Whitfield Diffie

His full name is Bailey Whitfield Diffie, and he is known as “Whit”; he was born on June 5, 1944, in Washington, D.C. U.S. Patent 4,200,770 lists him as an inventor under the name “Bailey W. Diffie.”⁠[1][2]

The biography written for the Association for Computing Machinery by Jeffrey R. Yost states that his father, Bailey Wally Diffie, taught Iberian history at the City College of New York, and that his mother, Justine Louise Whitfield, a writer and scholar, died while he was in high school; he grew up in a Jewish immigrant neighborhood in the Queens borough of New York City, a liberal environment that, in the biography’s view, shaped his longstanding countercultural ethos.⁠[1]

The same biography states that his grades at school were unremarkable but that he impressed people with his intellect, and that he read about cryptography and mathematics as a child.⁠[1]

In an interview with Franco Furger in 1992 he recalled that when he was ten years old his primary-school teacher, Mary Collins, taught the class about simple cryptosystems, and that he then got his father to bring him all the books on the subject from the City College library in New York, but tried to read Helen Gaines’s book without success; as a teenager he was more drawn to military matters, found cryptography unappealing and turned to other subjects.⁠[3]

The alumni profile of the Society for Science states that he was fascinated with cryptography from a young age and that an early aptitude in mathematics led him to compete in the Science Talent Search in 1961.⁠[4]

He graduated from the Massachusetts Institute of TechnologyMassachusetts Institute of TechnologyThe Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts, United States. It received its charter from Massachusetts in 1861, admitted its first students in 1865 and moved from Boston to its present campus in 1916. As of October 2025 it had 11,816 students, and it counts 106 Nobel laureates among members of its community.Open the full entry (MIT) in 1965 with a B.S. in mathematics; the MIT Alumni Association lists him as a member of the Class of 1965.⁠[1][5][6]

In the 1992 interview he described a “macho tradition” at MIT, in which a real person does anything that comes along, and said the institute was all male and politically very conservative; he said that during those years he spent two summers at BerkeleyUniversity of California, BerkeleyThe University of California, Berkeley (UC Berkeley) is a campus of the University of California system; the University of California was founded in 1868 through a merger of two institutions and moved to Berkeley, California, in 1873.Open the full entry, where he got better grades in the courses he took than at MIT, and that he liked Berkeley tremendously, calling it a very leftist campus.⁠[3]

The Association for Computing Machinery biography states that, to avoid being drafted for the Vietnam War, he accepted a job offer from the MITRE Corporation after graduating (research staff of this nonprofit could be shielded from military service) and worked there as a research assistant from 1965 to 1969; he worked under Roland Silver on a symbolic mathematics package that evolved into Macsyma, and spent more time at the MIT Artificial Intelligence Laboratory than at MITRE.⁠[1]

In the 1992 interview he said that working on Mathlab/Macsyma at MITRE taught him systems programming and got him interested in proving programs correct.⁠[3]

The Franklin Institute’s laureate profile of 1997 states that his interest in cryptology began in 1966, while he was working at the MIT artificial intelligence laboratory.⁠[7]

In 1969 John McCarthy invited him to join the Stanford Artificial Intelligence Laboratory at Stanford UniversityStanford UniversityStanford University is a research university in California founded by Leland and Jane Stanford in 1885 and opened in 1891.Open the full entry; the Association for Computing Machinery biography states that, by then too old to be drafted, he left MITRE and the MIT AI Laboratory for CaliforniaCaliforniaCalifornia is a U.S. state on the Pacific coast; its capital is Sacramento and its largest city is Los Angeles. California was admitted to the Union on September 9, 1850, as the 31st state. Its population at the 2020 Census (April 1, 2020) was 39,538,223, the largest of any state.Open the full entry, where he felt more culturally at home, worked at the laboratory as a research programmer from 1969 to 1973, and discussed networking, electronic keys and authentication with McCarthy. The Computer History Museum’s profile states that he came to the laboratory to work with its director, McCarthy, on proving that computer programs are correct.⁠[1][5]

