The anonymity provided by the threshold ring signature scheme proposed by Bres-son et al (Crypto'02) is perfect. However, its complexity is prohibitively large even for relatively small sets of signers. We propose use of threshold schemes based on covering designs that are efficient for large groups of signers. The cost we pay is non-perfect anonymity.
The Office of Graduate Studies has verified and approved the above named committee members. ii To my late father, who considered knowledge and education among the most important and valuable things. Wish you were here. iii ACKNOWLEDGEMENTS I would like to thank my family, for their unconditional support and love. I thank my mother Elica for her belief in… (More)