Secret information is shared by a group of members by giving each member a
first share of the information. To reconstruct the secret information, a
subgroup consisting of some or all of the members generate second shares
from their first shares, and distribute the second shares to the other
members of the subgroup. Each member of the subgroup performs an
operation on the second shares it receives and one second share it
generated itself to obtain an intermediate result. The intermediate
results are transmitted to one or more members of the subgroup, or to a
central facility, where the original secret information is obtained from
a further operation performed on the intermediate results. The original
secret information can thereby be obtained without compromising the
secrecy of the first shares, and without forcing the members to reveal
their identities.