In the 1992 interview he said that he later felt his approach to programming methodology differed from the formal-proof work of McCarthy’s group, and that around 1969–1970 he concluded he was an engineer at heart (“I decided I was an engineer.”) because he wanted to build things, although his work was mostly mathematical.⁠[3]

In the interview he recalled that he was worried about trust in shared computer systems and believed that cryptography could let users keep control of their files without relying on the system staff; around 1972, ARPA’s Larry Roberts asked the National Security Agency (NSA) for help in securing the ARPANET and was turned down, so McCarthy’s group designed a system itself, which he studied. The Tom Rocks Maths website, introducing his 2021 interview, states that he first learned about cryptography at school and returned to it after finishing his degree at MIT, while working as a researcher at the Stanford Artificial Intelligence Laboratory; it likewise states that McCarthy had met Larry Roberts by chance, that network security came up, and that when McCarthy returned to Stanford and explained the problem Diffie became hooked on it.⁠[3][8]

The Computer History Museum’s profile states that in the summer of 1972 his research shifted to cryptography; the Association for Computing Machinery biography states that David Kahn’s book The Codebreakers strongly shaped his interest; he himself said in the 1992 interview that he studied Kahn’s book slowly in the fall of 1972 and spent the spring of 1973 working almost exclusively on cryptography.⁠[5][1][3]

The Computer History Museum’s profile states that early in 1973 he took a leave of absence from Stanford to travel the United StatesUnited StatesThe United States is a federal country in North America made up of 50 states, the District of Columbia as the seat of government, and territories such as Puerto Rico and Guam; its capital is Washington, D.C. The Continental Congress adopted the Declaration of Independence on July 4, 1776. The 2020 census (April 1, 2020) counted a resident population of 331,449,281, and the 435 seats of the House of Representatives are apportioned among the states on the basis of the census.Open the full entry pursuing his interest in cryptography; the Association for Computing Machinery biography states that he left Stanford to study cryptography on his own, reconnected on a trip back to the Northeast with his friend Mary Fischer in New JerseyNew JerseyNew Jersey is a state in the eastern United States on the Atlantic Ocean, bordered by New York State, Delaware, and Pennsylvania, with the Hudson River forming its northeastern boundary and the Delaware River its western boundary; its capital is Trenton and its largest city is Newark. One of the original 13 colonies, it became the third state to ratify the U.S. Constitution on December 18, 1787, and its population in the 2020 census (April 1, 2020) was 9,288,994.Open the full entry, who became his partner and later his wife, and that in 1973 and 1974 the two travelled together to meet cryptography researchers.⁠[5][1]

The Tom Rocks Maths website, introducing his 2021 interview, states that to learn as much as he could about cryptography he visited researchers at Harvard UniversityHarvard UniversityHarvard University is a private research university in Massachusetts, established by the Massachusetts Bay Colony legislature in 1636 and named in 1639 for early benefactor John Harvard. Its principal campuses are in Cambridge and the Allston and Longwood neighborhoods of Boston. It includes Harvard College, graduate and professional schools, and the Radcliffe Institute for Advanced Study. Two governing boards share oversight. Alan M. Garber was president as of October 2026, and the endowment stood at $56.9 billion at the end of fiscal 2025.Open the full entry, MIT, IBMIBMIBM (International Business Machines Corporation) is an American information technology company, renamed in 1924 from the Computing-Tabulating-Recording Company (C-T-R).Open the full entry’s Watson research center and the National Security Agency.⁠[8]

In 1974 he visited IBM’s Thomas J. Watson Laboratory in Yorktown Heights, where Alan Konheim suggested that he contact Martin Hellman, a professor of electrical engineering at Stanford University (in the 1992 interview he recalled the visit as being in the summer of 1974 and Konheim as very secretive); in the fall of 1974 he asked Hellman for a meeting, and the planned short meeting turned into a discussion lasting many hours that continued through dinner at Hellman’s house and deep into the evening; the two then began to work together. The Computer History Museum’s profile states that he returned to Stanford with the support of Hellman, who was also researching cryptography.⁠[1][3][5]

