Turing's last two papers on Enigma decryption have been released to Britain's National Archives; the seven decades' delay had been due to their "continuing sensitivity... It wouldn't have been safe to release [them earlier]." Holocaust intelligence Historians and Holocaust researchers have tried to establish when the Allies realized the full extent of Nazi-era extermination of Jews, and specifically, the extermination-camp system. In 1999, the U.S. Government passed the Nazi War Crimes Disclosure Act (P.L. 105-246), making it policy to declassify all Nazi war crime documents in their files; this was later amended to include the Japanese Imperial Government. As a result, more than 600 decrypts and translations of intercepted messages were disclosed; NSA historian Robert Hanyok would conclude that Allied communications intelligence, "by itself, could not have provided an early warning to Allied leaders regarding the nature and scope of the Holocaust." Following Operation Barbarossa, decrypts in August 1941 alerted British authorities to the many massacres in occupied zones of the Soviet Union, including those of Jews, but specifics were not made public for security reasons. Revelations about the concentration camps were gleaned from other sources, and were publicly reported by the Polish government-in-exile, Jan Karski and the WJC offices in Switzerland a year or more later. A decrypted message referring to "Einsatz Reinhard" (the Höfle Telegram), from January 11, 1943, may have outlined the system and listed the number of Jews and others gassed at four death camps the previous year, but codebreakers did not understand the meaning of the message. In summer 1944, Arthur Schlesinger, an OSS analyst, interpreted the intelligence as an "incremental increase in persecution rather than... extermination." Postwar consequences There has been controversy about the influence of Allied Enigma decryption on the course of World War II. It has also been suggested that the question should be broadened to include Ultra's influence not only on the war itself, but also on the post-war period. F. W. Winterbotham, the first author to outline the influence of Enigma decryption on the course of World War II, likewise made the earliest contribution to an appreciation of Ultra's postwar influence, which now continues into the 21st century—and not only in the postwar establishment of Britain's GCHQ (Government Communication Headquarters) and America's NSA. "Let no one be fooled," Winterbotham admonishes in chapter 3, "by the spate of television films and propaganda which has made the war seem like some great