"Ex post facto" laws relate only to criminal laws passed by legislations. It does not apply to civil laws "that affect private rights adversely." In 2003 the US Supreme court noted the difference between civil and penal laws. In the case of Smith v. Doe, the court questioned the constitutionality of the Alaska Sex Offender Registration Act's retroactive requirements. Alaska's Megan's Law was applied to sex offenders before the law went into effect. It required offenders to register with the local police. It also required public notification via the Internet. The court made a legal precedent in deciding the intent of the law was civil and non-punitive. That it was to protect the public saftey by "protecting the public from sex offenders."