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Ralph Merkle

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Ralph Merkle
Merkle in 2007
Born (1952-02-02) February 2, 1952 (age 74)
Berkeley, California, United States
Education
Known for
Spouse
​
(m. 1983)​
AwardsIEEE Richard W. Hamming Medal (2010)
Computer History Museum Fellow (2011)[1]
Scientific career
FieldsPublic-key cryptography, cryonics
Institutions
ThesisSecrecy, authentication and public key systems
Martin Hellman
Websitewww.ralphmerkle.com

Ralph C. Merkle (born February 2, 1952) is an American computer scientist. He co-invented public-key cryptography and invented cryptographic hashing, and has worked on molecular nanotechnology and cryonics.

As an undergraduate at the University of California, Berkeley, Merkle devised Merkle's Puzzles, an early scheme for public-key key exchange. He completed his Ph.D. at Stanford University in 1979 under Martin Hellman, with whom he co-invented the Merkle–Hellman knapsack cryptosystem. He later introduced the Merkle–Damgård construction, which underlies many cryptographic hash algorithms, and Merkle trees, which are widely used in distributed systems. Merkle held research positions at Xerox PARC and Zyvex and was a Distinguished Professor at the Georgia Institute of Technology; he is a senior research fellow at the Institute for Molecular Manufacturing and a board member of the Alcor Life Extension Foundation. He received the IEEE Richard W. Hamming Medal in 2010 and was inducted into the National Inventors Hall of Fame in 2011.

Early life and education

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Merkle graduated from Livermore High School in Livermore, California in 1970.[3] He received a B.A. in Computer Science from the University of California, Berkeley in 1974 and an M.S. in Computer Science from the same institution in 1977, with a thesis titled "Evaluators for Attribute Grammars".[3] He received a Ph.D. in Electrical Engineering from Stanford University on June 17, 1979, with the thesis "Secrecy, Authentication, and Public Key Systems".[3][4]

Research

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Early work and Merkle's Puzzles

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As an undergraduate at UC Berkeley, Merkle developed a scheme that would allow two parties to communicate securely over an insecure channel without first sharing a secret key. He submitted the work as a course project, and after the course continued refining the idea on his own.[5] The scheme, later named Merkle's Puzzles, was first described in a manuscript Merkle submitted in 1975 and published in 1978 in Communications of the ACM.[6]

In the scheme, the sender generates a large set of encrypted "puzzles" and transmits them; the receiver chooses one at random, solves it, and uses the contained value as a shared key. An eavesdropper unable to distinguish the chosen puzzle must, on average, solve half the set, producing a quadratic gap in work between legitimate parties and attackers.[6]

Merkle's manuscript circulated while Whitfield Diffie and Martin Hellman were preparing the 1976 paper "New Directions in Cryptography", which formalized the public-key paradigm and credited Merkle's puzzles as a precursor.[7] Merkle entered graduate study at Stanford under Hellman, and the two co-authored the Merkle–Hellman knapsack cryptosystem, one of the earliest concrete public-key encryption schemes.[8] Merkle's 1979 Stanford doctoral thesis collected this body of work.[4]

Hashing, signatures, and ciphers

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Binary tree diagram with leaf-level hashes labeled L1 through L4 and parent nodes containing concatenated hashes
A Merkle tree, used to authenticate large data sets by hashing data in pairs up to a single root hash

Merkle invented cryptographic hashing, formalized as the Merkle–Damgård construction in a pair of articles published a decade later, and introduced Merkle trees as a method for efficiently authenticating large data sets. The Merkle–Damgård construction underlies many subsequent hashing algorithms.[9]

At Xerox PARC, Merkle designed the Khufu and Khafre block ciphers[10] and the Snefru hash function.[11]

Career

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Merkle managed compiler development at Elxsi from 1980.[12] In 1988, he became a research scientist at Xerox PARC.[12] In 1999, he became a nanotechnology theorist at Zyvex.[12] In 2003, he was named a Distinguished Professor at Georgia Tech, where he led the Georgia Tech Information Security Center.[13] In 2006, he returned to the San Francisco Bay Area, where he is a senior research fellow at the Institute for Molecular Manufacturing, a faculty member at Singularity University, and a board member of the Alcor Life Extension Foundation.[12]

He has published works on molecular manipulation and self-replicating machines.[14] Merkle appears in the science fiction novel The Diamond Age, which involves nanotechnology.

Personal life

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Merkle is the son of Theodore Charles Merkle, director of Project Pluto, and the brother of historical novelist Judith Merkle Riley. He is a grandnephew of baseball player Fred Merkle.[12] He is married to video game designer Carol Shaw, known for the 1982 Atari 2600 game River Raid.[12]

