Don Coppersmith

{{short description|American mathematician (born 1950)}}

{{Infobox scientist

| name = Don Coppersmith

| image =

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| caption =

| birth_date = {{Birth year and age|1950}}

| birth_place =

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| nationality = American

| fields = Cryptography

| workplaces = IBM, IDA/CCRP

| alma_mater = Massachusetts Institute of Technology (B.S., 1972)
Harvard University (M.S., 1975; Ph.D., 1977)

| thesis_title = Deformations of Lie Groups and Lie Algebras

| thesis_url =

| thesis_year = 1977

| doctoral_advisor = John H. Hubbard
Shlomo Sternberg

| doctoral_students =

| known_for = Coppersmith–Winograd algorithm

| awards = RSA Award for Excellence in Mathematics

}}

Don Coppersmith (born {{abbr|c.|circa}} 1950) is a cryptographer and mathematician. He was involved in the design of the Data Encryption Standard block cipher at IBM, particularly the design of the S-boxes, strengthening them against differential cryptanalysis.{{cite journal

| last = Coppersmith

| first = Don

| date = May 1994

| title = The Data Encryption Standard (DES) and its strength against attacks

| journal = IBM Journal of Research and Development

| volume = 38

| issue = 3

| pages = 243–250

| url = http://www.research.ibm.com/journal/rd/383/coppersmith.pdf

| doi = 10.1147/rd.383.0243

| archive-url = https://web.archive.org/web/20090325034256/http://www.research.ibm.com/journal/rd/383/coppersmith.pdf

| archive-date = 2009-03-25

}}

He also improved the quantum Fourier transform discovered by Peter Shor in the same year (1994).{{cite journal

| last = Coppersmith

| first = D.

| date = 1994

| title = An approximate Fourier transform useful in quantum factoring.

| journal = Technical Report RC19642, IBM

}}

He has also worked on algorithms for computing discrete logarithms, the cryptanalysis of RSA, methods for rapid matrix multiplication (see Coppersmith–Winograd algorithm) and IBM's MARS cipher. He is also a co-designer of the SEAL and Scream ciphers.

In 1972, Coppersmith obtained a bachelor's degree in mathematics at the Massachusetts Institute of Technology, and a Masters and Ph.D. in mathematics from Harvard University in 1975 and 1977 respectively. He was a Putnam Fellow each year from 1968–1971, becoming the first four-time Putnam Fellow in history.{{cite web|title=Putnam Competition Individual and Team Winners |url=http://www.maa.org/programs/maa-awards/putnam-competition-individual-and-team-winners |publisher=Mathematical Association of America|access-date=December 13, 2021}} In 1998, he started Ponder This, an online monthly column on mathematical puzzles and problems. In October 2005, the column was taken over by James Shearer.{{cite web

| url=https://www.research.ibm.com/haifa/ponderthis/index.shtml

| title=Welcome to our monthly puzzles

| quote=The current puzzlemaster is Oded Margalit. He took over from James B. Shearer, who took over from the original puzzlemaster Don Coppersmith, in October 2005.

| access-date=2018-01-05}} Around that same time, he left IBM and began working at the IDA Center for Communications Research, Princeton.

{{cite journal

| last1=Coppersmith

| first1= Don

| last2 = Wu

| first2 = Chai Wah

| title = Conditions for weak ergodicity of inhomogeneous Markov chains

| journal = Statistics & Probability Letters

| volume = 78

| pages = 3082–3085

| date = 2008-12-01

| issue= 17

| doi= 10.1016/j.spl.2008.05.012}}

In 2002, Coppersmith won the RSA Award for Excellence in Mathematics.{{cite web

| title=Don Coppersmith Wins RSA Security Award for Mathematics

| url=https://www-03.ibm.com/press/us/en/pressrelease/22019.wss

| date=2002-02-19

| archive-url=https://web.archive.org/web/20170127070459/https://www-03.ibm.com/press/us/en/pressrelease/22019.wss

| access-date=2018-01-05| archive-date=2017-01-27

}}{{cite web

| title=RSA Security Announces 2002 Award Recipients; Awards Recognize Major Contributions in Mathematics, Public Policy and Industry

| url=https://www.prnewswire.com/news-releases/rsa-security-announces-2002-award-recipients-awards-recognize-major-contributions-in-mathematics-public-policy-and-industry-76070627.html

| date=2002-02-19

| archive-url=https://web.archive.org/web/20180105233623/https://www.prnewswire.com/news-releases/rsa-security-announces-2002-award-recipients-awards-recognize-major-contributions-in-mathematics-public-policy-and-industry-76070627.html

| access-date=2018-01-05| archive-date=2018-01-05

}}

In 2022, Coppersmith was awarded the Levchin Prize for “foundational innovations in cryptanalysis”{{cite web |title=The Levchin Prize for Real-World Cryptography |url=https://rwc.iacr.org/LevchinPrize/winners.html |website=Real World Crypto Symposium |publisher=International Association for Cryptologic Research |access-date=9 April 2024}}

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