Throughout 1975 he worked with Hellman; the Association for Computing Machinery biography states that he took a programming job in Hellman’s research group and, in the second half of 1975, at Hellman’s suggestion, enrolled as a doctoral student under Hellman but did not complete the degree, and that he was a graduate student and research assistant at Stanford from 1975 to 1978.⁠[5][1]

In the 1992 interview he said that secure telephone communication and digital signatures were problems he had been thinking about since the 1960s; he had been working on an enhanced identification-friend-or-foe (IFF) scheme, in which a response can be checked by someone who cannot construct it, and realized that the idea could be turned around to solve the problem that had been on his mind, which led him to the asymmetric key system; he believed the key idea came around May 1975, though he had lost the exact date because his notes were not kept securely; he first explained it to his wife as she came home from work, then walked down the hill to tell Hellman, taking about 45 minutes to convince him, and Hellman at once asked to co-author the paper; that first paper was written in December 1975 and appeared at the National Computer Conference in 1976. The profiles of Stanford University’s Center for International Security and Cooperation and of the Marconi Society both state that he is best known for the discovery of the concept of public-key cryptography in 1975, which he developed together with Hellman.⁠[3][9][10]

The Association for Computing Machinery biography states that in 1975 he and Hellman became aware of Ralph MerkleRalph MerkleRalph Merkle (born 1952) is a cryptographer and nanotechnology researcher regarded as one of the inventors of public-key cryptography: as an undergraduate he devised Merkle’s Puzzles, a method of key exchange over a public channel, and he later worked with Whitfield Diffie and Martin Hellman, with whom he shares the public-key patent; the Merkle tree he proposed is used in the Bitcoin white paper. He has since worked for many years on molecular nanotechnology and is a director of the cryonics organization Alcor.Open the full entry, a student at the University of California, Berkeley, who in 1974 had formulated what became known as Merkle’s puzzles; they judged their own key-distribution method far more compact than Merkle’s puzzles, and he considered Merkle’s knapsack system poorly suited to signatures; the biography also states that he called Merkle “possibly the most inventive character in the public-key saga.” In the interview he himself said that Merkle’s puzzles system was the earliest practical solution and called it “a fantastic discovery.”⁠[1][3]

The invited paper “New Directions in Cryptography,” written with Hellman, appeared in IEEE Transactions on Information Theory, vol. IT-22, no. 6, pp. 644–654, November 1976; the manuscript was received on June 3, 1976, his affiliation was given as the Department of Electrical Engineering and the Stanford Artificial Intelligence Laboratory of Stanford University, and the work was partly supported by the National Science Foundation (NSF). The paper opens by saying that cryptography stands “on the brink of a revolution.”⁠[11]

The paper proposes “public key distribution”: two users who have never communicated can agree on a shared key over a public channel; each keeps an exponent X secret and publishes Y = α^X mod q, and each derives the same key from the other’s public value and his own secret exponent, the security resting on the difficulty of computing logarithms modulo a prime q, while the paper notes that the equivalence of breaking the scheme to computing logarithms has not been proven. It also proposes “one-way authentication,” a digital, message-dependent signature that anyone can verify but only the legitimate signer can produce, and states that a public-key cryptosystem can be converted into a one-way authentication system.⁠[11]

The paper lists Ralph Merkle as reference 1, stating that he had independently studied the problem of distributing keys over an insecure channel and noting that his protocol requires many keys to be transmitted before one can be agreed on. The Computer History Museum’s profile states that Merkle joined their work in 1976 and that the paper’s insights underpin secure Internet transactions, including e-commerce.⁠[11][5]

The Association for Computing Machinery’s press release of 2016 states that the paper introduced public-key cryptography and digital signatures, the foundation of the most widely used Internet security protocols; secure web connections beginning with “https” use public-key cryptography to exchange a key and then symmetric encryption for the rest of the session.⁠[12]

