Apostille or Signature Authorization
On October 15, 1981, the United States became part of the 1961 Hague Convention abolishing the requirement of Legalization of Foreign Public Documents. The Convention simplified the authentication process of public documents to be used in nations that are members of the 1961 Hague Convention. Only those nations party to the Hague Treaty will recognize the apostille certification.
If a document is going to be used in a nation not party to the 1961 Hague Convention, then a certification certificate is used in place of an apostille. These foreign governments also require the U.S. Department of State and the Embassy or Consulate of the foreign nation where the document is to be used to authenticate the document in order for it to be considered legal.