World War I-era Documents Secret No More

The CIA said it has declassified the US government’s six oldest classified documents. Dating from 1917 and 1918, these documents describe secret writing techniques of that era. Agency officials believe they were the last remaining classified documents from the World War I period. “These documents remained classified for nearly a century until recent advancements in technology made it possible to release them,” said CIA Director Leon Panetta in the agency’s release. One document outlines the chemicals and techniques necessary for developing certain types of secret writing ink and a method for opening sealed letters without detection. Another, dated June 14, 1918, and written in French, reveals the formula used for German secret ink. The documents are housed at the National Archives.