On September 6, 1977, Martin E. Hellman, Bailey W. Diffie and Ralph C. Merkle filed a patent application titled “Cryptographic apparatus and method,” assigned to Stanford University (Leland Stanford Junior University); it was granted on April 29, 1980, as U.S. Patent 4,200,770, and its abstract describes a system for sending a computationally secure cryptogram over an insecure channel without prior agreement on a cipher key.⁠[2][1]

The Association for Computing Machinery biography states that Jim Omura licensed the patent for Cylink, which was selling hardware implementations by 1984, while most others used the RSA patent granted in September 1983.⁠[1]

From December 1978, he managed Secure Systems Research at BNR, Inc./Northern Telecom in Mountain View, California, for a dozen years, during which he designed the key-management architecture of Northern Telecom’s PDSO security for X.25 packet networks; the Royal Society’s profile states that after leaving Stanford in the late 1970s he managed Secure Systems Research at Bell-Northern Research, the laboratory of the Canadian telephone system.⁠[1][13][9]

In the 1992 interview he said that Ralph Merkle worked for him at Bell Northern Research in 1979 or 1980 and that the two did not get along very well; looking back, he judged himself to have been far too conservative, while Merkle wanted to go straight to public-key systems.⁠[3]

In 1991 he joined Sun Microsystems as a distinguished engineer and went on to be a Sun Fellow, vice president and chief security officer until he left in the spring of 2009. The Association for Computing Machinery’s press release of 2016 states that at Sun he was the chief exponent of the company’s security vision and responsible for its security strategy; he frequently presented at security conferences.⁠[9][10][12][1][13]

In 1992 the Swiss Federal Institute of Technology in Zurich awarded him an honorary doctorate in technical sciences.⁠[5][14][1]

That year he was interviewed in Palo Alto by Franco Furger about the development of public-key cryptography; the transcript, edited by Arnd Weber, was published by ITAS (Institut für Technikfolgenabschätzung und Systemanalyse) on January 16, 2002. In the interview he repeatedly says that his memory of dates and details is uncertain.⁠[3]

The Royal Society’s profile states that since 1993 he has concentrated on public policy concerning cryptography, security and privacy, opposing restrictions on the business and personal use of cryptography, and that he has been the subject of articles in the New York TimesThe New York TimesThe New York Times is an American morning daily newspaper published in New York City. Founded in 1851, it is published by The New York Times Company.Open the full entry Magazine, Wired and Discover and of television programs on CNNCNNCNN (Cable News Network) is an Atlanta-based news organization founded by Ted Turner on June 1, 1980, as the world’s first 24-hour television news channel. It has been owned in turn by Turner Broadcasting System, Time Warner, AT&T and Warner Bros. Discovery, became part of Skydance Corporation along with Warner Bros. Discovery in October 2026, and is one of the five networks that rotate in the White House television pool.Open the full entry, the Discovery Channel and Equinox. The Society for Science’s alumni profile mentions a Science News article of June 19, 1993, on his and his colleagues’ cryptographic work.⁠[13][4]

The Association for Computing Machinery biography states that from the early 1990s he testified repeatedly before congressional subcommittees on computer security, cryptography and privacy; its press release of 2016 states that he testified several times to the U.S. Senate and House of Representatives on the public-policy aspects of cryptography and has written more than 30 technical papers. The profile of Stanford University’s Center for International Security and Cooperation states that throughout the 1990s he worked for the right of individuals and businesses to use encryption.⁠[1][12][9]

In 1996 he received the National Computer Systems Security Award given jointly by the National Institute of Standards and Technology (NIST) and the National Security Agency. In 1997 the Franklin Institute awarded him and Hellman the Louis E. Levy Medal in computer and cognitive science, with the citation “For invention of public key cryptography and digital signatures”; at the time of the award he was a distinguished engineer at Sun Microsystems.⁠[1][9][7]

The Association for Computing Machinery biography gives 1997 as the year in which he and Hellman received the Paris Kanellakis Theory and Practice Award; the association’s press release of 2016 instead names it the 1996 Paris Kanellakis Theory and Practice Award, shared with Leonard Adleman, Hellman, Ralph Merkle, Ronald Rivest and Adi Shamir.⁠[1][12]

