I want to study abroad. How can I authenticate my U.S. diploma?
Since October 15, 1981, the United States has been part of the 1961 Hague Convention abolishing the Requirement of Legalization for Foreign Public Documents (Only). The Convention provides for the simplified certification - the "apostille"- of public documents to be used in countries that have joined the convention.
Since the majority of education-related documents are executed and signed by state officials, in order to obtain the apostille you would need to contact the state department for the state where the documents were issued. General contact information for all states is available here .
Documents requiring certifications with an apostille by the U.S. Department of State (federal agency) are those that have been signed by a federal official with the official Seal of that agency, American Consular Officer, Military Notary (10 USC 1044a) or Foreign Consul (Diplomat Officials must be registered with the Office of Protocol).