CHICAGO (CBS) – Gov. Pat Quinn has signed the so-called “Facebook Bill” into law, barring employers from asking job applicants and employees for their social network passwords.

The law takes effect Jan. 1.

Quinn says privacy is fundamental.

Some law enforcement authorities in the state have argued that they need the right to ask for social network passwords so they can get a complete picture of an applicant’s life.

LISTEN: WBBM Newsradio’s Steve Miller reports

But Ed Yohnka, spokesman for the Illinois branch of the American Civil Liberties Union, doesn’t buy that.

“There are all sorts of investigative devices that, of all people, law enforcement has to examine and think about the backgrounds of the people that they hire,” he said. “What they don’t need to know is what they think about politics or other things, which are often the kinds of things people post on their Facebook account.”

Illinois will become only the second state with a Facebook Law.