Carnegie Mellon University Technical Report CMU-CS-02-114, February 2002 (revised).
Theodore M. Wong, Chenxi Wang*, Jeannette M. Wing
School of Computer Science
*Dept. of Electrical and Computer Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
http://www.pdl.cmu.edu/
We present a new protocol for verifiably redistributing secrets from
an (m,n) threshold sharing scheme to an (m',n') scheme. Our protocol
guards against dynamic adversaries. We wobserve that existing protocols
either cannot be readily extended to allow redistribution between different
threshold schemes, or have vulnerabilities that allow faulty old shareholders
to distribute invalid shares to new shareholders. Our primary
contribution is that in our protocol, new shareholders can verify the
validity of their shares after redistribution between different threshold
schemes.
FULL PAPER: pdf / postscript