
386 Cryptography with Open-Source Software
Local Author ities V
j,k
Q
j,k
C
r
Q
j,k
C
n
Local Auth 1
P
k
v
i,1,k
Q
k
g
v
i,1,k
i
Q
k
g
v
i,1,k
Local Auth 2
P
k
v
i,2,k
Q
k
g
v
i,2,k
i
Q
k
g
v
i,2,k
.
.
.
Local Auth j
P
k
v
i,j,k
Q
k
g
v
i,j,k
i
Q
k
g
v
i,j,k
.
.
.
Local Auth l
P
k
v
i,l,k
Q
k
g
v
i,l,k
i
Q
k
g
v
i,l,k
Sum of A
i
P
j,k
v
i,j,k
Q
j,k
g
v
i,j,k
i
Q
j,k
g
v
i,j,k
⇓ decrypts
P
j,k
v
i,j,k
TABLE 14 .2: The regional Bulletin Board
Regional Authorities V
i,j,k
Q
i,j,k
C
n
Regional Auth 1
P
j,k
v
1,j,k
Q
j,k
g
v
1,j,k
i
Regional Auth 2
P
j,k
v
2,j,k
Q
j,k
g
v
2,j,k
i
.
.
.
Regional Auth i
P
j,k
v
i,j,k
Q
j,k
g
v
i,j,k
i
.
.
.
Regional Auth l
P
j,k
v
l,j,k
Q
j,k
g
v
l,j,k
i
Sum of A
P
i,j,k
v
i,j,k
Q
i,j,k
g
v
i,j,k
i
⇓ decrypts
P
i,j,k
v
i,j,k
TABLE 14.3: The national Bulletin Board