Crandall was most notable for the development of the irrational base discrete weighted transform, an important method of finding very large primes. He was, at various times, Chief Scientist at NeXT Inc. and Apple's Chief Cryptographer. At the time of his death on December 20, 2012, Crandall was the Vollum Adjunct Professor of Science and director of the Center for Advanced Computation at Reed College. He fronted a band called the Chameleons in 1981. Crandall was also Apple Distinguished Scientist and head of Apple's Advanced Computation Group. His Erdős number is 2.
He was awarded numerous patents for his work in the field of cryptography. Crandall also owned and operated PSI Press, an online publishing company.
Crandall died in Portland, Oregon on the morning of December 20, 2012 after a short bout with acute leukemia. He was 64 years old.