Leonard Max Adleman | Biography

Leonard Adleman is best known in the field of computing for his work on the development of the RSA system for data encryption (cryptography). He also created a system for calculating with prime numbers, developed a DNA computer, and saw the birth of the computer virus.

Leonard Max Adleman was born in San Francisco in 1945. After receiving schooling in the local area, Adleman went to the University of California at Berkeley to study for his undergraduate degree in mathematics. This was not his first choice for an academic career--he initially wanted to become a chemist, then a medical doctor, before finally settling upon mathematics. He was awarded a Bachelor of Science degree in 1968. After graduation Adleman spent a period of time working as a programmer for the Bank of America before attending San Francisco State College, where he briefly studied physics. He then returned to the University of California at Berkeley where he undertook a Ph.D. in Computer Science. He was awarded this degree in 1976 and wrote a thesis a entitled Number Theoretic Aspects of Computational Complexity.

Upon completion of his graduate studies Adleman took a position at the Massachusetts Institute of Technology (MIT) in the mathematics department. Initially he was hired as an Instructor, becoming an Assistant Professor in 1977, and finally, in 1979, was promoted to Associate Professor. In 1980 Adleman moved to a position at the University of Southern California with the Computer Science Faculty, a position he still retained in 2001. Initially working as an Associate Professor (with tenure), Adleman was made a full Professor in 1983, then in 1985 became the Henry Salvatori Professor of Computer Science. He is also a professor in the molecular biology department.

During all of his career one of Adleman's main areas of interest and research has been in theoretical computer science, particularly the complexity of number theoretical problems, which led to some of his most famous work in the field of cryptography. He was one of the developers, along with Ronald L. Rivest and Adi Shamir, of the RSA system of data encryption. This encryption algorithm was devised in 1976 by the three workers at MIT. It employs an encryption system using one-way functions--mathematical formulae which are simple to compute but almost impossible to reverse. The original system was devised by Rivest and Shamir with Adleman being enlisted to find faults in the system and crack the encryption. He did this 42 times, with some codes requiring only a few minutes work. However, on his 43rd attempt Adleman realized he could not break the system based on prime numbers unless he devoted several years work to the problem--this was felt to be a sufficient level of encryption. The code was patented as the RSA system and together the three men founded RSA Data Security Incorporated, based in California. The patent of the code was subsequently transferred to MIT.

Adleman is also interested in molecular biology and was one of the first people to actually solve a mathematical problem using DNA--specifically he realized that enzymes read DNA in the same manner that the Turing machine proposed by Alan Turing in the 1930s reads digital information stored on a magnetic tape. He encoded strands of DNA to represent the traveling salesman problem, whereby the most efficient route between several cities has to be calculated. The problem was solved by the DNA computer in seconds. Due to the nature of DNA, the potential exists to solve vast problems very quickly. Much research needs to be carried out before there is a truly workable system, though Adleman has a patent pending on molecular computing as of 2001.

Adleman is regarded as the person who coined the term "computer virus" after encountering one built by Fred Cohen, a student of his, in 1983. Cohen and Adleman decided to publish the code for this virus, reasoning that it was the job of a university to produce and disseminate information. Adleman felt that computer viruses could open up many new possibilities, and that their nuisance value could potentially be outweighed by the good that may come from the technology in the future.

As a result of his interest in molecular biology, Adleman produced a mathematical model of the immune deficiency caused by the AIDS virus. This provided insight into how the virus works and also opened up various avenues of research toward finding a cure. Adleman also wrote a new method for establishing whether a number is prime (the piece of work he is most proud of).

Adleman has received a number of awards, including in 2000 the IEEE Kobayashi Award for Computers and Communications (jointly with Rivest and Shamir) and the 1996 Association of Computing Machinery (ACM) Paris Kanallakis Award for Theory and Practice. Adleman has published over 60 scientific papers and holds two computing patents.

At the start of the twenty-first century Adleman was still employed at USC where he continues his work on number complexity and HIV. He lives in Los Angeles with his wife, with whom he has three children. As well as his computing work, Adleman was the mathematical consultant on the Hollywood film Sneakers, which dealt with cryptography.