In 1998 The MIT Press published Privacy on the Line: The Politics of Wiretapping and Encryption, which he wrote with Susan Landau; a paperback followed in 1999 and an “Updated and Expanded Edition” in 2007. The Association for Computing Machinery biography states that the book examines the history of public-key cryptography, the debate over the key length of DES, the Clipper chip and wiretapping within broader legal and policy contexts. The copyright page of the 2007 edition states that the book enters the public domain after January 1, 2017, and that any holder may copy and redistribute the complete work without modification.⁠[15][1][16]

The same year he received the IEEE Information Theory Society’s Golden Jubilee Award for Technological Innovation.⁠[14][1]

In 1999 he, Hellman and Ralph Merkle received the IEEE Kobayashi Award.⁠[1]

In 2000 he received the Marconi Prize for his “invention of public-key cryptography to protect privacy on the Internet”; the prize was presented by the Marconi Foundation’s chairman, Martin Meyerson, and its president, John Jay Iselin, at Columbia UniversityColumbia UniversityColumbia University, formally Columbia University in the City of New York, is a private research university in New York City and a member of the Ivy League. Founded in 1754 by royal charter from King George II as King's College, it is the oldest institution of higher education in New York State and the fifth oldest in the United States. It was renamed Columbia College in 1784 and adopted the university name and moved to Manhattan's Morningside Heights in 1896. It has 17 schools and four affiliated colleges, with 35,978 students enrolled in fall 2025. Legal scholar Jennifer L. Mnookin became president on July 1, 2026.Open the full entry in New York City.⁠[10][12]

In 2004 he was named a Fellow of the International Association for Cryptologic Research (IACR).⁠[1]

After leaving Sun Microsystems in the spring of 2009, he was a visiting scholar (2009–2010) and an affiliate (2010–2012) at Stanford University’s Center for International Security and Cooperation (CISAC), and then became a consulting scholar there.⁠[9][1][14]

In 2010 he shared the IEEE Richard W. Hamming Medal with Martin Hellman and Ralph Merkle.⁠[5][12]

On May 14, 2010, Computerworld wrote that he had been hired as vice president for information security and cryptography at ICANNICANNICANN (the Internet Corporation for Assigned Names and Numbers) is a nonprofit public benefit corporation founded in California in 1998 and headquartered in Los Angeles. It coordinates the Internet’s unique identifiers worldwide, including the Domain Name System (DNS), IP addresses, and protocol parameters, and develops generic top-level domain policy through a multistakeholder model; in October 2016, the U.S. Government’s stewardship of the IANA functions passed to the global Internet community, and in 2026 ICANN opened the second application round of its New gTLD Program.Open the full entry (the Internet Corporation for Assigned Names and Numbers), to oversee the design, development and implementation of security methods for ICANN-managed networks and to advise the organization on security matters; the article states that the appointment came six months after he left Sun Microsystems, where he had last been a high-level adviser to the company; the article also states that ICANN had been criticized for not acting decisively against bad actors on the Internet, a problem he would inherit.⁠[17]

On March 25, 2011, the Computer History Museum recorded an oral history with him covering his upbringing and early interest in codes and ciphers, the meaning of cryptography, his early forays into the field under John McCarthy at the Stanford Artificial Intelligence Laboratory, his extended journey across the United States with his friend Mary, visiting research centers and investigating cryptography with leading figures in the field, his work at IBM’s Thomas Watson Research Center, his learning of Martin Hellman and joining his research, and the origin of the Diffie–Hellman public-key system and the collaboration with Ralph Merkle; the transcript is a 17-page PDF.⁠[18]

The same year he was made a Fellow of the Computer History Museum, “For his work, with Martin Hellman and Ralph Merkle, on public key cryptography.”⁠[5]

