BY HENRY CORRIGAN-GIBBS ILLUSTRATIONS BY BRIAN STAUFFER 58 NOVEMBER/DECEMBER 2014 Four decades ago, university researchers figured out the key to computer privacy, sparking a battle with the National Security Agency that continues today. STANFORD 59 federal laws prohibiting arms trafficking, communication of atomic secrets and disclosure of classified information. Without naming Hellman or his co- authors, Meyer specified the issues of IEEE’s Transactions on Information your research could help solve a looming national problem, but Theory journal and Computer magazine government officials thought publishing it would be tantamount in which Hellman’s articles appeared. to treason? A Stanford professor and his graduate students found Meyer concluded ominously that “these themselves in that situation 37 years ago, when their visionary work modern weapons technologies, uncon- trollably disseminated, could have more on computer privacy issues ran afoul of the National Security Agen- than academic effect.” cy. At the time, knowledge of how to encrypt and decrypt informa- Meyer’s letter alarmed many in the tion was the domain of government; the NSA feared that making the academic community and drew coverage secrets of cryptography public would severely hamper intelligence by Science and the New York Times for operations. But as the researchers saw it, society’s growing depen- two main reasons. First, the letter sug- gested that merely publishing a scientific dence on computers meant that the private sector would also need paper on cryptography would be the legal effective measures to safeguard information. Both sides’ concerns equivalent of exporting nuclear weapons proved prescient; their conflict foreshadowed what would become a to a foreign country. If Meyer’s interpre- universal tug-of-war between privacy-conscious technologists and tation of the law was correct, it seemed security-conscious government officials. to place severe restrictions on research- ers’ freedom to publish. Second, Debo- ment’s longstanding domestic monopoly rah Shapley and Gina Kolata of Science A CONTROVERSIAL on cryptography deeply annoyed many magazine discovered that Meyer was an SYMPOSIUM in the intelligence community. The NSA NSA employee. The International Symposium on Infor- acknowledged that Diffie and Hellman As soon as Hellman received a copy of mation Theory is not known for its racy had come up with their ideas without the letter, he recognized that continuing content or politically charged presenta- access to classified materials. Even so, to publish might put him and his stu- tions, but the session at Cornell Univer- in the words of an internal NSA history dents in legal jeopardy, so he sought sity on October 10, 1977, was a special declassified in 2009 and now held in the advice from Stanford University counsel case. In addition to talks with titles like Stanford Archives, “NSA regarded the John Schwartz. “Distribution-Free Inequalities for the [Diffie-Hellman] technique as classified. In his memo to Schwartz, Hellman Deleted and Holdout Error Estimates,” Now it was out in the open.” made a lucid case for the value of public- the conference featured the work of a The tension between Hellman and the domain cryptography research. Astutely, group from Stanford that had drawn the NSA only worsened in the months lead- Hellman first acknowledged that the U.S. ire of the National Security Agency and ing up to the 1977 symposium. In July, government’s tight control over crypto- the attention of the national press. The someone named J. A. Meyer sent a shrill graphic techniques proved enormously researchers in question were Martin letter to the Institute of Electrical and useful in World War II: Allied forces used Hellman, then an associate professor of Electronics Engineers, which had pub- confidential cryptographic discoveries to electrical engineering, and his students lished Hellman’s papers and was holding improve their own encryption systems Steve Pohlig, MS ’75, PhD ’78, and Ralph the conference. It began: while denying those same cryptographic Merkle, PhD ’79. benefits to Axis powers. Even so, Hellman A year earlier, Hellman had published I have noticed in the past months argued that circumstances had changed. “New Directions in Cryptography” with that various IEEE Groups have his student Whitfield Diffie, Gr. ’78. The been publishing and exporting [T]here is a commercial need paper introduced the principles that now technical articles on encryption today that did not exist in the 1940’s. form the basis for all modern cryptogra- and cryptology—a technical field The growing use of automated infor- phy, and its publication rightfully caused a which is covered by Federal Regu- mation processing equipment poses stir among electrical engineers and com- lations, viz: ITAR (International a real economic and privacy threat. puter scientists. As Hellman recalled in a Traffic in Arms Regulations, 22 Although it is a remote possibility, 2004 oral history, the nonmilitary com- CFR 121-128). the danger of initially inadver- munity’s