile to cover losses caused by his acts, which took place in 2004.

The former Santa Ana resident who now lives in Oregon said he lacked "comprehension and maturity" when he targeted the network of Bellevue, Wash.-based T-Mobile USA, uncovering the names and Social Security numbers of 400 customers.

"I did some very stupid things," Jacobsen told U.S. District Judge George King at his sentencing Monday in Los Angeles.

Jacobsen was able to read some sensitive information that Special Agent Peter Cavicchia could access through his wireless T-Mobile Sidekick device. No investigations were compromised, the Secret Service said.

"What you've done is very dangerous to others. Maybe you didn't fully appreciate that, perhaps because of your youth," King told Jacobsen Monday.

Jacobsen could have faced a maximum sentence of five years in prison and a fine of up to $250,000 for the crime, accessing a protected computer.