LANGLEY, Va. -- The National Security Agency, the government's code-breaking agency, yesterday released dozens of secret Soviet messages decoded during the 1940s, including new evidence that convicted American spies Julius and Ethel Rosenberg worked to pass atomic bomb and other military secrets to the Soviet Union.
The 49 documents released yesterday at CIA headquarters reveal that the couple, executed for conspiring to commit espionage in 1953, received money from their Soviet contacts, photographed information and recruited others.
The decoded messages may bring an end to a long-running controversy about the Rosenbergs' activities. Family members and sympathizers for years have claimed the two were victims of anti-Communist hysteria and unfairly convicted.
Yesterday's disclosures, the first release of Cold War intercepts, were extraordinary because knowledge about codes is among the most tightly guarded secrets in the intelligence community.
But the nation's spy agencies are attempting to bring secrets of the past into the open. The CIA recently released satellite photographs that showed Soviet missiles and other weapons in the early 1960s.
The intelligence agencies are clearly highlighting their past successes while Congress is in the middle of budget negotiations. Some lawmakers have called for drastic cuts.
The cables released yesterday were among 2,200 documents produced from 1943-1946 by U.S. intelligence officers who intercepted Soviet diplomatic and KGB cables and cracked the codes.
The code breakers discovered that at least 200 agents were spying for the Soviets on targets ranging from the atomic bomb to U.S. jet aircraft to radar and rocket programs. Some of those agents were eventually prosecuted.
John M. Deutch, the director of central intelligence, said the code-breaking project -- dubbed "Venona" -- "helped U.S. law enforcement officials identify Soviet operatives and their agents in the United States and elsewhere. This is the stuff of spy novels."
The decrypted messages were never used in the trial of the Rosenbergs and other spies on the Soviet payroll, since they were considered too classified to be used in open court, said David Kahn, scholar in residence at NSA's National Cryptologic Museum and author of "The Codebreakers."
"It seems to me that the Venona intercepts show one thing beyond doubt, that the Rosenbergs spied for the Soviet Union against the United States," he said.
Ronald Radosh, author of "The Rosenberg File: The Search for rTC the Truth," said the documents offer "the first solid new evidence since the release of FBI papers" in the early 1980s, apart from "tidbits released by the former Soviet Union."
"This shows, as we suspected, that the ring was about much more than atomic espionage" and included attempts to gain information on many other U.S. military programs, said Mr. Radosh, who concluded from his own research that the Rosenbergs were guilty.
But Walter and Miriam Schneir, historians who argue that the case against the Rosenbergs was not proven, disagree. More study is going to be necessary to determine the nature of Julius Rosenberg's involvement, Mr. Schneir said last night, adding, "Nothing in these documents implicates Ethel as being part of any [spy] group."
The decrypted cables between New York and Moscow reveal some of the clandestine activities of several other spies, including Klaus Fuchs, code named REST, a German-born physicist who worked on the U.S. atomic bomb project. He was later arrested in London for espionage and admitted he spied for the Soviets.
Information derived from the Venona translations shows the KGB's extensive contacts with the American Communist Party and the espionage activities of its members. The Army Signals Intelligence Agency, NSA's predecessor, broke the Soviet cables 1943 and continued decoding them until 1946, when the Soviets learned their messages were being read and switched codes. "We don't know the source or the exact time of the compromise," said Vice Adm. John M. McConnell, NSA's director.
But the British spy Kim Philby years later admitted telling the Soviets of the Venona secret. He was posted to Washington in the late 1940s as the British liaison to the CIA. At times he stood smoking his pipe watching the American codebreakers decrypt the dispatches.
After its creation in 1952, NSA continued to try to exploit the information from the dispatches, finally stopping in 1980, officials said.
"People continued to work on Venona so long as the possibility remained that counterintelligence information might be developed that could reveal new agents or espionage activities that might still be active," said William P. Crowell, NSA's deputy director, who managed the project in the early 1960s.
The remaining material produced by the Venona code breakers will be unveiled in several batches during the next year, the first in September.
Mr. Crowell declined to say whether the future disclosures will shed light on the case of Alger Hiss, the former State Department official and Baltimore native who was accused of spying and convicted of perjury during the 1950s. Mr. Hiss has consistently proclaimed his innocence.
The decoded messages had some interesting tidbits: Julius Rosenberg was code named "ANTENNA" and later "LIBERAL" in the cables sent to Moscow from Soviet agents in New York. One cable, dated June 14, 1944, says an agent's apartment is needed "for photographing the material of ANTENNA's group."
The following November, another cable discussed Ethel Rosenberg and used the code word "fellowcountryman," which cryptanalysts learned was the code for Communist.
A year later, a cable sent from Moscow to New York says a "decision was made about awarding the sources as a bonus the following sums: to LIBERAL 4000 dollars."
Mr. Deutch noted that the code names also reflected something "astonishing" -- KGB humor.
"Washington is referred to as Carthage, San Francisco is referred to by the code name Babylon and New York is referred to as Tyre -- all ancient cities that came to ruin," he said.
Among those in attendance yesterday in the vast marble entrance hall of CIA headquarters were 11 retired intelligence officers who took part in the Venona program.
Cecil Phillips, 70, of Silver Spring, recalled that the group of code breakers painstakingly uncovered the Soviet code "a number at a time, a letter at a time."
The complex coding systems used by the Soviets should have been impossible to decrypt.
A Soviet code clerk would take the message and convert it into numbers using a code book. The message was further encrypted by use of a "one-time pad," a unique random code for each message, converting words to numbers in a pattern used only once.
But the Venona team found the one-time pad was used more than once -- a breach of security.
"Each new recovery came with the elation akin to finding a pearl in an oyster," said Mr. Crowell, NSA's deputy director. "But each recovery also led to renewed work and grudging work."
And Mr. Crowell noted that the American decoders labored over their mathematical efforts to break the codes without the help of any modern devices, such as the computer or even a hand-held calculator.
EXCERPTS From: New York
27 November 1944
To VICTOR (i)
Your no. 5356 (a). Information on LIBERAL's (ii) wife (iii). Surname that of her husband, first name ETHEL, 29 years old. Married five years. Finished secondary school. A FELLOWCOUNTRYMAN (AEMLYaK) (iv) since 1938. Sufficiently well developed politically. Knows about her husband's work and the role of METR (v) and NIL (vi). In view of delicate health does not work. Is characterized positively and as a devoted person.
NOTES: (a) Not available
COMMENTS: (i) VIKTOR: Lt. Gen P. M. Fitin.
(ii) LIBERAL: Julius Rosenberg.
(iii) Ethel ROSENBERG, nee Greenglass.
(iv) ZEMLYaK: Member of the Communist Party.
(v) METR: Probably Joel BARR or Alfred SARANT.
(vi) NIL: Unidentified.