Table 1 Notation summary

N

Number of users

H(·)

Binary entropy function

x _u

Input of user u

F(·)

Output function

k

Number of runs (or rounds)

\({\mathcal {X}}\)

Random input distribution

y _r

Output at run r

U _S

Set of static users

U _D

Set of dynamic users

U _r

Set of users available at run r

T _r

Random subset of U _r

M

Cardinality of T _r

\({\mathcal {A}}\)

The service party

h(·)

Hash function