On July 6, 2015, the MIT Computer Science and Artificial Intelligence Laboratory issued the technical report “Keys Under Doormats: Mandating insecurity by requiring government access to all data and communications” (MIT-CSAIL-TR-2015-026), of which he was a co-author, together with Harold Abelson, Ross Anderson, Steven M. Bellovin, Josh Benaloh, Matt Blaze, John GilmoreJohn GilmoreJohn Gilmore is an American programmer, entrepreneur and civil libertarian, an early employee of Sun Microsystems and a co-founder of the Electronic Frontier Foundation, Cygnus Support and the Cypherpunks; in 1998 he led EFF’s construction of the DES Cracker, which broke DES encryption.Open the full entry, Matthew Green, Susan Landau, Peter G. Neumann and others. An Associated PressAssociated PressThe Associated Press is a cooperative news agency headquartered in New York City. Founded in 1846, it is the oldest and largest news agency in the United States.Open the full entry article of 2016 states that the paper urged the U.S. government to weigh the risks carefully before demanding “back doors” for law enforcement.⁠[19][20]

On March 1, 2016, the Association for Computing Machinery announced that he and Martin E. Hellman had received the 2015 A.M. Turing Award “for critical contributions to modern cryptography”; the award carries a prize of $1 million, with financial support provided by GoogleGoogleGoogle is an American technology company founded by Larry Page and Sergey Brin and incorporated in 1998. It became an Alphabet subsidiary in 2015. Its businesses include internet search, advertising, software platforms, cloud computing, and artificial intelligence.Open the full entry, and was presented at the annual awards banquet in San Francisco on June 11, 2016. The citation on his laureate page begins “For inventing and promulgating both asymmetric public-key cryptography, including its application to digital signatures” and goes on to a practical key-exchange method.⁠[12][1][6]

When the award was announced he was speaking on a panel at the RSA security conference in San Francisco. An Associated Press article gives his age at the time as 71 and quotes him: “What we did was reduce the need to know people before talking to them,” and “I think the people who will control the machines will control the world of the future”; he regarded the dispute between AppleAppleApple is a public technology company founded in 1976 and headquartered in Cupertino, California, United States. Its business includes the iPhone, Mac, iPad, wearables, and services such as digital content, payments, and cloud storage. The company builds its product system through in-house hardware, operating systems, and services.Open the full entry and the Federal Bureau of InvestigationFederal Bureau of InvestigationThe Federal Bureau of Investigation (FBI) is the federal investigative agency of the U.S. Department of Justice. It grew out of a force of special agents organized by Attorney General Charles J. Bonaparte in 1908, has used its present name since 1935 and is headquartered in Washington, D.C.Open the full entry as just one aspect of a larger government effort to gain control.⁠[21][22]

The Stanford Daily wrote on March 2, 2016, that he and Hellman sided with Apple in its dispute with the Federal Bureau of Investigation over unlocking an iPhone connected with the San Bernardino attack, arguing that the precedent could lead to many similar requests or chill free speech; it also states that both men mentor pre- and postdoctoral fellows in cybersecurity at Stanford’s Center for International Security and Cooperation.⁠[23]

On February 8, 2017, the National Academy of Engineering announced that it had elected 84 new members and 22 foreign members. Communications of the ACM listed him among the 17 computer scientists elected, as adviser, Black Ridge Technology, Redwood City, California, honoured “for the invention of public key cryptography and for broader contributions to privacy.”⁠[24][25][13]

The same year he was elected a Fellow of the Royal Society. The Royal Society’s Fellow page states that since leaving Sun he has advised security start-ups, and lists his posts as consulting scholar at Stanford’s Center for International Security and Cooperation, honorary visiting professor at Royal Holloway, University of London, and technical adviser to Cryptomathic Ltd in the United Kingdom.⁠[13]

