


Digital  Mark Manasse is master of numbers game
{The Boston Globe, 23Jun90, p. 12}
For the past three months, Mark Manasse of Digital spent most of his time running a worldwide numbers game  and last week he hit the jackpot.
Manasse isn't some shady character mixed up in illegal gambling. He is a computer scientist who, along with a partner, recently created an ad hoc network of more than 1,000 computers across the globe to crack the toughest problem in factoring  a corner of the mathematics world that focuses on breaking down big numbers into smaller ones that can't be divided any further.
Their feat: factoring a 155digit number, known as the ninth Fermat, that has topped factoring specialists' "10 Most Wanted List" since 1983. The number was about 50 digits longer than the largest number previously factored, and marked a breakthrough in the field. Manasse and his partner, Arjen Lenstra from Bellcore Inc. in Morristown, N.J., are now the talk of the math world.
But their project should also interest some in computer circles. That's because the route they took to crack the ninth Fermat is a concrete demonstration of the power of distributed computing: a growing trend in which hundreds of desktop computers are used to tackle a job previously handled by a big mainframe or supercomputer.
Manasse says mainframes and supercomputers aren't equipped to do the particular style of massive number crunching needed to factor large numbers. But since there were not enough engineering workstations at the Palo Alto research center and Bellcore to attack the problem, the pair posted a "help wanted" notice on several electronic bulletin boards, including those at Digital.
A mathematician by training (Harvard undergrad, masters and doctorate from the University of Wisconsin), the 32yearold Manasse is paid by Digital's systems research center in Palo Alto, Calif., to explore factoring. Why? Because big numbers that are hard to factor play an important role in encoding sensitive information before it is sent out over computer networks. Digital, the world's secondlargest computer maker, is keenly interested in keeping computer conversations secret.
The number:
13,407,807,929,942,597,099,574,024,
998,205,846,127,479,365,820,592,393,
377,723,561,443,721,764,030,073,546,
976,801,874,298,166,903,427,690,031,
858,186,486,050,853,753,882,811,946,
569,946,433,649,006,084,097
=
2,424,833
x
7,455,602,825,647,884,208,337,395,
736,200,454,918,783,366,342,657
x
741,640,062,627,530,801,524,787,
141,901,937,474,059,940,781,097,
519,023,905,821,316,144,415,759,
504,705,008,092,818,711,693,940,737

