The U.S. Army's Signal Intelligence Service, the precursor to the National Security Agency, began a secret program in February 1943 later codenamed VENONA

The mission of this small program was to examine and exploit Soviet diplomatic communications but after the program began, the message traffic included espionage efforts as well.

Although it took almost two years before American cryptologists were able to break the KGB encryption, the information gained through these transactions provided U.S. leadership insight into Soviet intentions and treasonous activities of government employees until the program was canceled in 1980.

The VENONA files are most famous for exposing Julius (code named LIBERAL) and Ethel Rosenberg and help give indisputable evidence of their involvement with the Soviet spy ring.

The first of six public releases of translated VENONA messages was made in July 1995 and included 49 messages about the Soviets' efforts to gain information on the U.S. atomic bomb research and the Manhattan Project. Over the course of five more releases, all of the approximately 3,000 VENONA translations were made public.

 2SEP_PEL.PDFZVUK reports FBI's investigation of PEL 2 September 1943 (Release 2)
 26JUN_ZORIN_TRIP_SF.PDFZORIN's trip to San Francisco 26 June (Release 3)
 08JAN_ZILLIACUS_P1.PDFZILLIACUS describes situation in Finland to "KLARA"
 08JAN_ZILLIACUS_P2.PDFZILLIACUS describes situation in Finland to "KLARA"
 8JUL_ZHEROM_MARTA.PDFZhEROM and MARTA; and DIK requests repeat of telegram
 8DEC_OGYUST.PDFYUKHO and Wife, "STEGE'S" Release, OGYUST 8 December 1943 (Release 5)
 23JAN_YOUNG_MSG.PDFYOUNG Message and OLD Hand Over
 8MAY_YELESIN.PDFYeLESIN works as a Cipher Clerk
 20AUG_CHEMICAL_WORK.PDFWRITER: Intelligence on Chemical Work for Military Purposes in Britain and Germany
 17JUL_KGB_5TH_LINE.PDFWork of the KGB Fifth Line (security of the merchant fleet) 17 July (Release 4)
 4MAY_KLARIN.PDFWork of Senior KGB Officers Povel Klarin and Gen. Zubilin
 6MAY_KATZ.PDFWork of KGB Agent Joseph "Jack" Katz
 20MAR_ILLEGAL_ALBERT.PDFWork of Illegal ALBERT and G. Silvermaster in handling PAGE 20 March (Release 3)
 19JUL_SOVIET_OFFICIAL_WIFE.PDFWife of a Soviet official visiting U.S. 19 July 1943 (Release 4)
 27JUN_AMERICANS_PHOTOGRAPH.PDFWhat do the Americans propose to photograph? 27 June 1943 (Release 4)
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