In May 2018, on the first day of CoinDeskCoinDeskCoinDesk is a cryptocurrency media, events, index, and data company founded in 2013 and headquartered in New York. Its businesses include the CoinDesk news website, the annual crypto industry conference Consensus, and the CoinDesk Indices index business. In November 2023, the digital asset exchange Bullish acquired CoinDesk from Digital Currency Group, and CoinDesk has since operated as an independent subsidiary of Bullish.Open the full entry’s ConsensusConsensusConsensus is an annual cryptocurrency, blockchain, and Web3 industry conference hosted by the crypto media outlet CoinDesk (not the consensus mechanism of a blockchain). It was first held in New York in 2015 and later moved to Austin and Toronto; a Hong Kong edition was added from 2025, and since 2026 the main conference has been held in Miami.Open the full entry 2018 conference, he held a fireside chat with the Zcash founder Zooko WilcoxZooko WilcoxZooko Wilcox is a computer security expert, an early cypherpunk, the founder of the Electric Coin Company (ECC), and the principal initiator of Zcash; his early papers were also signed Zooko Wilcox-O’Hearn. He worked on DigiCash, Mojo Nation, Tahoe-LAFS, and cryptographic software research, and led ECC in bringing Zcash to mainnet in 2016. After stepping down as ECC’s chief executive officer in 2023, he joined Shielded Labs in 2024 as head of product and a board member, and in 2025 was appointed a strategic advisor to Cypherpunk Technologies.Open the full entry. CoinDesk’s article states that he saw the blockchain boom as “another resurgence” of cryptography and a “huge refocus” on its technical side; he said that people had tried for years to build digital money systems and that “nobody succeeded before that,” and when Zooko Wilcox credited Satoshi NakamotoSatoshi NakamotoSatoshi Nakamoto is the pseudonymous creator of Bitcoin, who published the Bitcoin white paper in 2008, released the first Bitcoin software and launched the blockchain in 2009, and stopped public activity around 2011; the person’s true identity has never been confirmed.Open the full entry with sparking the renaissance he joked that they should “get another chair” for Satoshi Nakamoto.⁠[26]

In the conversation he said that he did not see a conflict between business development and political development, and that bringing market forces into protocols could speed up privacy technology, since battle-tested systems should earn higher valuations than vulnerable ones; on decentralization he said that a system without public-key cryptography would depend on an administrative authority, which works for the U.S. military but “won’t work” for an Internet of commerce.⁠[26]

On July 5, 2018, he was appointed a full-time professor at Zhejiang University and honorary director of its Institute of Cyber Security Research, to work with the university and Zhejiang Lab on academic research, international exchanges and the recruitment of overseas professionals, and to teach a course on cybersecurity to graduate students from October; after the appointment ceremony he gave a lecture on the evolution of cryptography in recent years. The university’s president, Wu Zhaohui, said that his findings and hands-on experience would help advance the university’s computer science and information technology programs.⁠[27]

On January 31, 2019, China Daily described him as chief scientist of Cryptic Labs and announced that he would attend the China International Big Data Industry Expo in Guiyang, Guizhou province, on May 26–29, taking part in the opening ceremony and other events and speaking at high-level forums and dialogues.⁠[16]

In March 2019, in an interview with CGTN’s Global Business, he said that blockchain uses many terms and techniques of cryptography but “it is much newer”; it is a young technology and “it’s really impossible to say yet exactly how it would scale,” and it is too early to set standards, which if set too soon could “stifle the development of technology”; he did not regard blockchain as a decentralizing technology, since in his view decentralizing means moving control out of the hands of small numbers of people.⁠[28]

On November 10, 2019, at the 14th Silicon Valley Salon hosted by the government of the Hi-Tech District in Hangzhou, he was appointed honorary dean of the first Hangzhou Turing Award Workstation, which was to work with the local government on cooperation between foundations and the application of scientific achievements.⁠[29]

In 2021 he was interviewed by Tom Rocks Maths at the Heidelberg Laureate Forum about the discovery of public-key cryptography; the Tom Rocks Maths website published the interview on November 21, 2021.⁠[8]

On April 29, 2025, he spoke on the Cryptographers’ Panel at the RSA Conference in San Francisco. The Register’s article states that he called the strategy of collecting encrypted data now and exploiting it later “the heart of intelligence” (“collect-now, exploit-later, is the heart of intelligence”) and said that “There are vast tape libraries at NSA”; he noted that developers were working on hybrid post-quantum cryptography and considered the United Kingdom’s latest attempt to eavesdrop on Apple users largely futile because people have many secure alternatives to iCloud.⁠[30]

