 Complete the following phrase:  The origins of the National Security Agency can be traced back to April 28, 1917, three weeks after the U.S. Congress declared war on Germany in World War I. A code and cipher decryption unit was established as the Cable and Telegraph Section which was also known as the Cipher Bureau. It was headquartered in Washington, D.C. and was part of the war effort under the executive branch without direct Congressional authorization. During the course of the war, it was relocated in the armys organizational chart several times. On July 5, 1917, Herbert O. Yardley was assigned to head the unit. At that point, the unit consisted of Yardley and two civilian clerks. It absorbed the Navys cryptanalysis functions in July 1918. World War I ended on 