Robert Morris (cryptographer)

Robert "Bob" H. Morris is an American cryptographer. He received a bachelor's degree in mathematics from Harvard University in 1957 and a master's degree in mathematics from Harvard in 1958. He was a researcher at Bell Labs from 1960 until 1986, when he began work at the National Security Agency (NSA). 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. He is the father of Robert Tappan Morris, who wrote the (in)famous 1988 Morris Worm.

Morris contributed to early versions of UNIX. He wrote the math library, the program crypt, and the password encryption scheme used for user authentication. The encryption scheme 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.

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.


  • Never underestimate the attention, risk, money and time that an opponent will put into reading traffic.
  • Rule 1 of cryptanalysis: check for plaintext.
  • The three golden rules to ensure computer security are: do not own a computer; do not power it on; and do not use it.

Selected publications

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

External links

  • Dennis Ritchie's "Dabbling in the Cryptographic World" tells the story of cryptographic research he performed with Morris, and why that research was never published.


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