# Manuel Blum

## University Professor Emeritus

**Address:**

5013 GHC

Computer Science Department

Carnegie Mellon University

5000 Forbes Avenue

Pittsburgh, PA 15213

**P:** 412-268-3742

# Education

Ph.D., Massachusetts Institute of Technology

# Research

Peekaboom: A Game for Locating Objects in Images Luis von Ahn, Ruoran Liu and Manuel Blum.

Improving Accessibility of the Web with a Computer Game Luis von Ahn, S. Ginosar, M. Kedia, R. Liu and M. Blum.

Verbosity: A Game for Collecting Common-Sense Facts Luis von Ahn, Mihir Kedia and Manuel Blum.

Toward a High-level Definition of Consciousness Manuel Blum, Ryan Williams Brendan Juba, Matt Humphrey.

Mathematical Foundations for Understanding and Designing Conceptualizing Strategizing Control Systems

Telling Humans and Computers Apart Automatically: How Lazy Cryptographers do AI Luis von Ahn, Manuel Blum and John Langford.

CAPTCHA: Using Hard AI Problems for Security Luis von Ahn, Manuel Blum, Nicholas J. Hopper, John Langford.

On the complexity of MAX / MIN / AVRG Circuits (with Rachel Rue, Ke Yang). 2002.

Telling Humans and Computers Apart (Automatically) (with Luis von Ahn, John Langford ). 2002.

Secure Human Identification Protocols (with Nicholas J. Hopper).

A Secure Human-Computer Authentication Scheme (with Nicholas J. Hopper).2000.

Software Reliability via Run-Time Result-Checking (with H. Wasserman).

Preliminary version: Program Result-Checking: A Theory of Testing Meets a Test of Theory,

*To Appear in ACM CHI 2006*(pdf)Improving Accessibility of the Web with a Computer Game Luis von Ahn, S. Ginosar, M. Kedia, R. Liu and M. Blum.

*To Appear in ACM CHI Notes 2006*(pdf)Verbosity: A Game for Collecting Common-Sense Facts Luis von Ahn, Mihir Kedia and Manuel Blum.

*To Appear in ACM CHI Notes 2006*(pdf)Toward a High-level Definition of Consciousness Manuel Blum, Ryan Williams Brendan Juba, Matt Humphrey.

*Invited Talk to the Annual IEEE Computational Complexity Conference , San Jose CA, (June 2005)*(ppt)Mathematical Foundations for Understanding and Designing Conceptualizing Strategizing Control Systems

*(NSF ITR proposal)*(pdf)Telling Humans and Computers Apart Automatically: How Lazy Cryptographers do AI Luis von Ahn, Manuel Blum and John Langford.

*In Communications of the ACM, Feb. 2004.*PDFCAPTCHA: Using Hard AI Problems for Security Luis von Ahn, Manuel Blum, Nicholas J. Hopper, John Langford.

*In Eurocrypt 2003*PDF / PSOn the complexity of MAX / MIN / AVRG Circuits (with Rachel Rue, Ke Yang). 2002.

*CMU SCS Technical Report, CMU-CS-02-110*PDF / absTelling Humans and Computers Apart (Automatically) (with Luis von Ahn, John Langford ). 2002.

*CMU Tech Report*PDFSecure Human Identification Protocols (with Nicholas J. Hopper).

*Advances in Crypotology, Proceedings of Asiacrypt 2001, December 2001: 52-66*A Secure Human-Computer Authentication Scheme (with Nicholas J. Hopper).2000.

*CMU-CS-00-139 May 2000*PDF / absSoftware Reliability via Run-Time Result-Checking (with H. Wasserman).

*Journal of the ACM.*Preliminary version: Program Result-Checking: A Theory of Testing Meets a Test of Theory,

*Proc. 35th IEEE FOCS, 1994, pp. 382-392.*PDF / PS
Reflections on the Pentium Division Bug (with H. Wasserman).

Preliminary version:

Self-testing/correcting with applications to numerical problems (with Michael Luby, Ronitt Rubinfeld).