Discussing U.S. Defense Secretary Pete HegsethPete HegsethPete Hegseth (born 1980) is an American politician, author and former television host who has been the 29th U.S. secretary of defense since 2025, also styled Secretary of War since September 2025.Open the full entry’s use of Signal for federal work, The Register’s article states that on the panel he deplored the use of Signal in government to get around public-sector records-keeping laws; he also voiced concern that SignalSignalSignal is an end-to-end encrypted messaging app run by a nonprofit organization; built on the open-source Signal Protocol, it offers text messaging, voice calls and other features, and its client and server code is publicly released.Open the full entry requires updates every few days, saying that someone with a court order could have a bug slipped into a version.⁠[30]

His wife is Mary Fischer; the dedication of the 2007 updated edition of Privacy on the Line, written with Susan Landau, reads: “This book is dedicated to our spouses, Mary Fischer and Neil Immerman.”⁠[15]

In the 1992 interview he said that he had always worked on what interested him, was poor at assignment-driven work, and could not separate intellectual curiosity from professional commitment; he held that one of the things that characterizes good intellectual work is a certain self-importance, the understanding that the intellect matters and that you matter.⁠[3]

The Association for Computing Machinery biography states that he and Hellman wrote early critiques of the Data Encryption Standard (DES). In the 1992 interview he said that the National Security Agency faced a dilemma over DES, since the standard could not be both secure enough for government use and easy for intelligence services to break: “I did not understand how those people dared either standardize a secure system or standardize a non-secure system.”⁠[1][3]

The Stanford Daily writes that he and Hellman challenged the National Security Agency’s near-monopoly on cryptographic research and that the agency tried to limit the distribution of their work, but the two kept publishing; an Associated Press article states that their work drew the attention of the National Security Agency, which tried to contain the technology in what became known as the first “crypto war.”⁠[23][22]

The Association for Computing Machinery biography states that James Ellis of GCHQ conceived the idea around 1969–1970 and that Clifford Cocks devised an algorithm in 1973, and that a former director of the National Security Agency said two-key cryptography had been discovered at the agency about a decade earlier; the biography argues that it was open research that drove the practical advances. It also states that Hellman later argued that “public-key credit should be to Diffie-Hellman-Merkle.”⁠[1]

The same biography states that Ronald Rivest, Adi Shamir and Leonard Adleman developed the RSA algorithm in 1977 and later shared the 2002 A.M. Turing Award. In the 1992 interview he said that Bill Mann had earlier put forward what would now be called a trapdoor one-way function, though neither Mann nor their group recognized it at the time and he found it later in his notes; that Peter Deutsch sent him a message in 1976 or 1977 asking what was known about cryptosystems with the public-key property; that had they not made the discovery, somebody else would have within a very short time; and that public-key cryptography moved much faster than he had expected, becoming a mainstay sooner than he had thought, and that he was surprised RSA had no competitor.⁠[1][3]

Satoshi Nakamoto’s BitcoinBitcoinBitcoin (common symbol BTC) is an open peer-to-peer electronic cash protocol, network, and native digital asset. Full nodes independently verify transactions and blocks according to the consensus rules; transactions are recorded as UTXOs, and blocks are organized into a public ledger through proof of work. Bitcoin is not issued or managed by any single institution, but using, holding in custody, and trading it still involve key, privacy, market, and legal risks.Open the full entry white paper, “Bitcoin: A Peer-to-Peer Electronic Cash System,” states: “We define an electronic coin as a chain of digital signatures.” Each owner transfers the coin to the next by digitally signing a hash of the previous transaction and the public key of the next owner.⁠[31]

CoinDesk’s article of 2018 states that the 1976 paper he co-wrote laid the foundations of public-key cryptography, which is central to modern Internet security and to cryptocurrencies; it also states that his work has focused more on securing communications than on financial transactions.⁠[26]

Center for International Security and Cooperation: Official website: https://cisac.fsi.stanford.edu/ (opens in a new window).⁠[9]