Awards

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Selected publications

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  • Merkle, Ralph C. (April 1978). "Secure communications over insecure channels". Communications of the ACM. 21 (4): 294–299. doi:10.1145/359460.359473.
  • Merkle, Ralph C.; Hellman, Martin E. (September 1978). "Hiding information and signatures in trapdoor knapsacks". IEEE Transactions on Information Theory. 24 (5): 525–530. doi:10.1109/TIT.1978.1055927.
  • Merkle, Ralph C. (June 1979). Secrecy, Authentication, and Public Key Systems (PDF) (PhD). Stanford University.
  • Merkle, Ralph C. (1990). "One way hash functions and DES". Advances in Cryptology – CRYPTO '89 Proceedings. Lecture Notes in Computer Science. Vol. 435. Springer. pp. 428–446. doi:10.1007/0-387-34805-0_40. ISBN 978-0-387-97317-3.
  • Merkle, Ralph C. (1990). "A certified digital signature". Advances in Cryptology – CRYPTO '89 Proceedings. Lecture Notes in Computer Science. Vol. 435. Springer. pp. 218–238. doi:10.1007/0-387-34805-0_21. ISBN 978-0-387-97317-3.
  • Merkle, Ralph C. (1990). "A fast software one-way hash function". Journal of Cryptology. 3 (1): 43–58. doi:10.1007/BF00203968.
  • Merkle, Ralph C. (1991). "Fast software encryption functions". Advances in Cryptology – CRYPTO '90. Lecture Notes in Computer Science. Vol. 537. Springer. pp. 476–501. doi:10.1007/3-540-38424-3_34. ISBN 978-3-540-54508-8.

References

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  1. ^ "Ralph Merkle 2011 Fellow". Computer History Museum. Archived from the original on January 3, 2013.
  2. ^ Merkle, R. C. (1988). "A Digital Signature Based on a Conventional Encryption Function". Advances in Cryptology – CRYPTO '87. Lecture Notes in Computer Science. Vol. 293. pp. 369–378. doi:10.1007/3-540-48184-2_32. ISBN 978-3-540-18796-7.
  3. ^ a b c Merkle, Ralph C. "Merkle Education and Work". ralphmerkle.com. Retrieved May 11, 2026.
  4. ^ a b Merkle, Ralph C. (June 1979). Secrecy, Authentication, and Public Key Systems (PDF) (PhD). Stanford University.
  5. ^ Garfinkel, Simson (1994). Pretty Good Privacy. O'Reilly.[page needed]
  6. ^ a b Merkle, Ralph C. (April 1978). "Secure communications over insecure channels". Communications of the ACM. 21 (4): 294–299. doi:10.1145/359460.359473.
  7. ^ Diffie, Whitfield; Hellman, Martin E. (November 1976). "New directions in cryptography". IEEE Transactions on Information Theory. 22 (6): 644–654. doi:10.1109/TIT.1976.1055638.
  8. ^ Merkle, Ralph C.; Hellman, Martin E. (September 1978). "Hiding information and signatures in trapdoor knapsacks". IEEE Transactions on Information Theory. 24 (5): 525–530. doi:10.1109/TIT.1978.1055927.
  9. ^ Mironov, Ilya. "Hash Functions: From Merkle–Damgård to Shoup" (PDF). Stanford University.
  10. ^ Merkle, Ralph C. (1991). "Fast Software Encryption Functions". Advances in Cryptology – CRYPTO '90. Lecture Notes in Computer Science. Vol. 537. Springer. pp. 476–501. doi:10.1007/3-540-38424-3_34. ISBN 978-3-540-54508-8.
  11. ^ Merkle, Ralph C. (1990). "A Fast Software One-Way Hash Function". Journal of Cryptology. 3 (1): 43–58. doi:10.1007/BF00203968.
  12. ^ a b c d e f "Ralph C. Merkle". ralphmerkle.com. Retrieved November 25, 2013. My wife is Carol Shaw. My sister, Judith Merkle Riley, wrote historical novels. My father, Theodore Charles Merkle, ran Project Pluto. My great uncle was Fred Merkle, of baseball fame.
  13. ^ "Cybersecurity Pioneer Selected to Lead Information Security Center at Georgia Tech" (Press release). Georgia Institute of Technology. July 15, 2003. Archived from the original on September 5, 2006. Retrieved March 17, 2007.
  14. ^ Merkle, Ralph; Freitas, Robert (2004). Kinematic Self-Replicating Machines. Landes Bioscience. ISBN 1570596905.
  15. ^ "Ralph Merkle – Award Winner". ACM. Archived from the original on April 2, 2013. Retrieved November 25, 2013.
  16. ^ "1998 Feynman Prize in Nanotechnology". Foresight.org. September 4, 1998. Archived from the original on October 23, 2013. Retrieved November 25, 2013.
  17. ^ "Koji Kobayashi Computers and Communications Award". IEEE. Archived from the original on January 13, 2013. Retrieved November 25, 2013.
  18. ^ "Ralph Merkle, IACR Fellow". Iacr.org. 2008. Retrieved November 25, 2013.
  19. ^ "CISAC's scholars awarded for invention of public-key cryptography". Stanford University. December 9, 2009. Retrieved November 25, 2013.
  20. ^ "Computer History Museum Fellow Awards: Ralph Merkle". Computer History Museum. Archived from the original on October 23, 2013. Retrieved November 25, 2013.
  21. ^ "Hall of Fame Induction: 2011 Inductees". Invent.org. Archived from the original on December 26, 2013. Retrieved November 25, 2013.
  22. ^ "The Levchin Prize for Real-World Cryptography". Real World Crypto Symposium. International Association for Cryptologic Research. Retrieved April 9, 2024.

Further reading

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