Self-Testing/Correcting with Applications to Numerical Problems (with M. Luby and R. Rubinfeld),

Designing programs that check their work (with Sampath Kannan)

Non-interactive zero-knowledge and its applications (extended abstract).(with Paul Feldman, and Silvio Micali)

A Simple Unpredictable Pseudo-Random Number Generator (with Lenore Blum, Mike Shub).

How to Generate Cryptographically Strong Sequences of Pseudo-Random Bits. (with Silvio Micali).

How to exchange (secret) keys (extended abstract).

Coin Flipping by Telephone.

On the Power of the Compass (or, Why Mazes are Easier to Search Than Graphs) (with D. Kozen), Proc. IEEE FOCS Conf., 1978, pp. 132-142.

Toward a Mathematical Theory of Inductive Inference (with L. Blum),

Linear time bounds for median computations (with Robert W. Floyd, Vaughan Pratt, Ronald L. Rivest, Robert E. Tarjan).

Linear Time Bounds for Median Computations (with Floyd, Pratt, Rivest, and Tarjan).

On effective procedures for speeding up algorithms

A Machine-Independent Theory of the Complexity of Recursive Functions.

*IEEE Transactions on Computers, vol. 45, no. 4, April 1996, pp. 385-393.*Preliminary version:

*Proc. 8th Int'l Software Quality Week, 1995*. PDF / PSSelf-testing/correcting with applications to numerical problems (with Michael Luby, Ronitt Rubinfeld).

*In Proceedings of the TwentySecond Annual ACM Symposium on Theory of Computing, pages 73-83, Baltimore, Maryland, 14-16 May 1990.*Self-Testing/Correcting with Applications to Numerical Problems (with M. Luby and R. Rubinfeld),

*STOC, 1990, p. 10*.Designing programs that check their work (with Sampath Kannan)

*In Proceedings of the Twenty First Annual ACM Symposium on Theory of Computing, pages 86-97, Seattle, Washington, 15-17 May 1989.*Non-interactive zero-knowledge and its applications (extended abstract).(with Paul Feldman, and Silvio Micali)

*In Proceedings of the Twentieth Annual ACM Symposium on Theory of Computing, pages 103-112, Chicago, Illinois, 2-4 May 1988.*A Simple Unpredictable Pseudo-Random Number Generator (with Lenore Blum, Mike Shub).

*SIAM J. Comput. 15(2): 364-383 (1986)*How to Generate Cryptographically Strong Sequences of Pseudo-Random Bits. (with Silvio Micali).

*SIAM J. Comput. 13(4): 850-864 (1984)*How to exchange (secret) keys (extended abstract).

*In Proceedings of the Fifteenth Annual ACM Symposium on Theory of Computing, pages 440-447, Boston, Massachusetts, 25-27 April 1983.*Coin Flipping by Telephone.

*CRYPTO 1981: 11-15*HTMLOn the Power of the Compass (or, Why Mazes are Easier to Search Than Graphs) (with D. Kozen), Proc. IEEE FOCS Conf., 1978, pp. 132-142.

Toward a Mathematical Theory of Inductive Inference (with L. Blum),

*Information and Control, Vol. 28, No. 2, 1975, pp. 125-155.*Linear time bounds for median computations (with Robert W. Floyd, Vaughan Pratt, Ronald L. Rivest, Robert E. Tarjan).

*In Conference Record, Fourth Annual ACM Symposium on Theory of Computing, pages 119-124, Denver, Colorado, 1-3 May 1972.*Linear Time Bounds for Median Computations (with Floyd, Pratt, Rivest, and Tarjan).

*Proc. 4th Annual ACM Symposium on Theory of Computing, 1972, pp. 119-124.*On effective procedures for speeding up algorithms

*In Conference Record of ACM Symposium on Theory of Computing, pages 43-53, Marina del Rey, California, 5-7 May 1969.*A Machine-Independent Theory of the Complexity of Recursive Functions.

*J. ACM, XIV, No. 2, 1967, pp. 322-336.*