WASHINGTON (AP) — Elizabeth Smart, who has been keeping a low profile since her kidnapping ordeal ended last month, appeared at the White House Wednesday to watch President Bush sign a sweeping child protection bill that encourages states to set up Amber Alert systems to find abducted children.

Elizabeth, a 15-year-old from Salt Lake City, Utah, smiled shyly but said nothing, as she stood in the Rose Garden with the president. Her parents, Ed and Lois Smart, who helped push for the legislation, wrapped their arms around their daughter, who wore a pastel dress, her blonde hair pulled back with a white bow.

Senate Judiciary Committee Chairman Orrin Hatch, R-Utah, said he spoke briefly with Elizabeth and her parents, who were overjoyed that Bush signed the Protect Act.

The legislation provides matching grants to states and communities for equipment and training to expand alert systems across America. Already operating in 41 states, such networks quickly distribute information about kidnapped children and their abductors.

The alert systems are named after Amber Hagerman, a 9-year-old girl abducted in Arlington, Texas, and later found murdered.

It also includes stiffer federal penalties for crimes against children and gives prosecutors new tools to fight child pornography.

"I hugged her," said Hatch, who was instrumental in adding stronger criminal penalties to the Amber Alert bill. "I told her I was proud of her. She basically smiled and said hi. That was enough for me."

The Smarts are scheduled to appear Friday on "The John Walsh Show," a syndicated television program.

Last June, Elizabeth, then 14, was taken at knifepoint from her bedroom. She returned to her family March 12 after she was spotted in a Salt Lake City suburb with transients Brian Mitchell and Wanda Barzee.

Mitchell, 49, and Barzee, 57, have been charged with burglary, kidnapping and sexual assault. They are both being held on $10 million bond and will soon undergo mental health evaluations.

Details of Elizabeth's ordeal have dribbled out slowly -- she was kept prisoner in the hills above her family's home, for example, and she and the two suspects were spotted in the San Diego area. But many details have been kept secret and the family has toned down its public profile.

Since being found with a self-proclaimed prophet, Elizabeth has spent a lot of time with her family and friends. She's going to church, making trips to the mall, but has refrained from public appearances.