reaction to the paper was “ecstat- tent police state type surveillance ic.” In contrast, the “NSA was apoplectic.” Meyer’s letter asserted that the IEEE through computerization must be The fact that Hellman and his stu- and the authors of the relevant papers considered. From that point of view, dents were challenging the U.S. govern- might be subject to prosecution under inadequate commercial cryptogra- 60 NOVEMBER/DECEMBER 2014 phy (which our publications are tographic algorithms could constitute decision up to the students. trying to avoid) poses an internal “export” of arms. It was not clear, how- According to Hellman, Merkle and national security threat. ever, that a prosecution under this act Pohlig at first said, “We need to give the would stand up to a legal challenge on papers, the hell with this.” After speak- In the memo, Hellman described how First Amendment grounds. ing with their families, though, the stu- his earlier attempts to prevent “stepping Evaluating these laws together, dents agreed to let Hellman present on on [the] toes” of the NSA failed when the Schwartz concluded that Hellman and his their behalf. agency’s staffers would not even disclose students could legally continue to pub- In the end, the symposium took place which areas of cryptography research lish. At the same time, Schwartz noted without incident. Merkle and Pohlig stood Hellman should avoid. wryly, “at least one contrary view [of the on stage while Hellman gave the presen- Responding to Hellman a few days law] exists”—that of Joseph A. Meyer. tation. The fact that the conference went later, Schwartz opined that publishing Hellman later recalled Schwartz’s less- ahead as planned, Science observed, “left cryptography research would not in itself than-comforting informal advice: “If you little doubt that the work [in cryptogra- violate federal law. His findings had a are prosecuted, Stanford will defend you. phy] has been widely circulated.” That a strong legal basis: Two regulations gov- But if you’re found guilty, we can’t pay group of nongovernmental researchers erned classified information in the United your fine and we can’t go to jail for you.” could publicly discuss cutting-edge cryp- States at the time—an executive order and The Cornell symposium was to begin tographic algorithms signaled the end of the Atomic Energy Act of 1954—and nei- three days after Schwartz offered his legal the U.S. government’s domestic control ther seemed to prevent the publication of opinion; Hellman, Merkle and Pohlig had of information on cryptography. unclassified research on cryptography. to quickly decide whether to proceed There was only one other likely legal with their presentations in spite of the tool that the federal government could threat of prosecution, fines and jail time. THE VIEW FROM use to prevent the Stanford group from Graduate students typically present their FORT MEADE disseminating their work: the Arms own research at academic conferences, Vice Adm. Bobby Ray Inman took over as Export Control Act of 1976, which regu- but according to Hellman, Schwartz rec- director of the NSA in the summer of lated the export of military equipment. ommended against it in this case. Since 1977. Inman was an experienced naval Under a generous interpretation of the the students were not employees of Stan- intelligence officer with allies in both law, giving a public presentation on cryp- ford, it might be more difficult for the political parties. If his qualifications for university to justify paying their legal the job were good, his timing was not. He bills. Schwartz also reasoned that dealing had barely warmed his desk chair when SHARING THE STEALTH: Merkle, Hellman and Diffie with a lengthy court case would be harder he was thrust into the center of what he ended government’s for a young PhD student than for a ten- recently described as “a huge media monopoly on cryptography. ured faculty member. Hellman left the uproar” over the J. A. Meyer letter—written the very first day of Inman’s tenure. Although Inman was concerned about the impact that publication of these new cryptographic techniques would have on the NSA’s foreign eavesdropping capabilities, he was also puzzled. As he explained, the primary consumers of cryptographic equipment in the 1970s were governments. Apart from that, “the only other people early on . who were buying encryption to use were the drug dealers.” Since the NSA already had “incredibly able people working on build- ing the systems to be used by the U.S. gov- ernment” and the NSA had no interest in protecting the communications of drug dealers, Inman wanted to find out why these young researchers were so focused on cryptography. In the tradition of intelligence profes- sionals, Inman set out to gather some information for himself. He went to Cali- CHUCK PAINTER/STANFORD NEWS SERVICE SERVICE NEWS CHUCK PAINTER/STANFORD fornia to meet with faculty members and STANFORD 61 industry leaders at Berkeley, Stanford and as a crucial piece of a functioning techno- To reckon with the growing threat of elsewhere.