Robert Morris (cryptographer)

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Robert H. Morris Sr.
Born(1932-07-25)July 25, 1932[1]
DiedJune 26, 2011(2011-06-26) (aged 78)[1]
Alma materHarvard University[1]
Known forMultics, Unix
SpouseAnne Farlow Morris
ChildrenRobert Tappan Morris, Meredith Morris, Benjamin Morris
Scientific career
FieldsMathematics, cryptography
InstitutionsNational Security Agency, Bell Labs[1]

Robert H. Morris Sr. (July 25, 1932 – June 26, 2011) was an American cryptographer and computer scientist.[1][2]

Family and education[edit]

Morris was born in Boston, Massachusetts. His parents were Walter W. Morris, a salesman, and Helen Kelly Morris, a homemaker.[1] He received a bachelor's degree in mathematics from Harvard University in 1957 and a master's degree in applied mathematics from Harvard in 1958.

He married Anne Farlow, and they had three children together: Robert Tappan Morris (author of the 1988 Morris worm),[3] Meredith Morris, and Benjamin Morris.[4]

Bell Labs[edit]

From 1960 until 1986, Morris was a researcher at Bell Labs and worked on Multics and later Unix.

Together with Douglas McIlroy, he created M6 macro processor in FORTRAN IV, which was later ported to Unix.[5]

Using the TMG compiler-compiler, Morris, together with McIlroy, developed the early implementation of PL/I compiler called EPL for Multics project.[6][7] The pair also contributed a version of runoff text-formatting program for Multics.[8]

Morris's contributions to early versions of Unix include the math library, the dc programming language, the program crypt, and the password encryption scheme used for user authentication.[9][10] The encryption scheme (invented by Roger Needham), was based on using a trapdoor function (now called a key derivation function) to compute hashes of user passwords which were stored in the file /etc/passwd; analogous techniques, relying on different functions, are still in use today.[11]

National Security Agency[edit]

In 1986, Morris began work at the National Security Agency (NSA).[1] He served as chief scientist of the NSA's National Computer Security Center, where he was involved in the production of the Rainbow Series of computer security standards, and retired from the NSA in 1994.[12][13][14] He once told a reporter that, while at the NSA, he helped the FBI decode encrypted evidence.[1]

There is a description of Morris in Clifford Stoll's book The Cuckoo's Egg. Many readers of Stoll's book remember Morris for giving Stoll a challenging mathematical puzzle (originally due to John H. Conway) in the course of their discussions on computer security: What is the next number in the sequence 1 11 21 1211 111221? (known as the look-and-say sequence). Stoll chose not to include the answer to this puzzle in The Cuckoo's Egg, to the frustration of many readers.[15]

Robert Morris died in Lebanon, New Hampshire.


  • Rule 1 of cryptanalysis: check for plaintext.[16]
  • Never underestimate the attention, risk, money, and time that an opponent will put into reading traffic.[16]
  • It is easy to run a secure computer system. You merely have to disconnect all dial-up connections and permit only direct-wired terminals, put the machine and its terminals in a shielded room, and post a guard at the door.[17]

Selected publications[edit]

  • (with Fred T. Grampp) UNIX Operating System Security, AT&T Bell Laboratories Technical Journal, 63, part 2, #8 (October 1984), pp. 1649–1672.


  1. ^ a b c d e f g h i Markoff, John (29 June 2011). "Robert Morris, Pioneer in Computer Security, Dies at 78". The New York Times. Retrieved 30 June 2011.
  2. ^ 4th UNIX Security Symposium. USENIX. 1993.
  3. ^ United States v. Morris (1991), 928 F.2d 504, 505 (2d Cir. 1991).
  4. ^ Robert Morris obituary, The Washington Post, June 30, 2011.
  5. ^ Cole, A. J. (1981). Macro Processors (2nd, revised ed.). CUP Archive. p. 254.
  6. ^ R. A. Frieburghouse. "The Multics PL/1 Compiler".
  7. ^ Tom Van Vleck (ed.). "The Choice of PL/I".
  8. ^ "Multics Features".
  9. ^ McIlroy, M. D. (1987). A Research Unix reader: annotated excerpts from the Programmer's Manual, 1971–1986 (PDF) (Technical report). CSTR. Bell Labs. 139.
  10. ^ Dabbling in the Cryptographic World--A Story, Dennis Ritchie, May 5, 2000, Bell Labs. Archived.
  11. ^ Password Security: A Case History by Robert Morris and Ken Thompson (1978)
  12. ^ The data encryption standard—Retrospective and prospects, R. Morris, IEEE Communications 16, #6 (November 1978), pp. 11–14.
  13. ^ IEEE Electronic CIPHER 9 (1995-09-18)
  14. ^ AUUG 98 Conference Information and Registration Form, accessed on line November 29, 2007.
  15. ^ "FAQ about Morris Number Sequence". Archived from the original on June 6, 1997.
  16. ^ a b Gillogly, Jim (2 September 1995). "Notes on Crypto '95: Non-cryptographic Ways of Losing Information invited talk by R. Morris". Google Groups. Retrieved 2 August 2023.
  17. ^ Grampp, F. T.; Morris, R. H. (1984). "The UNIX System: UNIX Operating System Security". AT&T Bell Laboratories Technical Journal. 63 (8): 1649–1672. doi:10.1002/j.1538-7305.1984.tb00058.x. S2CID 26877484.

External links[edit]